NBT

PU8UCATION8 REFERENCE

AlllDb atE73S

NBSIR 75-926

The National Measurement

System for Length and Related

Dimensional Measurements,

Part I

J. W. Lazar

R. L Bach

Institute for Basic Standards

National Bureau of Standards

Washington, D. C. 20234

Final

March 1976

Issued August 1976

/OO

LLSL lONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

NBSIR 75-926

THE NATIONAL MEASUREMENT

SYSTEM FOR LENGTH AND RELATED

DIMENSIONAL MEASUREMENTS,

PART I

J. W. Lazar

R. L Bach

Institute for Basic Standards

National Bureau of Standards

Washington, D. C. 20234

Final

March 1976

Issued August 1 976

U.S. DEPARTMENT OF COMMERCE, Elliot L. Richardson, Secretary

Edward O. Vetter. Under Secretary

Dr. Betsy Ancker-Johnson, Assistant Secretary for Science and Technology

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Acting Director
CONTENTS

Page

EXECUTIVE SUMMARY 2

1. INTRODUCTION 3 1.1 Importance of Dimensional Measurements 3 1.2 Purpose of Study 5 2. STRUCTURE OF THE MEASUREMENT SYSTEM FOR LENGTH 7 2.1 Conceptual System 7 2.2 Basic Technical Infrastructure- 8 2.2.1 Documentary Specification System 8 2.2.1.1 Docummentary Standards - General 8

2.2.1.2 API Standards 9 2.2.2 Instrumentation System 11

2.2.2.1 Measurement Tools and Techniques 12 2.2.2.1.1 Artifact Standards 12 2.2.2.1.2 Dimensional Measurement Instrumentation 17 2.2.2.2 The Instrumentation Industry 20

2.2.3 Reference Data 23

2.2.4 Reference Materials 23

2.2.5 Science and People 23

2.3 Realized Measurement Capabilities 24

2.4 Dissemination and Enforcement Network 31

2.4.1 Central Standards Authorities 31

2.4.2 State and Local Offices of Weights and Measures 31

• 2.4.3 Standards and Testing Laboratories and Services 33

2.4.4 Regulatory Agencies 33

2.5 Direct Measurements Transactions Matrix 33

2.5.1 Analysis of Suppliers and Users 33

2.5.2 Highlights Regarding Major Users 33

2.5.2.1 Air Frames, Engines, Aircraft Equipment 33

2.5.2.2 Ball and Roller Bearings 36

. 2.5.2.3 Gears 37

2.5.2.4 Geodetic Investigations 37

2.5.2.5 Integrated Circuit Industry 39

2.5.2.6 Machine Tool Industry 40

2.5.2.7 Marine Engineering 40

2.5.2.8 Metrology 40

2.5.2.9 Petroleum Industry 41

2.5.2.10 Photogrammetry 42

2.5.2.11 Research and Development 42

2.5.2.12 Screw Thread Industry 43

2.5.2.13 Watch Industry 43

2.5.2.14 General Public 44

2.5.3 Summary Discussion of Major Users of NBS Services 44

3. IMPORT, STATUS, AND TRENDS OF THE MEASUREMENT SYSTEM 45

3.1 Impact of Measurements 45

3.1.1 Functional, Technological, and Scientific Applications 45

3.1.2 Economic Impacts - Costs and Benefits 46

3.1.3 Social, Human, Person-on-the-Street Impacts 46

3.2 Status and Trends of the System 47

4. SURVEY OF NBS SERVICES 49

4.1 The Past 49

4.2 The Present - Scope of NBS Services 49

4.2.1 Description of NBS Services 49

4.2.2 Users of NBS Services 49

4.2.3 Alternate Sources 49

4.2.4 Funding Sources for NBS Services 49

4.2.5 Mechanism for Supplying Services 50 4.3 Impact of NBS Services 50

4.3.1 Economic Impact of Major User Classes 50

4.3.1.1 Gage Block - End Standards 50

i i
Page

4.3.1.2 Tapes - Line Standards 53

4.3.1.3 American Petroleum Institute (API) Gages 55 4.3.1.4 Angular Standards 57

4.3.1.5 Related Dimensional Artifacts 58

4.3.2 Technological Impact of NBS Services 59

4.3.3 Pay-off from Changes in NBS Services 59 4.4 Evaluation of NBS Program 59

4.4.1 Response to Questions in Industry Survey 60

4.4.2 Contacts with Technical and Trade Societies and Journals 62

4.4.3 "Outreach" Program 63

4.4.4 Exhibit in the International Machine Tool Show 1974 65

4.4.5 High Efficiency Methods for Dimensional Calibrations 65

4.4.6 Analysis of Data Base 65

4.5 The Future 66

4.5.1 Current Major Technical Projects 66

4.5.2 Distribution of Effort 67

4.5.3 Time Table for Continuing Analysis and Acquisition of Data 67

5. SUMMARY AND CONCLUSIONS 69

APPENDIX A. METHODOLOGY OF THE STUDY 70

APPENDIX B. SUMMARY OF BACKGROUND DOCUMENTS 74

APPENDIX C. MANUFACTURERS OF DIMENSIONAL ARTIFACTS 75

APPENDIX D. TYPICAL INDUSTRY SPECIFICATIONS FOR RULINGS 77 APPENDIX E. STATE LABORATORIES CAPABILITIES (PHYSICAL DIMENSIONS) 78

APPENDIX F. GOVERNMENT AND INDUSTRIAL LABORATORY CAPABILITIES (PHYSICAL DIMENSIONS). 73

APPENDIX G. NORTH AMERICAN DATUM 80

APPENDIX H. THE ANSI OPTIMUM METRIC FASTENER COMMITTEE IO3

REFERENCES 108

BIBLIOGRAPHY 108

LIST OF FIGURES

Figure 1-1. Regions of distance measurements 3 Figure 1-2. Accelerating rise in precision 4 Figure 2-1. Infrastructure of the National Measurement System for Length and

Related Dimensional Measurements 6 Figure 2-2. Infrastructure example of user - machine tool and gage manufacturer 8 Figure 2-3. Infrastructure of API standards 10 Figure 2-4. Capability of NBS in first transfer to length standards 11 Figure 2-5. Examples of end and line standards 13 Figure 2-6. Optical height gage 14 Figure 2-7. 18-inch step gage (end standard) 14 Figure 2-8. Calibration of a line standard with interferometry 15 Figure 2-9. NPL gage interferometer 18 Figure 2-10. Principles of the linear voltage differential transformer (LVDT) 19

Figure 2-11. Principles of electronic distance measuring device (EDM) 20

Figure 2-12. Best routine accuracy for end standard measurements at NBS 25

Figure 2-13. Linear length measurement capabilities in the aerospace industry 25

Figure 2-14. Linear length measurement capabilities in the ball and roller

bearing industry 25

Figure 2-15. Characteristics of typical ranging devices now available 25

Figure 2-16. Accuracy requirements for integrated circuit camera 25

Figure 2-17. Accuracy requirements of metrology 25

Figure 2-18. Accuracy requirements of photogrammetry 26

Figure 2-19. Results of measuring masters on three different measuring

machines for integrated circuit (I.C.) industry 26

Figure 2-20. Survey by NPL - standard deviation of industrial errors from

NPL measurements 27 Figure 2-21. Recent NCSL survey .02 inch gage block showing measured values

and estimated uncertainty for NBS and ten other participating labs 28

Figure 2-22. Measurements on internal diameter - 2.000 inch ring gage showing

measured values and estimated uncertainties for NBS and other labs 29

Figure 2-23. External diameter measurements - 0.1250 inch steel ball showing measured value and estimated uncertainty for NBS and other labs 29

iii
Page

Figure 2-24. 5 degree angle block showing measured values and estimated uncertainty

for NBS and other labs 30

Figure 2-25. Length bench in states weights and measures lab and associated

standards 32 Figure 2-26. Example of dimensional measurements needed by aerospace industry. 35

Figure 2-27. Step and repeat process in IC industry 39

Figure 2-28. Standard gages developed by the American Petroleum Institute (API) 42

Figure 2-29. Typical drill -stem assembly for oil industry (from API Spec. 7). 42

Figure 2-30. Example of measurements in screw-thread industry 43

Figure 3-1. Impact of length. 45

Figure 4-1. NBS customer profile - gage blocks 74% evaluation - total value of

NBS calibrations for companies 1970-1973 base period. 50

Figure 4-2. NBS customer profile - gage blocks, 74% evaluation - frequency of

listing of SIC codes. 52 Figure 4-3. NBS customer profile - gage blocks, 74% evaluation - frequency of

listing of SIC codes. 52

Figure 4-4. NBS customer profile - gage blocks, 74% evaluation - frequency of

listing of SIC codes. 52 Figure 4-5. NBS customer profile - gage blocks, 74% evaluation - number of

companies versus value of shipments 53 Figure 4-6. NBS customer profile - tapes, 46% evaluation - NBS total calibrations for system for years 70 - 73 54

Figure 4-7. NBS customer profile - tapes, 46% evaluation - frequency of listing

of SIC codes 54

Figure 4-8. NBS customer profile - tapes, 46% evaluation - frequency of listing

of SIC codes 55

Figure 4-9. NBS customer profile - tapes, 46% evaluation - frequency of listing

of SIC codes 55 Figure 4-10. NBS customer profile - tapes, cross section of "medium-size"

companies 55 Figure 4-11. NBS customer profile - tapes, cross section of "large" companies 55 Figure 4-12. NBS customer profile - line standards, 76% evaluation - frequency

of listing of SIC codes. 55

Figure 4-13. NBS customer profile - line standards, 76% evaluation - frequency

of listing of SIC codes 55 Figure 4-14. NBS customer profile- line standards, 76% evaluation - value of

shipments. 56

Figure 4-15. NBS customer profile - API gages, 65% evaluation - frequency of

listing of SIC codes 56

Figure 4-16. NBS customer profile - angle blocks, 93% evaluation 57

Figure 4-17. NBS customer profile - other angular standards, 87% evaluation 57 Figure 4-18. NBS customer profile - optical flats, 64% evaluation 58

Figure 4-19. NBS customer profile - other dimensional standards, 71% evaluation 58

Figure 4-20. Input-output for NBS - length and related dimensional measurements 68

LIST OF TABLES

Table 1-1. Analysis of measurements-intensive factors on economy. 5 Table 2-1. Classes of instrumentation. 17

Table 2-2. Total of coordinate measuring machines per industry. 21 Table 2-3. Industry-product analysis of the machine tool accessories industry

(SIC 3545). 22

Table 2-4. General statistics for the machine tool industry 22

Table 2-5. Value of shipments for SIC 3545. 23

Table 2-6. Shipments of products and services of several industries 24

Table 2-7. Typical NBS working accuracies for angular standards 24

Table 2-8. Results of partially completed audit among industrial/government labs

with computed standard deviation for all results 30

Table 2-9. Direct measurements transactions matrix. 34

Table 2-10. Aerospace: economic trends and projections 36

Table 2-11. Typical measurements with EDM microwave ranging device 38

Table 2-12. Sales of a "typical" machine tool manufacturer 1967-1974 44

Table 4-1. Gage block - NBS customer list - including company name, annual

iv
Page

sales and standard industrial classification (SIC) code number 51 Table 4-2. NBS customer list - tapes. 53

Table 4-3. Users of tapes other than industrial. 54

Table 4-4. Users of tapes other than industrial. 54

Table 4-5. NBS customer list - line standards. 56

Table 4-6. Users of line standards other than tapes. 56

Table 4-7. NBS customer list - API gages. 56

Table 4-8. NBS customer list - angular standards. 58

Table 4-9. NBS customer list - other dimensional standards. 58

V
I
THE NATIONAL MEASUREMENT SYSTEM FOR LENGTH AND RELATED DIMENSIONAL MEASUREMENTS

PART I

J. W. Lazar and R. L. Bach*

Mechanics Division

EXECUTIVE SUMMARY

The determination of length and related

dimensional measurements constitute the

largest group of measurements made in sci- ence, manufacturing, and technology. It has

been estimated that 80% of all measurements

made in industry are of length and displacement. Figures developed from our recent

study of the National Measurement System

shows that an average of $9.4 billion is ex- pended annually by the manufacturing sector

alone to perform dimensional measurements in our economy.

Length and related dimensional measurements have impact upon many areas of the

economy. The largest area is in manufacturing and within manufacturing the firstorder impact areas are air frames and aircraft equipment, ball and roller bearings,

car accessories, domestic appliances, electronic equipment, gears, general engineering,

geodetic investigations, integrated circuit

industry, photogrammetry , research and development, screwthread industry, scientific

instruments, and watches. In many of these

areas dimensional measurements are made to satisfy functionality requirements and little

else. For example, the parts of an automobile engine would not fit properly if they were measured with different micrometers

which were not accurately calibrated.

In the course of our National Measurement

System study in Length and Related Dimensional Measurements, we have established

over one hundred and fifty contacts with

individuals within governmental agencies;

industry; professional societies and organizations; scientific and trade journals; and

universities and colleges around the nation.

Many of these people contacted were sur- prised that we were willing to listen to their problems in dimensional measurements.

In almost all cases, the organizations con- tacted expressed a keen desire to continue

the dialogue established between the Bureau

and their personnel .

* A major portion of the original research

work for this study was performed by a for- mer NBS employee, B. Nelson Norden, now with

Monsanto Chemical Company of Pensacola,

Florida

The primary industrial contact was within

Standard Industrial Classification 3548, Ma- chine Tool Accessories and Measuring Devices.

This industry was expanded into further prouct codes such as 35452, Precision Measuring

Tools; 3545211, Comparators; 354221, Gage

Blocks; etc. In many cases the contacts ex- pressed no pressing need for any greater

accuracy in standards for dimensional mea- surements. For example, the accuracy inherent

in various dimensional artifacts (gage blocks,

etc.) and instrumentation (laser interferometers, etc.) far outpaces the ability of many

to transfer displacements obtained from these

devices to other objects. (This is verified

by viewing the results of some recent surveys

contained in our report illustrating inconsistencies of 0. 00177mm to 0.00254mm-70 to 100 microinches-in the measurement of internal diameters of finely finished ring gages.)

The primary users of the National Bureau of

Standards' most accurate dimensional measurements are the Department of Defense Primary

Standard Laboratories, the various gage and

measurement instrument manufacturers, and the

private standards laboratories including those

who only service the parent organization.

Another major user category of NBS ser- vices is the machine tool industry. In the

recent U.S. Industrial Outlook 1973, the machine tool industry ranked first in percentage

increase in value of shipments from 1972 to 1973 (27 percent increase from $0,825 billion

to $1,050 billion). An increasing percentage

of manufacturing is being done under numerical control (NC). NC machine tool shipments

are growing three times as fast as conventional machines and it is estimated that 15-

20% of U.S. metalworking machine tool shipments are currently NC. There are pressing

needs to develop standards and algorithms to characterize the accuracy of these machines.

The reason for accurate calibration of NC machines is that the accuracy of parts produced is totally dependent on the inherent

positioning accuracy and geometry of the

machine tool .

' The areas of surveying and geodetic investigations are frequent users of NBS calibration facilities (tapes). In recent years

calibrations have been steadily declining and

the 1974 NBS calibrations in this area were

only approximately 20% of the same services

in 1971. We have found that with the recent

1
advent of relatively inexpensive electronic

distance measuring devices, many companies

and individuals are now able to afford these

devices

We had initiated steps to interact with

the machine tool industry to a greater ex- tent even to the point of obtaining complimentary exhibit space in the International

Machine Tool Show (IMTS) in September 1974 in

Chicago. The specific purpose of our exhibit

was to listen to and view first-hand some of

the measurement problems within this important area. Four hundred and sixty-one people

requested 1300 copies of the various dimensional technology and optics and micrometrology reports. The majority of these reports

are the "how we do it" type.

Space has already been reserved for another

NBS exhibit at the next IMTS in September

1976.

One fact has been repeatedly borne out

from all contacts - the need for more awareness of the work being done at NBS and the

need for more publications at multi levels

discussing how to make accurate and precise

measurements

The results of the recent NCSL audit package measurements show the need for dimenional artifacts to verify the accuracy and

precision of industry's gages and measurement system other than the standard set of

gage blocks, angle blocks, plug and ring

gages, spheres, etc. NBS should develop

these standards and make them available to the various laboratories for their use to determine the accuracy and precision of their

measurement system. In addition NBS should

develop, in conjunction with industry, a three dimensional artifact to be used to determine the accuracy of their three dimensional measuring machines as well as their

complex NC machining centers.

2
1. INTRODUCTION

This microstudy has been divided into two parts, static and dynamic linear measurements.

Part I examines all the aspects of linear mea- surements of stationary objects such as gage

blocks, line scales, angle blocks, etc. Part II is concerned with the measurement of

linear motion versus time such as the mea- surement of displacement and amplitude of an object being subjected to a vibration or shock

Quality Control, an elusive concept, usu- ally determines if a product which fulfills

a need returns a profit or a loss to the producing company. It applies to all steps in

the production of an item to the form, shape,

or size of the unique parts that constitute a final product. In other words, does the geometry of the machines that manufacture these

parts (accuracy of lead screws, orthogonality

of spindle and table and flatness of surfaces)

meet the functional requirements? Do the individual parts fabricated on these machines

meet the requirements of the drawings for

these parts as to form, shape, or size so that they will be compatible with other parts

made in other places on other machines? If

the National Measurement System is alive and

working and if all industries truly are part

of it and periodically calibrate their machines and gages to the artifacts at NBS, perhaps three or four places down the calibration chain through commercial standards laboratories, then these parts will fit and

function as specified. It is the function

of the Quality Control or Quality Assurance

Departments of all industry to see that this

does indeed happen.

1.1 Importance of Dimensional Measurements

Phenomenal progress has been achieved during the past decades in areas of product design, manufacturing and quality control. In 1800, a precision of 0.25mm was adequate for

length measurements; in 1900, the need for

0.01mm was felt; in 1950, precision needs were 0.25ijm, and currently some industrial

applications need 12nm. Figure 1-2 illustrates the rapid progression of industry's

demand for precision. We see that whereas

mechanical assembly was formerly accomplished

by individual adjustment of the components,

once mass production became possible, the demand for precision soared.

The need for increased precision resulted

primarily from:

Cl) Component dimensioning closer to the

theoretical size limits to achieve material

and cost savings.

(2) Trends toward miniaturization which have

resulted in reduced tolerances for various

components

(3) Increased life and reliability for products such as gears and bearings which require

tighter tolerances on size and form.

C4) General interchangeabil ity and uniform

accuracy of parts to improve the maintainability of assemblies on a world-wide system.

[5) Automatic assembly, often occurring at

tremendous speed, requires that the various

components must be manufactured and assembled

consistently and must be able to perform within small margins of error. There is no universally accepted classification of the regions comprising the spectrum

of dimensional (length) measurements but for

clarity we have roughly grouped the regions

into five groups as shown in figure 1-1.

[

CELESTIAL

nAVIGATION I

SURVEYING

i manupacturing

|

/micro

/ RANGE _l I I I 1 1 i 1 1 ' 1 '

10"' 10* 10"' 10'' 10"' 10"' 1 lo' lo' lo' lo' lo' lo'

DISPLACEMENT IN METERS

Figure 1-1. Regions of distance measurements.

Since most of the spectrum for dimensional

measurements is covered by the manufacturing

and surveying regions and many of the devices

and methods for measurement spill over to the

other regions, our main area of focus for this

study will concentrate in these two regions.

The determination of lengths constitutes

the largest group of measurements made in science, industry, and technology. It has

been estimated (43rd ANZAAS Congress 1971)

that 80% of all measurements^ made in industry are of displacement [1]. Some reliable

estimates that we have found during our data

acquisition are that investments in mea- suring all facets of length constitute approximately l7o of the annual value of shipments of industry. In the area of con- struction, ratios derived from experience

in land and engineering surveys show that 10%

of new construction requires precise control

and 1% of new construction costs are charged

to survey activity which directly involve

length measurements. Thus, we can develop

Figures in brackets indicate references

listed at the end of this paper.

3
1700 -,

1725

1750

1775

1800

1772 Watt's Dial Indicator

1775 Wilkinson's Boring Mill

1776 Watt's Steam Engine

1793 Whitney's Cotton Gin

1800 Maudslay's Screw Cutting Lathe

1805 Maudslay's 0.001 inch measuring instrument

1807 Fulton's Steamboat

1825 - 1834 Mccormick's

1838 Davenport's

Reaper

Electric Motor

1850 1851 Brown's Vernier Caliper

1856 Bessemer's Steel Furnace

1875 -

1900 -

1925

1950 -

1917 World War I,

1878 Edison's Incandescent Lamp

1885 Daimler's Gasoline Engine

1893 Michel son's Interferometer

1896 Johansson's Gage Blocks

1898 Curie's Radium

1898 Taylor and White's High Speed Steel

1903 Ford's Model T Automobile

1903 Wright's Airplane

1905 Einstein's Relativity

1907 DeForest's Electronic Tube

1911 Sperry's Gyro Compass

1919 Rutherford's Atom-Smashing Theory

1922 Taylor and Young's radar

1941 World War II 1948 Transistor invented

1960

1957 First man-made satellite orbited

1962 "Relay" satellite orbited

1970

Figure 1-2. Accelerating rise in precision.

4
figures (table 1-1) for the measurement intensive nature of manufacturing and construction using Department of Commerce 1973 figures for the values of this area of the economy. In the area of manufacturing we see the

cost of dimensional measurements ranges from

estimates of $3.9 to $13.4 billion, the values of $3.9, $10, and $13.4 billion (avg. of

$9.4 billion) agreeing quite well considering

they were derived from independent sources. The point is dimensional measurements com- prise a substantial part of this nation 's eaonomy

,

The exact numbers are not of critical

importance, but it is important to recognize

that modern production depends on interchangeability and uniformity of parts. The only

way to provide this interchangeabil ity is

through accurate and precise dimensional mea- surements .

1 .2 Purpose of Study

To understand the complexities of technology and the ramifications of NBS work, the

concept of a National Measurement System was proposed. The purpose of the system is to provide a foundation for interchangeabil ity

and decisions which affect commerce, science,

and the economy. An analysis of the National

Measurement System would serve as a focal

point for discussions concerning problems

within the system. This study will identify

and examine the areas of dimensional mea- surement . Our contacts with industry have shown that

there is widespread interest in studies such

as this one and that they should be made

available to the public. This study of the

National Measurement System for Length is organized along the following topics:

Table 1-1. Analysis of dimensional measurement-intensive factors in the economy.

SIC

Code* Description 1973 Value

($ billions)

Cost of

Measurement

($ billions)

Cost of

Dimensional Measurements

($ billions)

20 - 39 Manufacturing 485.03 16.8' 3.97' 10.0 13.4'

15 - 17 Construction 150.0° 1.5'

a - From Department of Commerce 1973 Outlook Appendix A.

b - Percentage based on figures by Shirleigh Silverman, Associate Director, NBS, 1969.

c - From recent industry canvass by author. Percentage is based on companies' investments

in dimensional measurements vs. value of shipments,

d - From recent industry canvass by author. Estimate of all companies' investments in length measurements from respected personal sources,

e - Estimate that 80% of all measurements made in industry are of displacement. 43rd

ANZAAS Congress, 1971.

f - One percent of construction is spent on survey work. NOAA, "The North American Datum,"

October 1973 (see Appendix G). Note: 1973 GNP $1.27 trillion. September 1973 Survey of Current Business, Vol 53. #9.

*Standard Industrial Classification - two digit code.

5
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(1) Defining the assessment task.

(2) Describing the relevant technologies

which support the primary technology.

C3) Developing non-technological factors

which influence the relevant technologies.

(4) Identifying impact areas.

(5) Making preliminary impact analyses.

(6) Identifying possible action options.

(7) Completing the impact analyses.

In applying this methodology we began by

defining the assessment task in terms of the

following questions:

(1) What is the present state of the NBS

measurement capability?

(2) How are the measurement services of NBS

used? By which firms, industries, technologies and agencies? What is the most effective interface with industry, government agencies, state and local authorities, and professional associations?

(3) What are the methods and instruments by

which practical length measurements are made?

What is the transfer chain from NBS to the

final product? What are the most important

present and future deficiencies in the area

of dimensional measurements?

(4) Are there any services in length which

NBS should commence, delete, or improve upon?

2. STRUCTURE OF THE MEASUREMENT SYSTEM

FOR LENGTH

A unit may be defined as the magnitude of

a quantity in terms of which magnitudes of

other quantities of the same kind are ex- pressed, e.g. a millimeter is a unit of length

which is 1/1000 of a meter, a centimeter is a unit of length which is 10 millimeters or 1/100 of a meter, a decimeter is a unit of

length which is 100 millimeters or 10 centimeters or 1/10 of a meter. A standard can

be defined as "something that is set up and

established by authority as a rule for the measure of quantity, weight, extent, value,

or quality". In terms of these definitions,

dimensional measurements are conducted for

the determination of point to point relationships by the assignment of a number of arbitrary units which indicate lengths.

The units of measurement under consideration in this document are related to the

standard of length, the meter. The meter is

defined as 1,650,763.73 vacuum wavelengths of

light resulting from the atomic energy level

transition 2p,„-5dr- of the isotope of krypton (86Kr). 10 5 To facilitate better overall comprehension

of the National Measurement System for length,

we have developed a model of the system. This

model is comprised of the following categories:

(1) Scientific and Technological Base for

Length: This includes the definition of the

unit under consideration and the international

agreement upon which this is based.

(2) "Recognized" advocates of standards:

This category includes the national laboratories and all pertinent writers of standards

and/or specifications.

(3) Documentary Standards: The category of

"paper" standards includes a listing of the

pertinent specifications which are set up for industry with specific emphasis on dimensional measurements.

(4) Artifacts used in Transfer/Control:

This includes "hardware standards" which are

used for either the transfer of the unit of

length or for a controlling process which

involves the unit, except in some electronic

cases, an artifact can be thought of as having

no moving parts, e.g. a gage block.

C5) Instrumentation used in Transfer/Control:

This subgroup contains an analysis of the

instrumentation used within the National

Measurement System for transfer and/or control of the unit of length.

C6) Users of the unit of length: This category is by far the largest and includes industries which need dimensional measurements.

Figure 2-1 depicts the infrastructure of

the National Measurement System for the unit

of length and dimensional measurements.

To illustrate how complex one specific

area of users can become we have depicted a detailed infrastructure of the machine tool

and gage manufacturers (fig. 2-2).

2.1 Conceptual System

In 1875, an international treaty, the

"Treaty of the Meter" was established to set

UP defined standards for length and mass. The General Conference of Weights and Measures, which is the meeting at the diplomatic

and political level of the signatories to the treaity, meets periodically to recommend

improvements to the system of standards.

In 1960, the Eleventh General Conference

on Weights and Measures defined the new

International Standard of Length as 1,650,763.73 vacuum wavelength of light

resulting from the unperturbed atomic energy

level transition Zp-^Q-Exic^ of the krypton isotope having an atomic weight of 86. This

orange-red radiation was chosen over other

wavelengths because its wavelength was the

best defined one known at the time. One

inch is defined as 2.54 centimeters exactly.

One of the most important fundamental con- stants of nature is the speed of electromagnetic radiation, the speed of light (c). It

is used quite extensively in ranging because

very accurate delay times can be measured

and the appropriate conversion from time to distance can be made by using the speed of

7
TREATY OF THE

ELECT, a ION TECHIQUEsI

I

meter|

MEAS. MACH. CHARACTERIZATION

OTHER (API)}i - - NBSB S

[*-

SPECIALIZED STDS

ARTIFACTS DEFINED —1 '

MACHINE TOOL

PRODUCT I

1 USERl USER ^

ISO-IEC- COPANT

AST M Hi

OPTIMUM METRIC THDS.

ANSI

INDUSTRIAL STDS

FED. specs! 000

NATIONAL STDS

ARTIFACTS DEFINED

MIL STDS MIL SPECS

PRIMARY STD LABS

5f

ti .AND GAGE MANUFACTURERS 3—

MEAS. MACH. MANUFACTURERS

I PRODUCT 1

^

USER USER

INFORMATION AND CONSULTATION

CALIBRATION TRACEABLE TO NATIONAL STDS

VOLUNTARY STANDARDS — MEASUREMENT DATA

ISO — INTERNATIONAL ORGANIZATION FOR STANDARDIZATION

IE C — INTE RN ATIONAL E L E C T R OT E C H NIC A L COMMISSION COPA NT - PAN AME RIC AN STANDARDS COMMISSION

API — AMERICAN PETROLEUM INSTITUTE ASTM- AMERICAN SOCIETY FOR TESTING MATERIALS

ANSI -AMERICAN NATIONAL STANDARDS INSTITUTE

MIL - MILITARY DOD -DEPARTMENT OF DEFENSE

Figure 2-2. Infrastructure example of user-machine tool and gage manufacturers.

light.

Since the advent of reproducible and stable

lasers it is now possible to measure optical

lengths more precisely than the definition of

the meter allows. The methane-stabilized

He-Ne laser frequency is reproducible to 3 parts in 10^2 a^id further work is likely to improve upon this. The definable usefulness

of the current krypton 86 length standard is

approximately 3 to 5 parts in 109.

2.2 Basic Technical Infrastructure

2.2.1 Documentary Specification System

2.2.1.1 Documentary Standards - General

Organizations concerned with industrial

and commercial standards are found at the

international, national, and even lower levels

such as states, counties, municipalities and

throughout industry. With few exceptions

these organizations in the U.S. are non- governmental and the standards published are

used voluntarily by industry and government.

The main international body in the area of

industrial and commercial standards is the

International Organization for Standardization (ISO) whose main function is to develop

international cooperation in standardization

activities. ISO is comprised of national

standard bodies from 69 countries. Its prime

objective is to promote the development of

world-wide standards with a view of facilitating international exchange of goods and

services. From the work of thousands of

technical experts around the world emerge the

ISO Recommendations, which serve to promote

freer international trade by helping to reduce

the differences between various national

standards

.

At the national level, the United States

has a single standards organization that co- ordinates the development and publication of

8
industrial and commercial standards adopted

by industrial associations. This organization is known as the American National Standards Institute (ANSI). Its principal function is to act as a clearinghouse to coordinate the work of standards development in the

private sector, which is currently being

carried on by four hundred different organizations. Through its procedures, timely

development of standards is made possible,

duplication and overlap are minimized and a neutral forum is provided to consider and

identify the need for standards. Through its

recognition by international non-treaty standardization bodies as the National Standards

body of the USA, ANSI serves as the focal

point for organizing USA participation in international standardization. Every industry is affected by and benefits from ANSI

since they rely on many of the 4000 American

National Standards in the course of operation.

The use of American National Standards re- duces the time soent by engineers in designing; improves the deoendabil ity of parts used

in production; reduces the amount of inspection and quality control needed; reduces

inventory costs as a result of being able to operate with a smaller inventory, because of

the ease and speed with which standardized

parts can be obtained.

Listed below are a few of the American

National Standards that are applicable to the

machine tool and gage industry.

(1) Bl.l Unified Screw Threads

(2) B1.2 Gages and Gaging for Unified Screw

Threads

(3) B3.4 Gaging Practices for Ball and Roller Bearing

(4) B3.10 Instrument Precision Ball Bearings

(5) B5.16 Accuracy of Engine and Toolroom

Lathes

(6) B6.1 Tooth Proportions for Coarse-Pitch

Involute Spur Gears.

In addition to these, there are several

hundred other standards that are directly

applicable to the materials used in the con- struction of machine tools and gages such as G25.4 - Gray Iron Castings and H9.20 - Specification for Steel Backed Metal Powder Bearings and Bushing Alloys.

A comprehensive set of standards on dimensional measurements is being developed by a Sectional Committee of the ANSI. Committee

B89 is concerned with dimensional metrology

and currently has reoresentati ves from thirteen technical societies and organizations,

including NBS, and representatives from more

than thirty-six independent compaines.

The Federal Government is also a major

contributor of standards and specifications.

These specifications for purchasing are only

mandatory for the government, but many, such

as military specs, are adapted for non military use. The Department of Defense's (DoD)

"Defense Standardization Program" provides

uniform definitions of the technical requirements for parts, equipment and systems in which the various elements of the DoD have a common interest. Standardization has long

been an important element of military logistics and design, research, and engineering.

Although military specifications and standards

are considered voluntary standards in the

civilian sector, the machine tool and gage

manufacturer must comply with them if any of

his products are to be sold to DoD or be used

by a DoD contractor.

Another branch of the Federal Government

which issues Federal Specifications and Standards is the General Services Administration.

These Federal Specs fill a need for a statement of policy for the development and use of

items in common use in the Federal Government.

The most widely distributed document for precise control of measurements which are dependent UDon gage blocks is specification GGG-G-15a

on gage blocks and accessories. A summary of

this specification is included in Appendix B. Standards for materials, which are the province of American Society of Testing and Ma- terials (ASTM), are the language for the dialogue between buyer and seller. Nearly every

ASTM standard is either a specification or

a test method. Many of the standards are directly applicable to the manufacture of

machine tools and gages since they specify

the exact composition of the iron and steel

used in the tool and gage as well as the test

methods to determine if they meet all the re- quirements of the specification. A few of

such standards are listed below.

(1) ASTM A295 - Carbon-Chromium Ball and

Roller Bearing Steel

(2) ASTM A436 - Austenitic Ductile Iron Castings

(3) ASTM A600 - High Speed Tool Steel

(4) ASTM A307 - Carbon Steel Externally and

Internally Threaded Standard Fasteners.

In addition to the ASTM voluntary standards,

the majority of all machine tool and gage

manufacturers have proprietary standards that

they have developed through years of experience. Most of these are closely guarded

industrial secrets regarding the heat treatment and methods of finishing various steel

and iron alloys that are used in their tools

and gages.

2.2.1.2 API Standards

The foremost example of American industry

standards becoming international standards

are those of the American Petroleum Institute

(API). The principal activities of this In- stitute are simplification, standardization

and imorovement of equipment and methods used

9
API

OTHER ANSI ASTM

2

SPECIFICATIONS AND

STANDARDS

2

ARTIFACTS DEFINED

GAGE MANUFACTURER

PRODUCT MANUFACTURER

USER USER

INFORMATION AND CONSULTATION

CALIBRATION TRACEABLE TO NATIONAL STANDARDS

1^ VOLUNTARY STANDARDS

MEASUREMENT DATA

NBS

OTHER

NAT'L LABS

*ANSI - American National Standards Institute

*ASTM - American Society for Testing and Materials

Fiaure 2-3. Infrastructure of API standards,

10
by the petroleum industry. The fundamental

purpose of this activity is to prepare and

maintain standards and methods acceptable to the industry and the manufacturers of the

equipment. This ouroose is accomplished

through participation and cooperation of

users and manufacturers in the development

and keeping up to date of such standards

and methods.

The standardization committees of the In- stitute have formal representation or informal liaison with numerous societies and asso- ciations including ANSI, ASTM and NBS. The

Institute grants to manufacturers, upon application and submission of a statement of qualifications, the right to affix its official

monogram on material made in accordance with

API standards. Application of the monogram

constitutes a warranty by the manufacturer

that he has comolied with all of the conditions and specifications set forth in the

publication covering material so marked.

Prior to development of these standards,

all items of oil equipment for drilling,

pumping, and oiping were unique for each

manufacturer and could not be interchanged.

With the acceptance of API standards, re- placement parts produced by many different

foreign manufacturers could be purchased in

all oil producing countries with no worry

about interchangeabil ity.

Figure 2-3 shows the API Standards Infrastructure. With the assistance of such other

standards associations within the U.S. as ANSI, ASTM, American Association of Oil Well

Drilling Contractors, American Gas Association and many others, the standardization

committees of the API Division of Production

issue and keep up to date specifications and

standards for all production comoonents used

in the oil industry. NBS is concerned with

only the screw threads of such components as are used in drilling and piping, and through

its membership on the API Gaging Committee

informally oarticipates in any additions,

deletions or corrections in screw threads

for drill stem and pioe. As shown, API issues voluntary standards

which completely define the component or artifact. The prototype is fabricated and

is used as the Grand Master Gage. The set of API Grand Master Gages is maintained at

NBS and to them all other gages in the v/orld are certified. The gage manufacturer, if he

desires to use the API monogram, must fabricate his gages to the requirement of the

standard. In addition, the gage must be

calibrated and certified by NBS or one of

the other National Standard Laboratories

before the monogram can be applied. The

gage is then sold to a manufacturer of oipe,

couplings, valves, etc., who uses this gage,

called a Reference Master Gage, to check his

working gages. Working gages are used to check the production items.

Since these working gages are used very

frequently, they are checked against the producer's Reference Master Gage as soon as they

show signs of wear. If they are found outof-tol erance, they are returned to the gage

manufacturer to be reworked. If they cannot

be reworked to be within the tolerances specified by the API ndard, they are discarded.

Periodically, .e product manufacturer's

Reference Master Gages are returned to NBS

to be calibrated against the Grand Master

Gages. Foreign product manufacturers usually

return their gages to the nearest National

Standards Laboratory for recertification

against the Regional Master Gages. The

National Standards Laboratories do not have

a comolete set of master gages for all sizes

so it is not uncormion for a gage to be shipped halfway around the world to be recertified at NBS. The user of these products also has a set of gages which is used in the field to determine if the screw threads of the pipes, valves, etc. have been damaged during shipment

or handling. These gages are periodically

returned to the gage manufacturers for re- checking and rev/orking if it is found necessary.

2.2.2 Instrumentation System

It has been pointed out that the current

standard of length, the °°Kr lamp, has a useful accuracy of approximately 5 parts in 10^.

But experience demonstrates our inability to transfer the wavelength standard to a material artifact to better than 8 parts in Figure 2-4 shows the approximate state-ofthe-art for the transfer process now at NBS.

10 -

lO"^ 10"* lO ^ 10"^ 10'' I 10 10^ 10^ 10* RANGE (inches)

Figure 2-4. Capability of NBS in first transfer to length standards.

11
The reasons for this lie in the uncertainty

in the correction for the refractive index

of air (or if vacuum is used, imperfect

knowledge of the compression of the artifact as it is returned to atmospheric con- ditions), phase shifts, "wringing" films, etc. The total measurement process can be

thought of as a system consisting of the

operator, environment, measuring algorithm,

and the measuring instrument which comprise

this process. It is a mistaken impression

held by many that the instrument alone determines the final accuracy and precision which

flows from a measurement. In many cases this

is not true. However, before we can talk about

this aspect of the National Measurement System, we must have a feel for the instrumentation

currently on the market.

It is helpful to look at the manufacturers

of various artifacts used in transfer and/or

control of dimensional measurements. Appendix C lists some of the manufacturers of

optical flats, gage balls, gage blocks, optical polygons, measuring tapes and rules,

squares, and screw thread measuring wires [2].

2.2.2.1 Measurement Tools and Techniques

2.2.2.1.1 Artifact Standards

Material artifacts which are used as standards in the transfer and/or control of dimensional measurements can be roughly classified

into five major groups:

(1) End standards - Examoles are gage blocks

which more than any other device form the

basis of interchangeabil ity in this country.

(2) Line standards - Examples are linear

scales for master length reference, linear

scales for feedback control systems, master

tapes used by many industries (see fig. 2.5).

(3) API Gages (American Petroleum Institute)-

These Grand Master Gages can be considered

international artifact standards since all

Master API Gages throughout the world are referenced to them.

(4) Angle standards - Examples are angle

blocks, polygons, and indexing tables used

by various organizations for angular measurements . (5) Related dimensional standards - This

group includes artifacts such as thread measuring wires, master balls, optical flats, etc.

End Standards : As mentioned previously, it

might be theoretically conceivable that all

gages used in manufacturing and quality control should be checked against basic standards,

but in practice it would not be practical or even desirable. The obvious solution is to use primary standards to calibrate secondary

standards and to disseminate the latter throughout the system.

In the late 1800's Carl Johansson of Sweden

was concerned with the idea of developing a small set of gages which could be used in various combinations to eliminate the need

for thousands of fixed gages. He conceived

the idea of gage blocks - blocks of durable

material (steel) with one pair of plane, parallel measuring surfaces. These gage blocks

are one means by which the standard of length

is given physical form and made available for

practical measurement use. Use of gage blocks by industry is not universal because many industries such as foundry work, blacksmithing, carpentry, etc., do

not require the degree of accuracy that gage

blocks can supply. But the production of

firearms, automotive parts, typewriters,

computers, and mechanical and electrical

instruments requires close tolerances so the

gage block has an extremely important role

in such instances.

The essential function of gage blocks is to make available end standards of specific

lengths by temporarily combining several

blocks into a single gaging bar. This com- bination of blocks results in a bar of rea- sonable cohesion whose actual dimension truly

represents the nominal dimension sought.

To accomplish this result we must establish certain specifications:

(1) The individual elements must be available in dimensions to achieve all combinations of sizes within a desired range;

(2) the accuracy of the individual blocks

must be within accepted tolerance requirements ; (3) the individual blocks must be attached

so closely to each other in the built-up con- figuration that the resulting bar will be

equal to the added sizes of the individual

blocks; and

(4) the attachment of the individual blocks

to each other must be firm enough for handling but when "decoupled" the blocks should

be reusable with very little change in their

original size.

Gage blocks are calibrated at NBS for the

manufacturers of gage blocks who then use these "master" calibrated blocks to calibrate

working blocks which are in turn used to calibrate production blocks. Other customers of

NBS gage block calibration services are the

high technology industries.

Application of Gage Blocks : Applications

of gage blocks are so numerous that only a representative sampling can be discussed.

Some of the principal uses are:

(1) Calibration of other gage blocks and

the calibration of sensitive measuring instruments. If one set of blocks has been

measured then it is a simple matter to calibrate another set from the previous set of

12
/

GAGE BLOCKS

\#^STEP GAGE

MAIN SCALE

LINE GRADUATED BAR STANDARDS

DIRECT LENGTH COMPARISON

WITH AUXILIARY ALIGNMENT

DEVICES

684 LINE GRADUATED MASTER SCALES

AUXILIARY SCALE

\

86H

84-

EXTRA FINE GRADUATION LINES OPTICALLY MAGNIFIED FOR OBSERVATION AND ALIGNMENT

GRADUATION LINES OF KNOWN SPACING BUT WITHOUT ASSIGNED

NUMERICAL VALUES

LINE GRADUATED

RULES AND TAPES

Figure 2-5. Examples of end and line standards.

blocks. The accuracy and linearity of measuring may be checked by reference gage blocks.

(2) Setting of comparators and indicator instruments. The average gage of this type measures the variation from the master in one or more dimensions and is easier to use

than gage blocks. Micrometers can be checked

for linearity by gage blocks.

(3) Direct measurement of distances between

surfaces

(4) Checking accuracy of tools and fixtures.

It is very important that tools used in the

manufacture of parts be checked carefully, so the checking of dies, jigs, and fixtures is one of the basic applications of gage blocks.

(5) Checking parts in process of manufacturing. Gage blocks are frequently used in pro- cess inspection because their accuracy enables

the inspector to follow the size of the part

as it approaches the limits of the tolerance.

Other End Standards : The function of an end standard whose gaging surfaces represent

the ends of a specific distance is not limited to gage blocks. Although gage blocks are

the most versatile, there are instances where

other artifact forms are better suited for a particular purpose.

The "measuring rod" is useful when datum

planes have to be transferred beyond the meas

uring range of micrometer screws. An example

is the case of measuring tables of optical in struments whose micrometer screws cover a mea suring range of one inch only, while the useful table movement is larger than this dimension.

The "steo block" or "step gage" consists

of either a series of gage blocks arranged in

a staggered manner to provide steps at various intervals, or is made of a single bar of

steel. One example of the step block is in

surface plate work where the desired height

levels for dimension transfer can quickly and

precisely be established with instruments hav

ing a stepped bar for a master (fig. 2-6).

The step gage is used in certain types of cir

13
Figure 2-6. Optical height gage.

cumstances to check the lead screw accuracy

of measuring machines. Figure 2-7 shows that

the step gage enables one-inch steps to be

contained in a single bar and because it is an end standard great precision can be

achieved with its usage.

Other end standards such as step bars and

gages are calibrated by NBS for industries who

use them to check their manufacturing and/or

measuring machines.

Line Standards : The line standard is one whose length is defined by the separation of

lines engraved on a piece of stable material.

These standards continue to be of great importance in spite of the general availability

of the wavelength standard for length. An important purpose which reference line standards

are intended to serve is the calibration of

line graduated inspection tools and of line

graduated master scales of measuring instruments.

Line Graduated Reference Bars : One form

of line standard is the International Meter

Bar which for many years served as the basis

for precise length measurements. This is a platinum-iridium bar with a Tresca cross- section with fine lines engraved normal to

Figure 2-7. 18-Inch gage (end standard).

the longitudinal axis of the bar on the plane

of the neutral axis. See figure 2-5 for a view of a reference standard bar. Metrology

laboratories serving scientific and industrial institutions have applications for refer- ence bars.

A highly specialized ruling engine is used

for engraving the lines on the bar. Graduations are engraved with a sharp cutting tool

with the view of making these lines as fine

as possible to facilitate using high magnification for readout, to achieve the maximum

accuracy possible from the standard.

NBS has facilities for the calibration of

line standards. This facility is also suitable for the calibrations of subintervals on these bars. The instrument is shown in fig- ure 2-8. In a comparison of 1-meter bars

the error analysis yielded an uncertainty in

the reported values of 0.2 micrometer.

Line Graduated Inspection Bar : The major

function of an inspection bar is to check

the accuracy of common line graduated measuring rules, such as used by toolmakers and

mechanics. During the measurement process,

the inspection bar and the rule to be calibrated must rest on a smooth surface to avoid

major deflections which will cause error.

14
Optical or photoelectric microscope

Line standard

Movable carnage

J—] {1st position)

^Reflecting mirror

Reflecting mirror

Telescope

Beamsplitter

Iodine stabilized laser

I Photo

iDetector

I '

1

' I ' I 2X

Movable carriage (2nd position)

Photo

Detector

Figure 2-8. Calibration of a line standard vn'th interferometry

,

Working Rules : These rules serve as ref- erences when transferring length dimensions

or for direct measurements in which the edge

of the rule is in contact with the object

being measured. Most models of the industrial tyoe graduated rules have more than a single graduation with the most frequently

used graduations in 32nds and 64ths of an inch.

Classes of Line Standards : (1) Reference - suitable as reference standards for makers of precision apparatus and

for use in the most exact scientific work.

(2) Working - suitable for all ordinary precision work and for the needs of college labs,

manufacturers of better grades of scientific

equipment, state weight and measures superintendents . (3) Commercial - suitable for drafting, machine work, etc.

Line Scales : Another form of line standard commonly in use is the line scale.

This can be in the form of ruled scale,

Ronchi ruling, or grid ruling. Line scale

applications include master length reference,

feedback control systems, and master grids

for electronic micro circuits. The operation of some optical instruments for absolute length measurements is based on precise line graduated master scales.

Many master line scales are now manufactured on numerically controlled ruling engines.

The movements are controlled by a feedback

system whose sensors are two Michel son interferometers. The entire system is housed in a cell whose average air temoerature does not

fluctuate more than 0.01°C. Some typical

scale ruling capabilities for linear scales

are:

(1) Maximum line frequency: 2500/inch(200/mm)

(2) Line widths: .0001 to .05 inch (2.5um to 1mm)

_g

(3) Accuracies: Reference scales (4+L)xlO

inches. Inspection scales ( .0001+.000005L)

inches, Commercial scales ( .0005+.0002L)inches

where the formulae apply from any line to any

other line on the scale L inches away.

Master grids can be ruled from 0.0016 , square inches C.Olmm^) to 24 square inches

(155cm2) with line widths ranging from

.0001 inches (.0025mm) to .05 inches (1.27mm).

Precision grids are useful in completely defining accuracy simultaneously in two co- ordinates. Typical capabilities now are:

(1) Line straightness: <+.003 inches (0.075mm) over any ten-inch section

(2) Line parallelism: <0.05 seconds

(3) Line spacing: Maximum error in spacing

15
between one line and a second line at distance L from the first line

(10+1. 5L) X lO'^inches

(250+1. 5L) X lO'^imi.

Ronchi rulings are multiple line rulings

having parallel lines, equally spaced with

the width of the line equal to the width of

the space between the lines. Ronchi rulings

are used in readout and feedback control sys- tems. One of the current specifications on rulings available from industry is shown in Appendix D. Two suoerimposed rulings with

slightly inclined lines will produce interference fringes, with the location dependent

on the relative position of the two. The

operation of certain length measuring machines

is based on the optical observation of the

fringe variations.

Steel Tapes : Until recently, the most

widely used artifacts for measuring lengths

extending over several meters were measuring

tapes. With the advent of electronic distance

measuring devices (EDM's) steel tapes have

been losing oopularity but since they are used

to check reference baselines which are in turn

used to check EDM's, a discussion of tapes is in order.

The industrial steel tape is made from

special tape strips in which the steel has

been heat-treated and tempered to insure the same dimensional stability as is required

of other measuring tools. Industrial measuring tapes are currently made in 25, 50, 75,

and 100-foot lengths and pocket tapes are usually 6 to 8 feet long. The graduations

are made every 1/8 inch on most industrial

tapes and every 1/16 inch on pocket tapes.

There are many types of measuring tapes be- cause there are many users and each profession has devised a "tape with a specific application and accuracy in mind. The users of

tapes will be discussed in detail in sec- tion 2.2.

The National Bureau of Standards has a temperature controlled laboratory with a 200-

foot steel bench that is used for calibrating

tapes. These calibrated tapes can then be

used in general surveying and engineering or

as bench standards by the manufacturers of

measuring tapes. There is also a special

bench for the calibration of the 50-meter

invar base-line tapes used by t :e U.S. Coast

and Geodetic Survey.

API Gages : NBS is the custodian of the

grand master thread gages of the American

Petroleum Institute (API) to which regional

master gages and reference master gages must

be periodically calibrated. The majority of

the reference master gages are measured by

NBS before acceptance by users throughout the

world. Several national standards laboratories who maintain regional master gages participate in the program. The American Petroleum Institute requirement that all master

thread gages carrying their monogram be calibrated to the set of grand master gages at

NBS can be considered mandatory on the gage

manufacturer since a pipe manufacturer would

not buy a master gage if it did not carry the

API monogram. All master API gages throughout the world are referenced to these grand

master gages and through them to the U.S. Na- tional Measurement System. The gages measured at NBS are sold to a manufacturer of

pipe, couplings, etc., who uses these gages

to check his working gages which in turn

are used to check production items.

Angle Standards : Angular standards are normally referred back to the 360° circle.

Angular standards include angle blocks, polygons, indexing tables, rotary tables, angle

generators, optical wedges, and pentaprisms.

NBS calibrates master angle block sets for

industry and also the working sets sent in by

high technology industries. The "typical NBS

working accuracies" for these various artifacts are listed in table 2-7, section 2.3,

and they are more than sufficient for all

known requirements.

Related Dimensional Standards : There are many other artifacts used throughout industry

and by governmental agencies in the meas- urement or control of various dimensions.

These include screw thread wires, steel balls,

plain plug and ring gages, surface plates,

optical flats, roundness standards, gear master profiles, ball plates, grid plates, penetration needles, polariscooe tubes, gill net gages, etc. NBS maintains various of the above that are periodically used in the measurement of

industrial artifacts. The chain from the

meter to all tyoes of these related dimensional standards (except optical flats) is krypton < NBS master gage blocks < measuring

instrument

.

Screw Thread and Gear Wires : Two sets of

wires (hardened steel cylinders of various

diameters, approximately .1 to 25.4 mm (.004

to 1.000 inches)) are normally used in industry, thread measuring wires and gear measuring

wires. These are used for tests in the production, testing and buying of bolts, screws,

pipes, and connectors, gears, etc. NBS calibrates master wires sent by manufacturers and

other industries. Typical measurement uncer- tainty at NBS is 0.12 ym (5 microinches)

.

Steel Balls: Master Ball sets are used by

16
the ball bearing industry and by other high

technology industries such as makers of gyro

comoonents to size production parts. NBS

calibrates such master ball sets and reports

a diameter with a measurement uncertainty of

0.1 micrometer (4.0 microinches)

Plug and Ring Gages : A plug gage is a cylindrical standard and a ring gage is a "hole" standard. These are used throughout industry to check types of gaging systems which in turn are used to perform

quality control on production items. NBS

normally measures the diameter of these items

with a measurement uncertainty of 0.1 micrometer (4.0 microinches).

Optical Flats : An optical flat is used to check on the flatness of components through

optical interference phenomena. They are also

used for the control of other products such

as lenses and other optical elements. At present NBS calibration of optical flats involves

interf erometric measurement with a light source

whose wavelength is compared to the krypton

lamp. The uncertainty reoorted on NBS measured flats is 0.008 micrometer (0.3 microinches) .

Mi seel laneous : Still other dimensional

artifacts exist and NBS is involved in the

measurement of many of these. Typical uses

and working uncertainties for these measurements at NBS are:

(1) Ball Plates - used in calibration of

measuring machines. NBS measurement uncertainty is 0.6 micrometer (25 microinches) depending upon the quality of the balls (roundness and surface finish).

(2) Grid Plates - used by the photogrammetry

field and the microcircuit industry. NBS

measurement uncertainty is less than 0.6 micrometer (25 microinches) for plates with fine

lines (.0015 inch maximum width).

(3) Lead Screws - for precise translation.

NBS uncertainty is 0.5 micrometer (20 microinches) . (4) Screw Threads - for control of production threads. NBS measurement uncertainty

is 2.5 micrometer (100 microinches).

2.2.2.1.2 Dimensional Measurement Instrumentation

Recalling figure 1-1 we see that the

largest number of dimensional measurements

are made in the microdisplacement, industrial,

and surveying ranges. For this reason we

will consider the types of instrumentation

used in these ranges and then we shall take

an in-depth look, by way of the Standard In- dustrial Classification (SIC) codes, of how

widespread the use of some of these instruments are. Since no clear-cut classification of instrumentation exists in the dimensional mea- suring realm, we have developed a system for

the description of the different classes of

instrumentation (table 2-1). The five major

classes are (1) mechanical (2) optical

(3) pneumatic (4) electronic (5) measuring machines.

(1) Mechanical : Mechanical instrumentation

for length measurement is comprised of items

such as mechanical indicators; dial indicators; high sensitivity mechanical indicators;

mechanical comparators; fixed size limit

gages; micrometers, calipers and dividers;

other gages; and rules and taoes. (These

instruments are displacement sensing, amplifying and indicating instruments. Their purpose is to detect variations in a specific

displacement and to display on a dial or scale the amplified version of that sensed

displacement.

)

(2) Optical : Optical instruments used in

length measurement can be subdivided into

four classes - (a) engineering microscopes

(b) projectors (c) interferometers, and

Table 2-1. Classes of instrumentation.

MECHANICAL

Dial Indicators

Micrometers

Calioers, Dividers

Gages

Rules, Taoes

Fabric-measuring

devices

LENGTH & RELATED DIMENSIONAL MEASUREMENTS

OPTICAL

Interferometers

Microscopes

Projectors

Optical Gaging

MEASURING MACHINES

ELECTRONIC

Linear

Mul ti -axi s

Gages (LVDT, capacitance, ultrasonic)

Laser interferometers

Electronic Distance Measuring Devices

(infrared & microwave)

Other methods

PNEUMATIC

Comparators

17
(d) non-contacting gaging systems.

Since the use and application of microscopes and projectors is widespread, they

will not be discussed here.

Interferometry : Light waves are extremely

useful in length measurement because they are

the closest link in the chain to the definition of the meter. The wave nature of light

and the phenomenon of interfering light waves

are the bases of measuring devices based

on interferometry.

Almost all gage block interferometers are variations of Fizeau or Twyman-Green interferometers. An example of one such interferometer is shown in figure 2-9. The light source can be mercury 198, cadmium, krypton86,

or a gas laser. Basically these interferometers measure the length of a gage block

with respect to a base plate to which the

block is "wrung". By determining the number

of fringes between the base plate and the

surface of the block and a known standard

and multiplying this number by half the wavelength of the light used, one is able to determine what constitutes a length of the

gage block.

0 J B

Figure 2-9. N.P.L. gage interferometer.

Light from cadmium lamp (A), or Mercury 198

isotope lamp ^2 "is collected by lens (B) and

focused on entrance slit (C). Light from (C)

is collimated by lens (D) from where it goes

through constant deviation prism (E), whose

rotation determines wavelength passed, through

reference flat (F) to upper surface of gage

block [G) and base plate (H) to which it is

wrung. Light retraces nearly same path to mirror (J) whose fringe patterns are observed

through a telescope not shown. Field of view

is shown below.

Non-Contacting Gaging Systems : A relatively

new product is the non-contacting optical

gage used in inspection and control departments of industry. These units sight on odposite edges of the object being gaged and

determine the deviation of the width or

length measurement from a reference value.

Resolutions as fine as 50 micorinches are claimed. Gaging time is from 2 to 40 milliseconds . Another device utilizes a scanning laser

beam and aoprooriate sensing operations. Resolutions of 0.0005 inch are claimed with ac- curacy figures of 0.0005 inches over a range of

0.0150 to 1.7500 inches. Another interesting

device is a distance indicating optical probe

for noncontact monitoring of thickness, diameter,

roundness, contour', and surface quality of

manufactured production parts. The device,

so says the manufacturer, can gage parts to "10 microinch resolution while standing off

at a distance of 1/8 to 1/2 inch". Speed of

response is approximately 40 microseconds.

The most obvious application is in automatic

inspection where high-speed, precision, non- contacting measurements are basic requirements .

(3) Pneumatic : The operation of pneumatic

gaging is based on phenomena which occur when

pressurized air is impeded in its free flow

through an orifice by impinging against a solid surface. The distance of that solid

surface from the orifice will affect the air

velocity and create a back pressure. If the

induced pressure and volume of air is maintained constant, the variations in the upstream pressure will be a function of the

distance of the obstruction from the orifice.

(4) Electronic Instrumentation : The class

of electronic instrumentation in use to measure dimensions is quite large indeed. We have broken this class of instruments into

the following: (a) Electronic Gages (LVDT

principle) (b) Laser Interferometers

(c) Electronic Distance Measuring Devices

(EDM's) - (infrared, microwave, etc.)

(d) Other Tranducers (capacitance, inductive,

eddy-current , etc . )

.

Electronic gages : Electronic gaging systems

are in widespread use in dimensional measurement because their response time is extremely

short and their output can be used to perform

control functions. Most electronic systems

make use of linear variable differential

transformers (LVDT) which produce an output

which is proportional to the displacement of

a movable core within a field of several

coils (fig. 2-10).

Gage blocks which are used in inspection,

in the toolroom or on the production floor

must be verified in a periodic manner. The

most widely used method consists of comparing

the actual size of the block being inspected

to a master gage block of identical nominal

size. Comparator gages based upon electronically amplified displacement signals are

the basic instruments for length comparison.

18
TENSION ADJUSTING COLLAR

SPWOLE UPPER BUSHING

VOLTAGE OUT

A

1 ^^-^ 1

1

1

t

1 ^' 0 a

1 CORE POSITION

VOLTAGE OUT I OPPOSITE PHfc^lE \ CORE DISPLACEMENT

CC~£. AT A COR£ AT O

(null position)

Figure 2-10. Principles of the Linear

Voltage Differential Transformer (LVDT).

Electronic gages are also used in other applications such as gaging height, measuring

internal diameters, checking roundness, etc. Fringe Counting Laser Interferometers : Since

the advent of the laser (early 1960) it could

be prophesied that it was only a matter of

time before someone develooed a reliable laser

instrument for measuring distances. With its

high degree of coherence, a laser device is

usable over hundreds of meters and its wavelength can be stabilized and determined to a high degree of accuracy. One of these models

has a range of 60 meters with .025 micrometer

resolution and an accuracy better than five

parts in 10^.

The laser interferometers are based on the

Michel son interferometer developed in the

late 1800's. If one of the two mirrors in

this interferometer moves, then alternately

light and dark fringes pass by the observer

and their number is indicative of how far

the mirror has traveled. If the wavelength

of the light is known then it is a simple

matter to convert the fringe count to distance. Current designs on the market are more elaborate than this in that some use

two frequencies and other variations. The

laser interferometer has revolutionized the

machine tool industry and will be discussed

in greater detail in the users' section of

this report.

Electronic Distance Measuring Devices : Some

of the more interesting devices used to measure long distances are devices called electronic distance-measuring devices (EDM) based

on laser, microwave, and infrared wavelengths.

With any type of EDM c-qjip.~.ijr,t, niodulaced waves are transmitted to a target point and

returned (fig. 2-11). The modulation of the

carrier wave is maintained by frequencystabilized devices and the phase relationship between the transmitted and returned

beams of radiation is determined and con- verted to a direct readout of distance.

EDM systems can be found in fields of sur- veying, urban development, construction, mining, agriculture/forestry, and hydrography.

A recent dramatic example of laser ranging

was the mapping of the Grand Canyon to obtain

accurate profiles for a 310-square mile area

of the national park. To establish a reference, four parallel lines of points were es- tablished along the canyon rims and then

cross-referenced with one another with laser

ranging in terms of distance and angle. The

total survey was made in three days with two men, whereas traditional taping measurements

would have taken one year and aoproximately

100 men.

(5) Measuring Machines : The configuration

and size of mechanical parts are determined

by more than a single measurement. Many of

the dimensions are interdependent with re- gard to Dosition and geometry. Characteristics such as built-in accuracy, adaptability,

and versatility for measuring many configurations have resulted in diverse applications

for "measuring machines" in many phases of

industrial production.

19
ELECTRO-OPTICAL DISTANCE MEASURING

EQUIPMENT

TRANSMITTER

MODULATED LIGHT BEAM , RETRO-REFLECTOR

REFLECTED LIGHT BEAM

Figure 2-11. Principles of electronic distance measuring device (EDM)

Measuring machines are stationary machines

(with some moving parts, such as probes) in

which their own "internal standards" are used

to obtain dimensional measurements. Machines

for measurement along one axis only are single-axis machines while multi-axis machines are commonly referred to as coordinate

measuring machines.

Single-Axis Measuring Machines : The most

frequent measurement is usually a linear

distance. The basic types of single-axis

machines are:

(1) Instruments which utilize a master scale

attached to the movable measuring spindle,

(2) Instruments having a horizontal threaded

measuring spindle for the master element, and

(3) Instruments which use optical distance

measuring systems incoroorated in a horizontal carriage.

Coordinate Measuring Machines : In recent

years a new breed of measuring machines has

been developed. In these devices, the traveling member is guided along two straight

linr^ paths representing the X and Y axes of

a rectangular coordinate system with mutually

perpendicular axes. A third axis (Z) is avail

able on some models.

"The Tenth American Machinist Inventory of

Metal Working Equipment'.' published in 1968,

lists the number of coordinate and contour

measuring machines and gear checking machines

in the various industries. Table 2-2 shows

the total in each industry and the number of

these which are less than 10 years old.

The chart shows that those industries

which have made the greatest technological

advancements during the years 1958 - 1968

have the largest percentage of new measuring

machines. Typical is the Communication and

Electronic Equipment Industry and its development of microcircuitry.

The cost of a coordinate, contour measuring machine during that period averaged approximately $35,000 - the total cost for that

10 year period was $216,000,000 or approximately $22,000,000 per year. In 1974, the

cost of only the basic coordinate measuring

machine is approximately $65,000. If it is

equipped with automatic features such as num- erical control (NC), punch cards or tape, and

printed read-out, the cost can increase to $150,000. The sales department of one manu- facturer states that 50% of all measuring

machines are sold with some type of automatic

control and that the median price of all their

sales is approximately $80,000 to $90,000. An official of the marketing department of an- other company, estimates that the median sale

price of their measuring machines is approximately $30,000. This latter company markets

several versions of their measuring machines

ranging in price from $5,000 to $100,000 and

during the past five years has sold approximately 30 per month. This company supplies

approximately 70% of all measuring machines

being bought at this time. Four other com- panies supply approximately 25%, and several

smaller companies fill the needs of the other

5%. These figures indicate that approximately 600 coordinate, contour measuring

machines are being sold year}y. Based on

a median sales price of $40,000, the annual

cost is approximately $24,000,000 which is

a 10% increase in sales compared to the 1958

to 1968 period.

2.2.2.2 The Instrumentation Industry Standard Industrial Classification (SIC)

Although SIC does not allow us to study

in complete detail the national measurement

system for length, we are able to utilize

the classification system to obtain some quantitative numbers on certain types of

20
Table 2-2. Total of coordinate measuring machines per industry.

INDUSTRY

Ordnance

Primary Metal Industries

Fabricated Metal Products

Fabricated Structural Metal Products

Screw Machine Products

Metal Stampings

Misc. Fabricated Metal Products

Machinery (exceot electrical)

Engines and Turbines

Farm Machinery and Equionent

Construction, Mining, Oil -Field

Material Handling Eauipment

Metal working Machinery and Equioment

Special Industry Machinery

General Industrial Machinery and Equioment

Office, Computing and Accounting Machines

Misc. Machinery (exceot electrical)

Electrical Machinery, Equipment and Suoolies

Electrical Equipment

Household Apoliances

Conmunications and Electronic Equioment

Transportation Equioment

Automotive Parts and Accessories

Complete Aircraft

Aircraft Engine and Parts

Ships, Boats and Railroad Equipment

Precision Instruments and Mechanisms

Misc. Manufacturing Industries

TOTAL

instrumentation used in length measurements.

By looking under the alphabetic index of

manufacturing industries in the 1972 SIC

Manual, we are able to classify our particular instrumentation for length in terms of

SIC numbers versus the types of instrumentation already discussed.

Mechanical Class

Measuring instruments, mechanical 3545

Rules and rulers, metal 3423

Rules and rulers, wood 2499

Rules and rulers, printers 3555

Tape measures 3999

Optical Class

Measuring instruments, optical 3832

Microscooes 3832

Electronic Class

Laser scientific and engineering

instruments 3811

Laser systems and equipment 3662

Microwave test equipment 3825

Surveying instruments 3811

Coordinate Gear

Contour Under Checking Under

Meas. Mach. 10 Yrs. Machines 10 Yrs.

497 200

o i / Coo /I Q 97 OO o yo by

77n OU/

1 9'5 LC.6 i i OH oy

59 9 9

1 DR 7K/ 0

1 9 IL

1 A OQ ybo 9 0 c n ybU

ibb c 9 b£

Db 4/ 9 no lUo

.3D 9Q by

Ode CA 0

i / / 10/ ony4 / i 00 bU 1 9'27 /ICC 4bb

Q9 OO C930 9 7

"577 oil 010 Lie. ioy 7Q/o

801 Ill 440 193

216 183 170 78

1ib 9 n 0 u

1 7 552 528 240 98

623 415 1214 388

256 131 553 140

37 37 110 95

303 223 551 153

24 21 323 258 245 106

101 58

8628 6183 9562 3325

The SIC codes should not be considered as

all inclusive but they will serve the purposes of:

(1) a guide to permit us to obtain an estimate for the economic size of an instrument

industry,

(2) a basis for using standard industrial

terminology when we correspond with a com- pany and for updating our data file through

Bureau of Census reports.

We shall now elaborate on one type of instrumentation by making use of the 1963 and

1967 Census of Manufacturers which are ex- haustive studies of industry.

Mechanical Instrumentation : 3545 - This industry comorises establishments engaged in the manufacture of cutting tools, machinist's

precision measuring tools, and attachments

and accessories for machine tools and for

other metalworking machinery. Types of (pertinent) oroducts include:

Calipers and dividers

Comparators (machinist's precision tools)

Gage blocks

Gages except optical: plug, ring, snap.

21
thread, electric, gear, pneumatic

Measuring tools and machines

Micrometers

Optical measuring devices

Scales, measuring (machinist's precision

tool s)

Verniers (machinist's precision tools)

This industry code has been broken down into

further product codes:

Product Code

35452

3545211

3545213

3545215

3545217

3545221

3545261

354571

Description

Precision measuring tools

Comparators

Fixture type-fixed size limit

gages

Thread type-fixed size limit

gages

Adjustable size limit gages

Gage blocks

Dial indicators

Pneumatic gages (manual and

automatic)

3545298 Other machinists precision tools

including micrometers, calipers and dividers

35453 Other attachments and accessories for machine tools

3545351 Toolroom specialties, including

levels, angle irons, plates,

squares, sine bars, V-blocks,

flats, etc. We have obtained information for SIC code

3545 from the 1972, 1967, and 1963 Census of

Manufacturers published by the Bureau of the

Census and the Commerce Department. Table

2-3 shows that values of shipments for the

Machine Tool Accessories Industry (3545) in 1972 totaled $1226.9 million. This amount

included shipments of machine tool accessories and measuring devices (primary products)

valued at $996 million, shipments of other

products (secondary products) valued at $157

million, and miscellaneous receipts (mainly

products bought and sold) at $74 million.

Table 2-3. Industry-product analysis for the machine tool accessories industry (SIC 3545).

Value of blilpnieiUs Value uf primary product slilpments

Census

Year Total

($ millions)

Primary products

($ millions)

Secondary

products

($ millions)

Miscellaneous

receipts

{$ millions)

Primary product specialization

ratio

Col. B Col. B + C (percent)

Total made in

.ill industries

($ millions)

Made in this industry

($ millions)

Made in other industries

(S millions)

A B C D E F G H

1972 1226.9 996.0 156.9 74.0 86 1122.0 996.0 158-0

1967 1309.9 1035.9 176.2 97.8 85 1222.4 1035.9 186.6

1963 787.3 616.0 121.8 49.5 83 731.7 616.0 115.7

1958 511.4 401.7 73.3 36.4 85 470.1 401.7 68.5

Table 2-4. General statistics for the machine tool industry.

All em jloyceg Production workers

Ytar

lodujtry or product

clane codt Industry or product clatB by spBclalleaclon EatabllahaenCG

CnuBb.!rt) Total

(1000) Payroll (nllUong)

Total

(1000) Man-hou ra (1000) WaRea(nalllona)

Valua addad

hj Banufaccure

ad lusted t»UUona)

Value 0/ ahlpnenta

(lallUons)

1972 3545 MacKijie Tool AcceaeorleB 1210 t6.0 50.1 35.

1

66.1 290.5 861.1 1226.9

1967 35«J Machine Tool Accaaiorlaa lltl 60.3 479.3 45. 2 96.4 324.2 922.8 1309.9

1963 3S«S rUchlna Tool Accaaaoriaa 1031 40.9 312.

B

34.4 72.0 208.1 559.3 787.3

1963 3:«32 FTtclaloQ Haaaurlnf Tool* IIJ J.* 35.4 4.0 S.S 23.] 55.4 74.2

22
The value of the primary product of an industry is summarized in columns F, G, and H. Table 2-4 presents some general statistics

for the machine tool accessories establishment,

Table 2-5 contains informative data on the

numbers of mechanical measuring instruments

which are within the national measurement sys- tem for length. We are able to obtain current figures for the industry by consulting

the Annual Survey of Manufacturers 1971 - M71(AS)-2. The total figures for SIC 3545

and SIC 35452 are shown in table 2-5. It

is interesting to note that the percentage

ratio of precision measuring tools to machine tool accessories has fluctuated within

3% over the past 13 years. Table 2-6 shows

that when the figures are adjus,ted for a 7%

yearly inflation rate, the machine tool

industry had a negative growth of 38%.

2.2.3 Reference Data

2.2.4 Reference Materials

Neither reference data nor materials play

a substantial role in this part of the National Measurement System. Exceptions do occur, e.g., the "North American Datum" described in Appendix G.

2.2.5 Science and People

NBS and other National Laboratories can routinely measure end standards to one part

in 10~6 with an uncertainty of approximately

.05 micrometers. This accuracy is far better

than the machine tool industry can use. Our

contacts with production and quality control

engineers within the industry including

those involved in precision instrumentation

indicate that they all would be extremely

happy if they could get an "honest tenth"

(the ability to machine a part and measure

it to .0001 inch, 2.5um). The inability of

most quality control departments to measure

within .0001 inch is usually due to the personnel rather than the measuring equipment.

Some of the newer comouter and numerically

controlled (NC) machines are caoable of

achieving a "tenth" if the proper precautions

are followed such as compensating for tool wear and thermal distortions of the machine

and work piece. In view of this the primary

research in extending the state-of-the-art

Table 2-5. Value of shipments for SIC 3545.

Product

Code Product

Total Shipments, Incl . Interplant Transfers

(mil 1 ions of dol lars)

1972 1967 1963 1958

3545 MACHINE TOOL ACCESSORIES AND

MEASURING DEVICES 1226,.9 1309.9 787,.3 511,.5 35452 Precision measuring tools 94 .3 130.8 87,.9 60,.9 Machinists' precision tools:

35452 11 Comparators 6,.1 16.1 8,.8 7,,2 Fixed size limit gages (American

Gage Design type -C-S8-51):

35452 13 Fixed type 7 .0 8.9 7,.0 3.,9 35452 15 Thread type 4,.3 9.4 6,.0 6,.1 35452 17 Adjustable size limit gages 5,.8 4.6 2,.8 1

,

,8 35452 21 Gage blocks 1,.9 4.0 2,.6 1,.9 35452 61 Dial indicators

^ 11,.7 9.9 6,.6 4..7 35452 65 Micrometers and calipers 9,.0 9.4

35452 71 Pneumatic gages (manual and automatic) 13,.3 23.3 14,.5 35452 98 Other machinists' precision tools,

27,,1 including micrometers, calipers and

di viders 28,.0 36.1 36,.8 35452 00 Precision measuring tools, n.s.k* 7 .2 9.2 3,.0 8,.2 35452 51 Toolroom specialties, including levels

irons, plates, squares, sine bars.

V-blocks, flats, vises, etc. 24.7 11 .8 7,.1

For the 1963 code 35452 65 "Micrometers and calipers" was included with code 35452 98 "Other

machinists' precision tools."

*n.s.k. - not specified by kind.

23
Table 2-6. Shipments of products and services of several industries.

MACHINE ELECTRONICS CHEMICAL OILFIELD MACHIN.

TOOLS COMPUTER INDUSTRY AND EQUIP.

SIC 3541, 3542 SIC 3573 SIC 28 SIC 3533

SHIPMENTS^ SHIPMENTS SHIPMENTS SHIPMENTS

ADJUSTED ADJUSTED ADJUSTED ADJUSTED

YEAR FOR 7% FOR 7% FOR 7% FOR 1%

INFLATION INFLATION INFLATION INFLATION

1967 2,841 2,841 3,761 3,761 42,148 42,148 800 800

1968 2,817 2,633 . 4,163 3,890 45,622 42,637 906 847

1969 2,835 2,476 5,112 4,465 48,269 42,160 989 864

1970 2,598 2,121 5,700 4,653 49,355 40,288 1057 863

1971 2,019 1,540 4,952 3,778 51,873 39,574 1053 803

19721 , . 2,270 1,618 5,546 3,954 57,437 40,952 1140 813

I973I . 2,550 1,699 6,210 4,138 63,200 42,113 1230 820

I974I , 2,850 1,775 6,690 4,166 68,200 42,471 1325 825

% 7 yr . growth -38% 10.8% 0.77% 3.19%

Estimated by Bureau of Comoetitive Assessment-BCABP-US Department of Commerce.

Data from US Industrial Outlook 1974 - US Department of Commerce, p308.

Value of shipments is in millions of dollars.

in length measurements is being done at the

National Laboratory level. At NBS a con- tinuing effort is being made by engineers

and physicists to design equipment and methods to measure lengths to 1 part in 10"'.

The most promising device to achieve this

is the laser. Special purpose laser interferometer systems have been designed that

appear, at this time, to have achieved this

goal. The scientific community, universities, and pure research laboratories are generally only interested in improving the

values of the physical constants such as the speed of 1 ight (c )

.

The c measurements in this field are so widely and so commonly made that no useful

generalizations about the people doing them

can be made.

2.3 Realized Measurement Capabilities

The reader must be warned of the difficulties of using the terms "accuracy" and

"precision" to characterize an instrument or what is needed by industry, etc. If the systems analysis approach of viewing a measurement is used, then the entire process must be

examined which entails:

(1) the end result of that measurement,

(2) the environment in which the measurement is made,

(3) the instrument used in the measurement

process

,

(4) the operator making the measurement, and

(5) the interpretation of the data.

For this reason unless a measurement process

has been proven to be in statistical control,

the significance of the measurement is not

clear. And to prove that a process is under

control, continual and extended monitoring

of that process must be maintained and this

does not happen overnight. For these reasons

it is very difficult to obtain meaningful

numbers which are representative of what

industry needs in terms of accuracy because

many industries do not even know what they are caoable of measuring at "this point in

time". The numbers used to derive figures

2-12 through 2-19 and table 2-7 were found in pertinent publications in the area of interest and generally agree with those obtained

from various industrial sources during the course of this study.

Table 2-7. Typical NBS working accuracies

for angular standards.

Angle blocks

Angle generators

Indexing tables

Optical wedges

Polygons

0.35 sec 0.15 sec 0.25 sec 0.25 sec 0.35 sec

24
10 5 10

10

10

° 10

10

10

10

This figure is the result of scanning various publications, and educated guesses as to the current accuracy of linear length measurements for the aerospace industry.

10

10

-6

accuracy

(inches) 10

10-3

10

-2

10

,-3 10 10" 0 " 10 10 10

" Length (inches)

Figure 2-12. Best routine accuracy for end

standard measurements at NBS.

1 10 10 10 10 distance requirements (inches)

Figure 2-13. Linear length measurement capa- bilities in the aerosoace industry.

-4

10

m

<u -3 ^10

uU

3U

O

cd

10

-1

1 10

size (inches)

10

lO"" I 10 lO' lO' 10* lO' RANGE (meters)

Figure 2-14. Linear length measurement capa- bilities in the ball and roller bearing industry.

Figure 2-15. Characteristics of typical

ranging devices novi available.

cnc

eu

•H /—

3 03 C d)

Q)U U

c

CI

tou

3

ooa

10

10

-3

10 1 10 10^

distance requirements (inches)

10

-6

10

ou

3V

o

10

-4

10

-3

10

-1

1 10 10

range (inches)

10"

Figure 2-16. Accuracy requirements for in- Figure 2-17. Accuracy requirements of metrol

tegrated circuit camera. ogy.

25
-6

10

01 -5 ^10

o

c -4

•A 10

>> -3

oo

10 1 10 10

range (inches)

10"

Figure 2-18. Accuracy requirements of photogrammetry

.

Figure 2-13 is the result c scanning various publications and educated guesses as to the current accuracy of linear length measurements for the aerospace industry.

It is quite difficult to find meaningful

accuracy statements by the industry but fig- ure 2-14 is a sampling from some current bearing manufacturers via catalogs.

The results of several measurement audit

surveys provide much illumination regarding

the true state-of-the-art of realized meas- urement capabilities for length and related

dimensional measurements.

In 1961 the National Physical laboratory

(NPL) investigated the current accuracy

of industrial measurements in the size

range from 0.02 inch to 5.0 inches. About

forty firms in England were invited to par11 13 15 17 19 21 23 25 27 29

240

220

No of Chip

Averages

M//3

5•H 200 —

(Uc

-> 190

170

150

Nominal 200u" lines of a standard plate were measured on three different measuring

machines. The average of each sequence is marked along the ordinate. Deviations of

up to 40p" have occurred. The results confirm the need for calibration of measurement

systems to an independent (certified) standard. Since each point represents the av- erage of four readings, curves based on single measurements will be less precise.

Figure 2-19. Results of measuring masters on three different measuring machines for integrated circuit industry.

26
4

3

-

2

ticipate in the survey and as many branches

of the engineering industry were embraced 5xio- as were likely to be interested in measurements in the range chosen. No similar

comprehensive study of measurements has ever

been undertaken in this country at the inspection and workshop level. However, we ex- pect the English results to be generally indicative of the situation in this country.

In some cases the conclusions and results are eye-opening, considering that in most cases _

gage blocks were used as reference standards. ^

The artifacts were manufactured by NPL and g

^ consisted of 0.02, 0.04, 0.15, 0.4, 1.0, 2.5, ~

and 5.0-inch external diameter plugs. Rings i q were made with internal diameters of 0.04, 5

0.15, 0.4, 1.0, 2.5, and 5.0 inches. The

artifacts were of hardened steel and measured

to accuracies of 10 to 20 microinches by NPL. The difference between the industrial measurements and those made at NPL were calculated for each firm. To obtain an idea of

the spread of the industrial measurements,

values of the standard deviation for a particular diameter were plotted. In figure 2- 20 the curves show that external measurements

are more accurate than internal measurements

but become less accurate with an increase in

size. Measurements made by inspection departments differ very little in accuracy from

workshop measurements on external diameters

but on internal diameters are more accurate.

The occurrence of large errors is rarer in internal the. external measurements than in the in- external ternal measurements.

It is interesting that in the same study

an empirical formula was developed to exoress Figure 2 the accuracy of these industries for measure- ation of

ments: ments.

INSPECTION

- -

- X

*

—

WORKSHOP

DIAMETER (INCHES)

20. Survey by NPL. Standard deviindustrial errors from NPL measureEquations for Standard Deviation

(Unit 0.001 Inch)

Inspection Workshop

External 0.10 + 0.34 d 0.10 + 0.050 d Internal 0.25 + 0.005 d 0.25 + 0.021 d where d is the diameter in inches.

Commercial comparators were available in 1961

which could easily measure parts to an accuracy of 5 microinches but it is evident that

industry was losing 100 microinches or more

in the measurement process. The summary said

that "main error lay in the inability to transfer size from a master set of calibrated

slip gages to circular parts in the form of

work-pieces ..." Recent NCSL Audit : The National Conference of Standards Laboratories was established as a nonprofit organization of laboratories to coordinate and discuss mea- surement problems. The labs participate in

sending audit packages around every few years

to "check" on various capabilities.

We have analyzed the results from the

latest survey and even though the survey is not complete we will show the results for ten participating organizations. The results

have to be placed within their proper perspective because they tend to emphasize a number (the uncertainty) and not the whole

process. The organizations include:

(1) A laboratory in the automotive field

(2) Standards laboratory (space vehicle

field)

(3) Manufacturer of precision instrumentation

(4) Manufacturer of aircraft

(5) Manufacturer of industrial equipment

(6) Manufacturer of electrical equipment

and comoonents

(7) Army standards lab

(8) Air Force standards lab

(9) Manufacturer of electrical instruments

27
(10) Manufacturer of aviation components

and systems.

The artifacts which were sent to these

organizations consisted of the following:

(1) Two 0.2 inch gage blocks of one type

(2) Two 0.2 inch gage blocks of another

type

(3) Two 4.0 inch gage blocks

(4) One 24.0 inch gage block

(5) Two 1.8502 inch internal ring gages

(6) Two 2.0000 inch internal ring gages

(7) Two 0.0625 inch diameter master balls

(8) Two 0.1250 inch diameter master balls

(9) Two 5 degree angle blocks

(10) Two 15 degree angle blocks.

Instructions were given to "measure each

item listed to the highest accuracy available within your activity." Figure 2-21

shows the measurement results for one type of

a 0.200 inch nominal gage block with the mea- surement uncertainty estimated by each participating organization. Figure 2-22 shows

the results for aa 2.0000 internal ring gage.

The small circle in each bar indicates the mean of the measurements and the shaded area

is the uncertainty of NBS measurements which

must be considered as the standard to which

all others are compared. The measurement

data for No. 1 Ring of figure 2-22 shows

that laboratory No. 42 has good precision

but poor accuracy while laboratories Nos. 38 and 74 show neither precision or accuracy.

Figure 2-23 are results for a master steel

ball. The capability of various labs for

measurement of angle is depicted in fig- ure 2-24.

Table 2-8 is a tentative summary of the

results of these measurements with the fig- ure for standard deviation being computed

from the values reported by each participant.

It is interestina to note that measurements

involving a linear length cause the "least"

amount of trouble while measurements of internal diameters and spherical diameters appear to cause the most trouble. This is similar to the results of the NPL survey and a

2r-

-2

3

- 4

-5

-6

•7

-8

9

10

12

1 1 —

-r 9

0 <J. o

GCU

GCO

I—<

NBS 30 33 38 42 48 54 59 74 76 79

# 51283

9 9

4* 9

NBS 3C 33 38 42 48 54 59 74 76 79

# 52165

Figure 2-21. Recent NCSL survey. 0.2 inch gage blocks showing measured values and estimated

uncertainty for NBS and ten other participating labs.

28
70

60

50

40

30

20

10

0

-10

-20

-30

-40 —

-50 -

-60 -

-70 I I I I I I I I NBS 30 33 38 42 46 54 59 74 76 79

# I RING

NBS 30 33 38 42 48 S4 99 74 76 79 # 2 RING

Figure 2-22. Measurements on internal diameters. 2.000 inch ring gages showing measured

values and estimated uncertainty for NBS and other labs.

-200 -

-190-

-180

-170-

-160 -

-150

-140

-130

-120

-110

-too

-90 I L

I

NBS 30 33 38 42 48 59 74 79

# I

NBS 30 33 38 42 48 59 74 79 #2

Figure 2-23. External diameter measurements. 0.1250 inch steel balls showing measured val- ues and estimated uncertainty for NBS and other labs.

29
2. Op

1.5 —

1.0 —

.5 -

0 —

- 5 —

- 1.0 —

-1.5 —

2.0 —

NBS 30 33 59 74 79

RA- 17

00o

CJ

o

o

-6

I \

I I I I ^ NBS 30 33 38 59 74 79

RA-18

Figure 2-24. 5 Degree angle blocks showing measured values and estimated uncertainty for

NBS and other labs

.

Table 2-8. Results of partially completed

audit among industrial/government labs with

computed standard deviation for all results.

Standard

Item Identification Deviation

Gage Blocks

0.2 inch #51283 1.6yin.

0.2 #52165 3.1

0.2 #4620 ; 2.5

0.2 #4671 ' ' 2.2

4.0 ' #4852 ! 16.3

4.0 #4866 ,. 15.3

24.0 55.4

Internal ' 1 Ring Gages

1.8502 inch #1

' 26.4yin.

1.8502 #2 27.0

2.0000 #1 32.9

2.0000 '#2 30.9

Master Balls \

j 0.0625 inch #1 ' 30.6Min.

0.0625 #2 23.5

0.1250 #1 29.2

0.1250 #2 26.7

Angle Blocks

5.0 degree #1 2.6seconds

5.0 #2 2.5

15.0 #1 1.1

15.0 #2 1.2

survey of the Aerospace Industry Association

(AIA).

It is evident from looking at the results

of some recent "round-robins", table 2-8,

that the claims of industry to measure accu- rately objects other than simple end standards are optimistic. Even though gage blocks

are available in accuracies of a part in 10^,

not many industrial labs have the capability

to transfer these measurements to other artifacts with great precision and accuracy.

The precision of instrumentation today

far outpaces the capability of personnel to utilize these devices fully in accurate dimensional measurements. In many cases accurate dimensional measurements are only needed

to satisfy functional requirements e.g. to ensure that mating parts will fit properly

at assembly.

Often the industrial contacts which we have made yielded no earth-shattering news concerning needs for more accuracy. The main

area of concern was need for more help with

the day-to-day mundane problems. One solution to this problem is to publish more articles in journals describing the measurement

philosophies of NBS and to describe in greater

detail the various measurement processes.

The main area of impact which new instrumentation is having in dimensional measurements is in the surveying field. Tapes are

still used quite extensively in the industry,

mainly by private individuals, but in the

30
past year or so low cost electronic distance

measuring devices have been revolutionizing

the surveying industry. With these devices

surveyors can measure distances of over one kilometer with accuracies limited only by

their ability to determine the atmospheric

corrections

The computer has proven to be a valuable

tool in the area of inspection and quality

control. If tied into an automatic gaging

system, the computer can print out the inspection result of every part. The comouter

is also a valuable tool for sampling and control. The process can be set up so' that if

the production process is under control, no action will be taken, but if a parameter

changes, corrective action may be taken.

The computer can also be a vital tool in

the use of coordinate measuring machines. As the artifact is probed, the computer can compare the dimension measured against a nominal

dimension and record the deviations.

In the past few years numerical control

for manufacturing orocesses has been increasing. The impacts which NC has upon dimensional measurements are:

(1) 5% savings of direct labor cost from NC machine for improved accuracy

(2) 30% savings of inspection costs due to improved process repeatability

(3) 80% or more of actual inspection time

can be saved through NC insoection over manual methods.

Many manufacturers claim that the resolution of their units may be within 50 or 100

microinches. Not many machine tools can produce to these accuracies. There are screws,

lead screws, beds, ways, spindles, and columns made of metal and subject to tolerances.

All of these play a role in determining the

final machining capability which is the one parameter of primary concern. Thus it behooves the user to know what can be obtained

from his machine.

From communication with various industrial concerns we have seen that the need of industry for the next three to seven years in

dimensional measurements is in the area of

better measurements in three dimensions.

There are many measuring machines on the market today but most of them have the fault

that inaccuracies are defined in terms of one

axis. There is no assurance that if you start

at Doint (1,1,0) and terminate at point (0,0,1)

in a working volume that your inaccuracy can

be expressed as linear combinations of the

individual axis errors. What is needed are methods to characterize these errors. (This

is under development now at NBS with the 3 dimensional facility.) One of the main purposes of the study of the National Measurement System is to find efficient means to disseminate our work to the people who need

it as our oroject progresses.

2.4 Dissemination and Enforcement Network

2.4.1 Central Standards Authorities

Organizations which deal with measuring

systems are classified into either scientific metrology or legal metrology. The scientific metrology category watches over the

values assigned to particular units and maintains the definition of certain standards.

The recognized international authority on weights and measures is the International

Bureau of Weights and Measures which was es- tablished as a result of the Treaty of the

Meter. Legal metrology organizations are

set UD to deal with the legalities of measuring devices and their usage. The recognized international authority here is the

International Organization of Legal Metrology

whose functions include:

(1) Translation of regulations existing in different nations.

(2) Establishment of a plan for the inspection and checking of measurement instruments.

(3) Promotion of closer ties between various

facilities responsible for legal metrology.

Since the desideratum of any unit is precise availability for the user, the adoption

of a specific wavelength of visible radiation

has extended the number of commercial /industrial laboratories in possession of the unit.

Although it might be theoretically conceivable that all products used in manufacturing

and inspection could be checked against basic

measuring standards, it is not at all practical. The obvious solution is to use the primary standard for calibration of secondary

standards, then disseminate the secondary

standards to a large number of scientific,

industrial, and military laboratories whereby a reliable link can be created between

the basic standards and the instruments used

for measurements of industrial products.

In the case of length, the embodiment of

e unit within the physical system is the

Kr lamp. The most fragile link in the

chain is the transfer from the wavelength

standard to "physical" standards or material

artifacts. This first transfer usually oc- curs in the international laboratories around

the world: Bureau International des Poids et Mesures (France), National Physical Laboratory (Great Britain), Physikalisch - Technische Bundesanstal t (West Germany), National

Bureau of Standards (USA), etc.

2.4.2 State and Local Offices of Weights

and Measures

The capabilities of the states' Weights & Measures Laboratories in the area of dimen31

sional measurements are shown in Appendix E. Figure 2-25 shows examples of the type of

length standards supplied to the state laboratories by NBS Office of Weights & Measures . The National Conference on Weights and

Measures, composed primarily of state, county,

and city weights and measures officials, meets

annually to consider problems arising in weights and measures administration and en- forcement.

The National Bureau of Standards Office

of Weights and Measures cooperates closely

with the conference Committee on Specifications and Tolerances to set up regulations

for commercial measuring devices. The re- sult of this is NBS Handbook 44 which contains codes to meet the changing conditions of trade and the new developments

of the equipment industry. In the area of length measurements, the categories

covered in Handbook 44, are linear measures, fabric-measuring devices, wire

and cordage-measuring devices, taximeters, and odometers. (See Appendix B).

2.4.3 Standards and Testing Laboratories

and Services

The National Conference of Standards Laboratories (NCSL) is a non-profit organization

of laboratories which coordinates and discusses problems in measurements among its

members. An NCSL committee formulates voluntary standards of practice, studies the

calibration needs of science and industry,

conducts measurement agreement comparisons,

and holds periodic workshops and conferences.

The calibration capabilities of various NCSL

members and laboratories in the area of dimensions are published annually (see Appendix F).

The Primary Standards Laboratories of

Department of Defense calibrate the gages

and the standards of the Secondary Standards Laboratories against their master

gages which in turn were calibrated against

the national artifact at NBS. The DoD

Secondary Standards Laboratories calibrate all the standards, including micrometers, plug and ring gages, thread gages,

etc., of the roving or mobile laboratories.

The mobile laboratories calibrate the operating equipment in situ.

As a check on the calibration link between

NBS and the mobile laboratories or field laboratories, the Primary Standards Laboratories

circulate an audit package of a standard, i.e.

a set of balls. All the laboratories in the

calibration chain including NBS calibrate

this package using their customary calibration technique and process. If the results

of any one of the laboratories differ from

that of the others or NBS, it shows that the

technique or process is out of control and

steps are immediately taken by that laboratory to correct it.

Detailed fiscal data for just one of the

services are represented: The annual operating budget for the U.S. Army Metrology Calibration Center is approximately $6.5 - $7.0

million. The cost of in-place equipment for

length measurement represents 3.6% of this

annual operating cost. The operating cost

(salaries, overhead, etc.) for length measurement represent 2.2% of the total so that

dimensional measurements represent approximately 5.8% of the Army Standards Lab operating budget [3]

2.4.4 Regulatory Agencies

Regulatory agencies are not really relevant to this field.

2.5 Direct Measurements Transactions Matrix

2.5.1 Analysis of Suppliers and Users

The matrix, table 2-9, was formed using

twenty selected customers and users of NBS

length and related measurements. It is

modeled after the Input-Output (I/O) matrices used in the field of economics, and

will often be referred to here as the "I/O

Matrix." The lack of information relating

to the interaction between the suppliers and users is due to the difficulty in obtaining

meaningful data. For example, how much of

the measurement output of the steel industry

is used in the aerospace industry is probably not reliable and not very relevant to a study of NBS length and related measurements.

Some of the data are what one would expect,

e.g. DoD, the machine tool industry, the aero- space industry and the precision instrument

industry are heavy users of NBS length mea- surements. However, there are some surprises.

The chemical industry and the petroleum industry are also heavy users, but the auto

and truck industry and the auto parts industry are not.

2.5.2 Highlights Regarding Major Users

The following paragraphs relate the various industries to the National Measurement

System and show how their technologies depend

upon a viable connection to it.

2.5.2.1 Air Frames, Engines, Aircraft Equipment, Guided Missiles, and Space

Vehicles and Parts

We can characterize this user as the aerospace industry with SIC codes 3721, 3724,

33
Table 2-9. Direct measurements transactions matrix.

DIRECT MEASUREMENTS

TRANSACTIONS

MATRIX FOR LENGTH AND RELATED

DIMENSIONAL MEASUREMENTS

U

s

ER

S o «

_j 5 oss

1

<C «£ Z 1 O

K- (J

CC o UJ oc

2

0:s

>- lO

Q- t—

«x -rt—

7T

OQ-OC Qt/lO

3

^

PRECISION

INSTRUMENTS

o

I—UJXLJf

(/I CQZ

6

STATE

S

LOCAL

-J

OFFICES

OF

WEIGHTS

i

MEASURES

DoO

&

PRIVATE

°°

STANDARDS

LABS CO 1/1 <x <t Q -J UJ

U_ QC _CL ^3- UJ —

X QC h- Q- O '

9 o

PETROLEUM

INDUSTRY

-

MACHINERY

GENERAL

^

AEROSPACE

AND

~

AIRCRAFT

INDUSTRY

AUTO

AND

TRUCK

w

INDUSTRY

^

OTHER

TRANS.

EQUIP.

*

R.R..

MARINE.

ETC.

^

CHEMICAL

INDUSTRY

_

ELECTRICAL

AND

ELECTRONIC

INDUSTRY

FERROUS

AND

NON-

-;

FERROUS

METAL

INDUSTRY

RETAIL

STORES,

SUR-

~

VEYORS.

Er.GiriEEPS,

ARCHITECTS.

ETC.

S

FOREIGN

COUNTRIES

S

GENERAL

PUBLIC

' KNOWLEDGE

SUPPLIERS \ COMMUNITY X X

1 0

0

^ 0

1 1

0

» E

1 1 O^E

1 1

0 ^E

1 1

1 0 E

1 1

0

^ E

1 1 1 Q E

2 1

1 3 E

X

1 1

1 0 D

2 INTERNATIONAL METROLOGY LABS

X 2 1

0 ^A

2 2 0^

2 1 2 0 A2 1 13 1 2 1 0 AO A

4 1 3

2 B

4 1 2^

3 DOCUMENTARY SPECIFICATION

ORGANIZATIONS

1 u

0 D

2 2

0

^ D

2 1 2 0 E2 1 12 1 2 2 0 0 0 D2 1 3 : 0^

3 1 0^3 1 oS

2 : 0^

2 1 2 0 D

2 1 2 0 D2 1 2 0 D2 1 2 0 D

2 1 2 0 D2 1 2

0 D

4 PRECISION

INSTRUMENTS

1 1

1 0 F

2 1 2 0 C2 1

1 0 D

2 12 1 4 2 0 A |0 A3 1 2 0 E

2 1 2 0 A3 1 3 0 C2 1 3 0 A

1 1

1 0 C

2 : 2 0 C

1 1

1 0 C

2 1 2 0 C2 1 4

0 C

2 1 1

0 C

5 MACHINE TOOL

1 1

1 0 C

2 1 2 0 c2 1 2 0 E2 1 2 0 E2 1 4 0 A

2 1 3 0 E2 1

1 0 c

2 1

1 0 C

2 1

1

3 C

2 1 1 0 C

2 1 4 0 C2 1 4

0 C

2 1

3 0 C

2 1 1 0 C

2 1 2 0 C

2 1

1

3 C

6 N8S

1 1

0

; D

3 1 4

0 B

2 1 2

2 D

3 1 3 0 B3 1

A^

2 B

2 1

0 A

3 1

1 0 B

3 1 4 0 B3 1 3 0 B4 1 4

2 B

3 1 3 0 B3 1 3

N B

3 1 1 N B

1 1

1 0 B

3 1 3 0 B

3 1 3

2 6

3 1 a

3 B

3 1

1

M B

3 1 1

2 B

1 1

1

3 B

7 STATE & LOCAL OFFICES OF WEIGHTS & MEASURES

2 1 2 0 E1 1 2 0 A2 1 1 0 E2 1 2 0 A

2 2

2 0 B

3 2

3

3 B

3 1

2

3 B ^ DoD & PRIVATE STANDARDS LABS

1 1

1 0 E

2 1 2^2 1 0^2 1 oS3 2 0^

2 2 i2 2

2 1 4

0 B lO B

2 2 0^

2 1 2 0 B

2 1 2

0 B

2 1

2 0 B

' OTHER FED. LABS

(PRIMARILY NASA)

1 1 1 1 0 E 1

2 1 |2 1 2 ' 1 0 E 10 B

2 1 I 0 B3 1

2 0 B

2 1

1 0 E

2 :

1 0 A

3 X

2

0 B

2 1 1

3 B 10 PETROLEUM INDUSTRY

3 1 2 0 E2 1 2 0 D 'l'

0 0

^ 3

^

0 D P

2 1 1 b D

2 1 1

3 D

2 1 1

3 P MACHINERY

GENERAL

2 1 2 0 E2 1 2 0 E2 1 2 D E

1 1

1 0 E

2 1

1 0 E

2 1 ]2 I

3 4

3 E !0 A

2 I

2 0 E

2 1

2 0 E

2 1

2 0 E

2 1

2 0 E

2 1 J

0 E 12 AEROSPACE AND

AIRCRAFT INDUSTRY

1 1

1 0 E

1

1 1 2 2 1 2 0 E

p 1 2 0 E

2 1 2 0 E

? 1 2

3 E

2 1 2

3 E

1 I 2 0 E

1 1 3 0 A

2 1 2 0 E2 I

2 0 E 1^ AUTO AND TRUCK

INDUSTRY

?

1 2 0 E2 1 2

0 E

^ 2 D E

2 1 2

0 E

1 i

2 0 E

1 1

3 0 A

2 :

2 0 E

2 1

2 0 E

2 1 2 0 C OTHER TRANS. EQUIP.

R.R., MARINE, ETC.

?

1 2

0 E

1 1

1 3 E

1 1

3 0 A

2 1

2 0 E

2 1 2

0 C 15 CHEMICAL INDUSTRY

? 1 1 b E

2 1 2

0 E

1 1

3 0 A

?

16 ELECTRICAL AND

ELECTRONIC INDUSTRY

? 1

0

^ E L%

2 1 2 D E

3 1 3

2 E

2 1 2

3 E

2 1

1 D C

2 1 2 0 C2 1 2 0 D2 1 2 0 C1 1 3 0 A

2 : 2 0 C

t

1

1 0 D 17 FERROUS AND NON- FERROUS METAL

INDUSTRY

^ 2 b E

} 1

1

3 E

2 1 1 0 D

2 1

1 0 D

2 a

2 0 D

2 1 2 0 D2 1 2 0 D1 I 2 0 A

X

18 RETAIL STORES, SUR- VEYORS, ENGINEERS,

ARCHITECTS, ETC.

> 1

1

3 E

1

D E

2 1 1 b E

2 1 2

D E

2 1 3

0 A

2 1 4 0 A

19 FOREIGN COUNTRIES X ^ 1 3

0 E

1 1 1

3 £

1 1

1 D E1

3 A

3 1

2 0 B

1 1

1 0 C

2 1 2 0 C

X 2 I1 0 A 20 GENERAL PUBLIC

I 1

1

3 E 1

3 E

2 1

1 n E

i i 1 1

C - IMPORTANCE OR CRITICALITY OF TRANSACTIONS

1 = Purely matter of convenience

2 ' Economically compelling; strongly desirable

3 ' Legally required, alternate sources unsatisfactory

4 » Hatter of life & neath; sole source; essential

B - RATE OF CHANGE

N • Declining volume or needs

0 - Stable

2 • Growing

4 " Explosive growth or discontinuity on hand

KEY TO MATRIX ENTRIES

A - MAGNITUDE

0 » Trivial

1 Minor

2 • Moderate

3 Important

4 » Major

7 Don't know

X • Exluded from study

D - (IN)ADEQUACY OF TRANSACTION SERVICES

0 = No forseeable improvement needed

1 = Under control

2 - Marginally OK

3 = Seriously deficient

4 Out of control

- TYPE OF TRANSACTION

A = End use measurement data

B ' Other mcas. services (e.g. calibrations)

C = Measurement instrumentation & associated

software

D = Measurement "how-to" info

E • Measurement "needs" Info

34
3728, 3761, 3764, and 3769. In the matrix,

table 2-9, sector 12, Aerospace and Aircraft.

3721 - Establishments primarily engaged in manufacturing or assembling complete aircraft.

3724 - Establishments engaged in manufacturing aircraft engines and engine parts.

3728 - Establishments primarily engaged in manufacturing aircraft parts and auxiliary

equi pment.

3761 - Establishments primarily engaged in manufacturing complete guided missiles and

space vehicl es

3764 - Establishments primarily engaged in

manufacturing guided missile propulsion

units and propulsion unit parts.

3769 - Establishments primarily engaged in

manufacturing guided missile and space ve- hicle parts and auxiliary equipment.

Examples of users:

(1) In the inertial guidance system manufacturing process critical tolerances are placed

upon the subassemblies. The gyroscope (gyro)

rotor (ball in fig. 2-26) is suspended within

an enclosure by static levitation and its cen- ter of mass is displaced from the geometric

center. The rotor spins on the center of mass and its geometric center rotates about

the center of mass in a circular plane perpendicular to the rotation. This mass/geometry center imbalance causes a sinusoidal

voltage signal to be produced across opposite

plates of the cavity. A 12 millionths of an inch displacement between the centers oro- duces a signal resolvable to one oart in ten thousand. Four such sine signals are produced by the cavity which give different

phase angles and thus result in the gyro

pointing signal

Imperfections in the spherical geometry

of the cavity and rotor affect directly

the accuracy of the gyro. These imperfections can be corrected but usually airborne

computer capacity is not large enough to ac- commodate all error analysis. During functional testing the gyro system "tests" the

spherical perfection of these parts with a sensitivity beyond the ability of the manu- facturer to measure dimensions. A special

device for measuring these dimensions was constructed with a stated measurement sensitivity of 1 X 10"' inches, but the manufacturer's gage blocks calibrated at NBS failed

to support the measurements.

(2) Jet engines periodically undergo extensive overhauls in which they are comoletely

disassembled and examined to determine suitability for re-use. Jet engine blades are subject to extremely high stresses, and defects, such as cracks, can increase stress

effects by many orders of magnitude. A typical jet engine contains over 1500 com- pressor and turbine blades. A current technique for automated inspection of these blades

can detect cracks exceeding the design specification of 0.0005 inch wide by 0.002 inch

long by 0.002 inch deep.

CENTER OF MASS

GEOMETRIC CENTER

CAVITY SPHERICITY

ROTOR SPHERICITY

CENTER OF MASS (AXIS OF ROTATION)

GEOMETRIC CENTER

PATH OF THE

CENTER OF MASS

PATH OF THE GEOMETRIC CENTER

Figure 2-26. Example of dimensional measure- ments needed by aerospace industry.

35
Current Capabilities : In the period 1955-

1964, the role of "accuracy" became disguised

as a kind of culprit. Startling and expensive crises in industry developed - unprecedented rejection of products and system failures. In one case a series of failures in airborne hardware assemblies was traced to close cylindrical fits having a history of

inconsistent measurement of component inside

diameters. In another case a gyro producer

found rejects soaring to 70% with a loss of

thousands of dollars. In another plant failures in testing complex missile subassemblies

ran into millions of dollars and were traced

to a complex contour which was subject to measurement errors.

In recent years the mass production of

modern ultra-precise equipment for measuring

has become widespread. But in 1958 an Aerospace Industries Association (AIA) survey

disclosed "variations totaling over 80 microinches on an identical inside diameter of a sample part, as measured by six of the most

competent laboratories in the country, or 80 times the accuracy of the best gage block

measurements of the period, with the best

laboratories of the government and the gage

manufacturers unable to agree to better than

70 microinches" . A later AIA survey revealed

that 44% of companies (reoresenting 80 of the

nation's most advanced firms) reported insufficient measurement accuracies on internal

diameters below 0.250 inch.

Figure 2-13 (section 2.3) shows the ac- curacy requirements of the aerospace industry for their various length measurements,

i.e., for measurement of 1 inch or smaller

the accuracy required ranges from 100 parts/

million to 5 parts/m : 1 1 ion

.

Economic Impact : Current fiscal figures

for the aerospace industry are shown in ta- ble 2-10 from the Bureau of Domestic Com- merce. After serious setbacks in the last

few years, internal cash flows are insufficient to support the high development

costs of new programs.

Foreign manufacturers have under development major projects aimed at the markets of

the late 1970's and early 1980's. In most

cases the new foreign aircraft will have no direct competition from U.S. suppliers. Es- timates of the total volume of airline equipment business in the 1974 - 85 period range

from $55 billion to $148 billion.

2.5.2.2 Ball and Roller Bearings

Establishments primarily engaged in manu- facturing ball and roller bearings and parts

are classified in SIC code 3562. Sector 4,

Machine Tool, in the Measurement I/O Matrix,

table 2-9, includes this SIC category.

Table 2-10. Aerospace:

projections

.

SIC 3761 Complete

guided missiles

economic trends and

Value of Shipments

(bill ions of dol 1 ars)

1974 1980

Industry

Product

SIC 3721 Aircraft

Industry

Product

SIC 3724 Aircraft

engines and parts

Industry

Product

SIC 3728 Aircraft

equipment

Industry

Product

3.950

3.600

11.700

9.000

3.410

3.100

2.700

3.300

5.100

4.700

10.200

8.500

3.240

2.700

3.900

4.900

^includes value of all products and services

sold by establishments in this industry.

2 includes value of products primary to this

industry produced by all industries.

Sample Uses and Accuracies : Bearings are

used in practically all mechanisms which incorporate wheel and shaft operations. The

automotive industry is the principal con- sumer of bearings with farm and construction

machinery close behind. Aerospace and makers

of general industrial equipment also use ball

and roller bearings. Extra-precision bearings are required for gyro applications and

in one commercial version total clearance

gaps are 2.0 micrometers.

Calibrated master balls are used as a standard for measurements of production balls

by the ball bearing industry. The ANS Ball

Standard B3-12-1964 defines master balls as "Master balls shall be made of steel, 64 Rc or higher with permissible diameter variation

of 1/10 of the diameter tolerance per ball...

or 0.000002 inch whichever is larger." Master balls are primarily used in comparator

measurements of other balls which in turn are

used to check production sizes.

Figure 2-14 (section 2.3) shows the accu- racy requirements of the ball and roller

bearing industry which is 100 parts/million

for the smaller balls to 1000 parts/million

for the larger ones.

Economic Impact : Shipments by the ball

and roller bearing industry will climb to $1.5 billion in 1973 and estimates for 1980 are that SIC 3562 will be a $2.1 billion in36
dustry. Demand for high precision in bearings will continue as requirements of the

computer and instrument, aerospace, con- struction machinery, and machine tool ac- cessories become more stringent.

2.5.2.3 Gears

SIC codes 3714, 3751, 3728, 3462, and 3566

refer to gears for motor vehicles, motorcycles and bicycles, aircraft power transmissions, and other power devices which use

gears. Sectors 11 - 12, of the I/O Matrix

Machinery - General and Aerospace and Aircraft. Table 2-9 includes these SIC categories . Today's production gears are expected to function quietly and provide long wear life.

This requires that a gear be checked for dimensional accuracy and also for nicks and

cracks. There are many types of gear checking machines on the market and a typical one

will inspect a gear for size (to 0.0005 inch

tolerance), length (to 0.005 inch), pitch

diameter (to 0.003 inch), eccentricity (to

0.002 inch), and nicks (to 0.0005 inch).

The accuracy needs of today's production

gears are being met adequately by many of

the machines on the market. There are some who feel they have special needs that are not

being met. (The Navy Department requires ex- tremely quiet reduction gears for their nu- clear submarines since the most reliable systems for the detection of submarines rely on sonic detectors. Quiet gears require more

accurate gear tooth profile and better sur- face f i ni sh)

Total value of shioments for all the above

SIC codes for 1971 was $24.2 billion. It has

been estimated that the gear industry com- prises approximately 3 - 6% of that total.

2.5.2.4 Geodetic Investigations

The field of geodetic sciences, for the

purposes of this study, will be considered

to encompass surveying, mapping, geodesy,

photogrammetry , geodetic cartography, cadastral surveying, and engineering surveying

and construction. Sector 18, Surveyors,

Architects, Engineers, of the I/O Matrix

(table 2-9) includes this field.

Construction people use linear measurement

all day long, reaching for a rule, a tape,

etc. For short distances, rules work well

but for long measurements, tapes and electronic distance measuring systems are called

for

To obtain an idea of the number of engi- neer surveyors and land surveyors in the U.S., we contacted the American Congress on Surveying and Mapping in Washington, D.C. In the

United States in 1971, there were approximately 15,300 active professional engineer

surveyors plus some 14,800 land surveyors.

It was estimated that each one uses one measuring steel tape and possibly two or three,

so we have a range of 30,000 to over 100,000

steel tapes in use for land surveying purposes . Accurate geodetic information is needed

by many groups and individuals:

(1) Rural, urban, city, and regional engineers; planning, construction, and surveying

groups

(2) Automated transportation systems and

other activities using addresses from geodetic coordinates.

(3) Federal work, including the surveying

and mapping of the Geological Survey, the

Forest Service, the Army Corps of Engineers,

the Coast and Geodetic Survey and NASA.

(4) Surveys and planning for water resources,

highways, and utilities.

(5) Mining and related engineering surveys.

(6) Scientific uses.

(7) Legal aspects.

Electronic distance measuring (EDM) equipment, ODtical reading theodolites, and small

electronic computers are now commonly used by

engineers and land surveyors. They easily

obtain the needed accuracies ranging from

one part in 10,000 to one part in 100,000,

which requires that the accuracy of the basic

control net (discussed in Appendix G "The

North American Datum" by NOAA) approach one part per mi 1 1 ion

An example of the accuracies of this EDM

in the microwave (1,000 MHz to 10,000 MHz)

region compared to surveyed distances by

other means is shown in table 2-11.

The precision practicably attainable today

in geodetic measurements on the earth's sur- face is about one part per million. This may

well be the limiting engineering precision

on such measurements for the next few years

because this "limit" is imposed by problems

of calibration and use of geodetic tapes

and by the effect of the atmosphere on the

propagation of an electromagnetic wave. The

cost of making a measurement with tapes is three to four times that of the geodimeter

traverse method. It is an easy measurement

in the laboratory where vacuum and air paths

can be readily compared to parts in 108, but

for very long distances, out of doors, the

appropriate meterorological parameters must

be measured at several points to obtain an average value for n to better than 10^. A method for sampling n continuously using a two-color (red and blue) geodimeter, (the

difference between the optical paths observed for the two wavelengths is proportional

to the index of refraction) achieved an ac- curacy approaching 1 part in 10' over distances approaching 10^ meters.

37
Table 2-11. Typical measurements with EDM microwave ranging

device.

RIDGEWAY BASE

Difference

Line Observer Di stance from mean

Whi tehorse-Liddington 1 11260 643 -0 014

Liddington-Whi tehorse 2 11260 653 -0 004

Whi tehorse-Liddington 1 11260 601 -0 056

Liddington-Whi tehorse 1 11260 660 +0 003

Whi tehorse-Liddington 2 11260 667 +0 010

Whi tehorse-Liddington 3 11260 702 +0 045

Liddington-Whi tehorse 4 11260 670 +0 013

Mean 11260 657

Standard Error of a Single Measurement 0 028 2 5ppm

Standard Error of the Mean 0 Oil 1 Oppm

Difference from Catenary

Length of 11260.677 0 020 1 8ppm

CAITHNESS BASE

Difference

Line Observer Di stance from mean

Warth Hill-Spital Hill 1 24828 706 +0 135

Spital Hi 11 -Warth Hill 2 24828 730 +0 159

Warth Hill-Spital Hill 1 24828 728 +0 157

Spital Hill-Warth Hill 2 24828 447 -0 124

Spital Hill-Warth Hill 2 24828 452 -0 119

Spital Hill-Warth Hill 5 24828 563 -0 008

Spital Hill-Warth Hill 4 24828 396 -0 175

Warth Hill-Spital Hill 2 24828 549 -0 022

Mean 24828 571

Standard Error of a Single Measurement 0 127 5 Ippm

Standard Error of the Mean 0 045 1 8ppm

Difference from Catenary

Length of 24828.633 0 062 2 5ppm

An EDM has been tested on the Ridgeway and Caithness bases

in the United Kingdom. The results obtained, and the com- parison with the surveyed distances, are given in the table

above. It should be noted that these figures have been

checked and confirmed by the British Ordinance Survey. All

distances are quoted in meters.

There is an excellent technology assessment "North American Datum" by the National

Academy of Sciences and the National Academy

of Engineering which discusses in detail why

there is a need for more accurate measurements and readjustments of the North American Datum. We have been in contact with representatives at NOAA and they expressed a desire to work with NBS concerning the problem

of calibration of EDM's. One of their con- cerns is that they have no simple way of ver- ifying the index of refraction and would like

NBS to set up a 4 - 5 Km (folded) baseline.

There exists some skepticism concerning

the accuracy of electronic distance measuring

systems under operational conditions. The

practical operating range along a highprecision geodetic traverse is 15 to 35 Km. Recent measurements made over a taped baseline in New Mexico are as follows:

Instrument No. 155L Instrument No. 441L

18,289.038 meters 18,289.035 meters

.041 .038

.035 .039

.048 .046

Mean:18,289.040 meters 18,289.040 meters

Taped length 18,289.046 meters

As to the economic impact of EDM's the

Coast and Geodetic Survey in the past few

38
years has completely converted to the use of EDM's for measuring distance. Tapes are only used for the calibration of these devices to the extent that the taoe oermits.

2.5.2.5 Integrated Circuit Industry

The semiconductor industry (SIC 3574) consists of establishments engaged in manufacturing semiconductor and solid state devices,

integrated microcircuits , and transistors,

etc. Values of shipments for the industry

will total more than $1,675 billion in 1973,

a 5% increase from 1972. (See Sector 16,

Electrical and Electronic, in the transactions matrix, table 2-9). A fundamental part of the IC industry is dimensional mask technology. A mask is a two dimensional array of patterns which must

satisfy certain criteria to be useful in the

manufacturing process of integrated circuits.

The photoengraving masks which give the geometry definition on the silicon wafer are made

through the use of high resolution photographic and photoreduction equipment, steo and re- peat camera, and precision drafting equipment. Using these techniques, a series of

masks are preoared which define the areas

for diffusion, contacts, etc. Each mask must

be precisely registered with all of the others

(there may be over 200), so that vyhen the

masks are superimposed, the registration between masks is kept within narrow tolerances.

One method used to produce a matrix of

circuit patterns is the steo-and-repeat pro- cess (fig. 2-27) which produces a two-dimensional array of images by a multiplicity of

exposures. Each exposure forms one image.

It is evident that the movement of the photographic plate between exposures must be done

with great accuracy and, in fact, it is usu- ally performed on an X-Y coordinate measuring machine. The lack of accuracy is unimportant as long as all masks are stepped on the same step-and-repeat system (lead screw

errors are repeatable and will position the

mask at the same place for each overlay).

But when a manufacturer is using many re- peaters then the problem of checking the out- put of these machines is complicated. One

such example of checking the lines of a standard plate is shown in figure 2-19 in section 2.3 where three different measuring

machines were used.

In modern microelectronics, complicated

structures with very small dimensions must

be fabricated on active-device materials.

This task has been traditionally accomplished

by photolithographic techniques but recently

small dedicated computers have been interfaced with scanning electron microscopes for

the purpose of generating, registering and

fabricating microelectronic devices and cirMETALIZATION MASK

OHMIC CONTACT MASK

E^flTTER DIFFUSION MASK

BASE DIFFUSION MASK

CHANNEL DIFFUSION MASK

USE OF PHOTO

LITHOGRAPHY IN IC INDUSTRY

REFERENCE OR SCALE LINES BROUGHT

INTO REGISTRATION MEASURING LIMES

ERROR Li..

^>v__ CHIP V

CHIP B STEP-AND-REPEAT

PROCESS IN IC INDUSTRY

LIGHT SOURCE

CHASE

PLATE

TRANSPORT

BED

UNIT IMAGE MOUNTED ON CHASE (lOX)

AUTOMATIC

LEAD SCREV/

CONTROL

Figure 2-27. Photolithography and step-andrepeat process in IC industry.

39
cuit patterns with submicron dimensions.

Registration accuracy of 0.1 micrometer over

a 950ym^ pattern field has been achieved [4]. A similar computer controlled electron

beam machine automated for fabrication of

microci rcuits has been developed. Considerable time and effort is being expended by

the various research laboratories to use the

electron beam as a machine tool to generate

more accurate lines, holes or shapes on a sub-micron level. At present these dimensions are approaching the optical limit of some of the most sophisticated measuring

machines. New methods must be developed to accurately measure these microelectronic devices so that the manufacturer can correct

errors before they become too costly.

2.5.2 6 Machine Tool Industry

The metalworking machinery and equipment

industry (SIC 3541, 3542, 3544, 3545, and

3548) constitutes by far the largest single

category user of length and dimensional measurements (see Sector 4, Machine Tool, in the

transactions matrix, table 2-9). Values of

shipments from these SIC codes industries

should total more than $5.03 billion in 1973

an average of a 12% increase over 1972.

Increased demand for high accuracy in

mass-produced machine parts has made it important for a manufacturer to have a working

knowledge of his tools. The determination of

the overall accuracy of the machine is important for:

(1) increasing productivity by producing

less scrap,

(2) reducing inspection time because more

parts will fall between the tolerance zones,

and

(3) maximizing the full potential accuracy

of the machine.

The machine tool and gage manufacturers

use either the base units of the national

measurement system and/or the base units of

the SI system of measurement. A plug or

ring gage or a measuring machine made by any

gage manufacturer may be used to measure a ball bearing manufactured in another part of

the country. For example, the bearing must

fit on an axle made in Detroit, Michigan,

which may have been measured by a gage made

in Massachusetts. It may also have to fit into a wheel made in Ohio and measured by a gage

or machine made in Providence, R.I. If the

machines that manufactured the ball bearing,

axle, and wheel were not closely tied into

the National Measurement System through gages

that were calibrated against the national

artifact at NBS, chaos would result. If the

gaging tools and measuring machines were not

calibrated, interchangeabil ity would be non- existent. Mass production as it is known today would quickly coma to a halt.

The tool and gage manufacturers must also

adhere closely to the national standards issued through ANSI since the majority of tools

and gages are purchased in accordance with an ANSI Standard. All ANSI Standards require

that the tool or gage be compatible with the

National Measurement System via a calibration

chain to the national artifact at NBS. The

transactions matrix shows that this category is a major user of NBS measurement

services

.

2.5.2.7 Marine Engineering

Establishments primarily engaged in the

building and repairing of all types of ships are classified by SIC code 3731 (see Sector

14, Other Transportation Equipment, in the

I/O Matrix, table 2-9). Dimensional measurements are important in all aspects of

ship building, for example, vibration and

noise in large reduction gears may be due to improper alignment or errors in roundness of

the shafts running in the bearings.

The value of work done in ship building

and repair yards on the U.S. mainland in 1973

is expected to total some $3.5 billion. This

improved market has spurred R&D toward new production techniques such as welding technologies, automation, and the applications of

laser technology for the alignment of hull

modul es

.

2.5.2.8 Metrology

Next to the metalworking industry, the

largest user of precise and accurate dimensional measurements exists within the metrological community. Dimensional metrology,

in a broad sense, means the science of all

measurements which are made by comparing the

dimensional ly measurable condition of an artifact to the unit of measurement (see

sections 5, 6, 7, and 8 in table 2-9.

As shown in table 2-9, DoD and Private

Standard Laboratories are very important

users of NBS measurement services since it

is the sole source for verifying their mea- surements against the national artifacts

and it is the only means by which they can

be sure that their measurement system is in

control

.

Metrology is invaluable to product design

in the manufacturing realm because measuring

techniques can be agreed upon to assure the

designer that the product will be measured

to meet functional requirements.

The metrological community has been

thought of as maintaining the highest standards for accuracy and precision. We can show the approximate need for accuracy by

figure 2-17 shown in section 2.3.

40
2.5.2.9 Petroleum Industry

One of the major users of accurate dimensional measurements is the petroleum industry. The industry uses threaded pipes in

drilling for oil all over the world and the

form and size of these threads must be con- trolled within tight limits. The threads

must be able to withstand extremely large

stresses and thus the need for accurate

thread form is great. The SIC code for the

establishments primarily engaged in manufacturing machinery and equipment for use in oil and gas fields is 3533 (see section 9,

Petroleum Industry, in the I/O Matrix, table 2-9).

Sample Uses : Figure 2-28 is a photograph of some of the standard gages developed by the

American Petroleum Institute (API) and used

world-wide by the oil industry. A typical

drill-stem assembly is shown in figure 2-29.

Considering the large number of threads in an average oil well the importance of accurate

dimensional measurements of the thread forms

is easy to appreciate.

Soecialized standards are seldom used in the Dimensional Technology Section at NBS

with the exceotion of the following API standards : (1) API STD 3 - API Specification of Cable

Drilling Rods

(2) API STD 5B - API Specification for

Threading, Gaging, and Thread Inspection of

Casing, Tubing, and Line Pipe Thread

(3) API STD 5L - API Specification for Line

Pipe

(4) API STD 7 - API Specification for Rotary

Drilling Equipment

(5) API STD IIB - API Soecification for

Sucker Rods.

All applicable API components are manufactured to these standards. Regional and ref- erence master gages' dimensions are measured

by NBS in accordance with the limits set forth in the applicable standard. If the

gage is within the acceptable limits, NBS

issues a certification of that fact to the owner or manufacturer. If the gage is not acceptable, NBS notifies the owner or manufacturer and returns it for rework or re- placement. NBS is the sole source, worldwide, for some of these measurements.

Economic Impact : The nations' demands for more energy has reached critical proportions

in recent years. To obtain oil you must

drill, of course, and to drill you need machinery and equipment. We can see the trend of

SIC 3533 by looking at Census Bureau figures.

Figure 2-28. Standard gages developed by

the American Petroleum Institute (API).

SIC

Code*

Value of Shipments

(mill ions of dol lars'

1958 1963 1969 1970 1971

3533 496.1 572.7 813.0 933.5 962.2

35531 222.0 217.2 322.8 372.6 376.5

35332 43.3 38.8 60.6 52.8 59.0

35333 175.4 261.4 308.4 355.1 360.6

35334 40.7 43.3 79.7 116.6 136.1

35330 14.6 11.9 41.5 36.4 30.0

*SIC codes are as follows:

3533 - Oil Field Machinery

35531 - Rotary Oil Equipment

35332 - Other Oil Drilling Machinery

35333 - Oil and Gas Production Machinery

35334 - Other Oil Field Machinery

35330 - Oil Field Machinery, not classified

Other data which are equally staggering

is the large number of threaded pipes which

must be produced to drill oil and gas wells.

From the API Petroleum Fact and Figures we

can obtain some interesting data on the

number of wells drilled in 1958.

Number of

Wells

14,227

3,385

12,987

876

1,439

Oil Producers

Gas Producers

Dry Holes

Strati graphic and

Core Tests

Service Wei 1

s

Total 32,914

By assuming the average length of pipe

tubing to be approximately 30 feet we begin

to get a feel for the immense need of conFootage

58,817,277

20,170,589

64,737,319

1,039,909

3,279,504

149,287,860

41
ROTARY BOX

CONNECTION L.H.

ROTARY PIN CONNECTION L.H. ROTARY BOX , CONNECTION L.H.

ROTARY PIN CONNECTION L.H. ROTARY BOX

CONNECTION L.H.

note:

ALL CONNECTIONS BETWEEN "lower

upset" of KELLY AND "bit" are R.H.

ROTARY PIN CONNECTION

ROTARY BOX

CONNECTION

ROTARY PIN CONNECTION

-SWIVEL

-SWIVEL STEM

-SWIVEL SUB

STD8A

ROTARY BOX

CONNECTION"

STD7

KELLY COCK

'(OPTIONAL) ROTARY PIN [ill. CONN ECT I0n"~~-~-^ J

Ik

-UPPER UPSET

ROTARY BOXCONNECTION

ROTARY PIN -r*7

CONNECTION 'XAj

ROTARY BOX

CONNECTION

-KELLY (SQUARE OR HEXAGON)

(SQUARE ILLUSTRATED)

-LOWER UPSET

KELLY COCK OR

-KELLY SAVER SUB

PROTECTOR

'RUBBER

(OPTIONAL)

ROTARY PIN CONNECTION

ROTARY BOX

CONNECTION

ROTARY BOX

CONNECTION

ROTARY PIN CONNECTION

TOOL JOINT 'BOX MEMBER

•DRILL PIPE

JOOL JOINT

'pIN MEMBER

CROSSOVER SUB

DRILL COLLAR

BIT SUB

BIT

Figure 2-29. Typical drill -stem assembly for oil industry (from API Spec 7)

trolling dimensions on these items. (Over

6.4 million threaded components.)

In 1969 the total production of crude oil , natural gas, and natural gasoline was approximately $4.75 billion. The petroleum industry is dimensional measurement-intensive in

a large subtle way.

2.5.2.10 Photogrammetry

Photogrammetry is the science and art of

obtaining surveys by means of photography.

The results of photogrammetry have second

and third-order impacts on geology, defense,

forestry, agriculture, and even archaeology

and medicine.

The industry is quite large so a complete

SIC code 3811341 was developed for photogrammetric equipment. It is included in Sector 3,

Precision Instruments, of the I/O Matrix, ta- ble 2-9. The value of shipments for this industry was $5.9 million in 1967.

With the advent of coordinate measuring

machines, photogrammetry has been advanced

Large grids (X-Y coordinates) are reproduced

on a glass and sent to NBS and other organizations for calibration and in turn are used

within industry 3811341. It has not been possible for us to evaluate the impact of these

devices upon that industry. Figure 2-18 in section 2.3 is from reliable sources. 2.5.2.11 Research and Development

The role of accurate and precise length

42
determination is varied in the field of R &

D. In many cases the use of the value for

the speed of light is the dominant factor in an experiment. Examples are: (a) ranging

from the earth to the moon by use of lasers

to obtain the distance to the retrorefl ectors

left on the surface, (b) study of strain in parts of the earth's crust, (c) study of movements across geological fault lines to develop

data bases for possible earthquake prediction,

and (d) determination of fundamental constants,

i.e. G, the gravitational constant, where the

distance between two points has to be known to

a high accuracy, and g, acceleration due to gravity, where a laser interferometer measures

the drop of a retrorefl ector.

2.5.2.12 Screw Thread Industry

The screw machine industry (SIC 345) has

been and is a major user of dimensional measurements. The form and size of threaded

products must be consistent if any degree of

interchangeabil ity is to be achieved in our modern society. SIC 3451 comprises establishments engaged in manufacturing automatic or hand screw machine products from rod, bar, or tube stock of metal, fiber, plastics, or other

materials. SIC 3452 comprises establishments

primarily engaged in manufacturing bolts,

nuts, screws, rivets, washers, and special industrial fasteners. This industry is included in Sector 4, Machine Tool, of the I/O Matrix, table 2-9.

Sample Uses : Dimensional control is an important aspect of the production of threaded

parts. The function of a thread is to transmit a force, serve as a fastening agent or control displacement, e.g. move the table of

a measuring machine. Thus we see that to ensure a consistent fit one must have dimensional control when the screw thread acts as

a fastener. When the screw thread serves as

a force transmitter dimensional control is

still very important because sufficient mechanical strength is necessary to prevent

failure and this strength is a function of

dimensional parameters of the screw. If it

is to be used to control displacement the

pitch and/or lead must be accurate.

A simple example of measurements in the screw thread industry is shown in figure 2-30

which shows current practices for the measurement of pitch diameters for thread gages. The

most notable work on screw thread standardization is NBS Handbook H28 Screw Thread Standards for Federal Services.

Economic : Recent figures for the fastener industry from the Census Bureau are shown at

right:

MEASURING CONTACT

Figure 2-30. Example of measurements in the

screw-thread industry.

Value of Shipments

(mi 1 1 ions of do! 1 ars)

SIC Code 1963 1969 1970 1971

3451* 588.9 1176.5 1088.0 987.6

3452* 1218.2 1823.2 1617.0 1625.1

345 Total 1807.1 2999.7 2705.0 2612.7

*SIC Code identification: 3451 Screw Machine

Products and 3452 Bolts, nuts, rivets, and

washers

2.5.2.13 Watch Industry

The watch-making industry is a major user

43
of dimensional measurements. When one con- siders the precision and craftsmanship which

go into a modern watch, one realizes that

tight tolerances must be held to produce a quality product. SIC code 3873 is for es- tablishments primarily engaged in manufacturing clocks and watches. It is included in

Sector 3, Precision Instruments, of the I/O

Matrix, table 2-9. In 1971 the value of

shipments of watches and clocks was $741 million.

This industry uses high grade micrometers

of various shapes and sizes, precision dial

indicators, toolmakers' measuring microscopes

and projectors. Plug gages are used in the

interest of speed and accuracy. The manufacturing interests are mainly in maintaining an "in-tol erance" condition rather than determining exactly where in that range the size falls,

2.5.2.14 General Public

The general public. Sector 20 of the I/O

Matrix, table 2-9, is a minor user of NBS

measurement services. The Dimensional Technology Section has an open door policy which

permits any qualified individual with a mea- surement problem to use our measuring equipment at no expense for a short period of

time (2-3 hours). Since many of these mea- surements are unique, NBS gains an insight

to some of the problems that the individual

artisan faces when developing a new idea or product

.

reporting the sales in the machine tool industry. This company sells products which

are not classified under SIC codes 3541 and

3542.

Table 2-12. Sales of a "typical" machine

tool manufacturer 1967-1974

oa 1 es aaj . Tor //o Year ba 1 es i nf1 a ti on

($ Million) ($ Million)

1967 32.9 32.9

1968 33.1 30.9

1969 32.0 28.0

1970 32.7 26.7

1971 28.7 21.9

1972 32.4 23.1

1973 39.8 26.5

1974 48.3 30.1

30.1

32.9 0.915

-8.5% growth

in 7 years

(Data from Value Line Investment Survey 12/74)

2.5.3 Summary Discussion of Major Users of

NBS Services'

The machine tool, oilfield machinery, chemical, and electronic computer industries are major users of NBS length measurement ser- vices. The accompanying table 2-6 shows the

sales trends in these industries during the

period 1967 to 1974. It is important that we talk about "real" growth, i.e. adjusted for

inflation. Therefore, the numbers have been

adjusted for a 7% annual inflation rate. When this is done, we see from the tables

that:

(1) The oilfield machinery and electronic

computer industries have had a real growth

during the period 1967 - 1974.

(2) The chemical industry has remained flat.

(3) The machine tool industry has had a negative growth. We also include the sales fig- ures for a "typical" machine tool company. It

is obvious that its sales performance is significantly different from the industry as a whole. This raises two points: (a) the obvious fact that the performance of individual

companies can depart significantly from the

average, and (b) it may be that the four digit SIC code is an overly fine tuned method of

44
3. IMPACT, STATUS, AND TRENDS OF

THE MEASUREMENT SYSTEM

3.1 Impact of Measurements

That the meter is defined as 1,650,763.73

vacuum wavelengths of light resulting from

the unperturbed atomic energy level transition 2pio-5p5 of the krypton isotope having

an atomic weight of 86, is of little concern

to the person on the street. To be able to relate to a user of length and dimensional

measurements is a task. The field is so vast

that only a sampling can be taken. To do

this we have assembled an array of numerous

branches of industry which are likely to be

concerned with accurate dimensional measurements. (See fig. 3-1.) This array contains

firms, industries, and technologies which

have large economic and social impacts upon

the economy.

3.1.1 Functional, Technological, and Scientific Applications

In the previous sections, many applications of length and related dimensional mea- surements have been discussed in context

with specific industrial application areas, specific instrumentation, and the like.

From these discussions, the following basic

categories of functional, technological or scientific aoolications and their impacts

can be derived:

Functional : Few people are interested in the spectral width or the coherence path

length of the iodine stabilized Helium-Neon

laser even though it is the de facto standard of length in the United States and is one hundred times more reproducible than the

krypton line. Most people are interested

only in the answer to the questions, "will

it work?" and "am I getting my money's

worth?" The largest volume of measurements

Airframes.

Watches

Scientific Instruments

Screw-Thread

Industry

Aircraft Equipment

Ball & Roller Bearings

IMPACT

LENGTH

Car Accessories

Domestic

Appliances

Electronic Equipment

Precision Metrological Apparatus

Gears

General Engineering

Pfiotogrammetryj

Geodetic Investigations

Petroleum Industry

Marine

Engineering

Integrated Circuit Industry

Machine Tools! Metrology

Figure 3-1. Impact of length.

45
falls in this functional category. An error of one percent in our length standard

could mean a loss (or gain) of literally

millions of dollars to the consumer. That

this has not happened nor is likely to happen appears to be due not to the high precision of our ultimate standard but rather

to the law enforcement arm of the office of

Weights and Measures and the integrity of

the American people. The National Measurement System must include a standard to which

all other measurements can be referenced but

to be most effective in this area, NBS should serve as its standardizing agency. It is of

greater importance that all manufacturers

make tile in standard sizes than whether or

not an individual tile is 0.0001 inch longer

or shorter than the nominal size. This can best be done on a voluntary basis but to serve as a catalyst and to protect unrepresented parties, the Bureau of Standards

should take an active role in these voluntary standardizing groups.

Technol ogies : The problems are different in

the high technology industries such as space

and aircraft. In these industries, measurements of component parts are often needed to

an accuracy comparable to that obtainable at the top measurement laboratories. The Bu- reau of Standards must maintain a technical

proficiency to meet these needs by being

able to make these measurements and by

disseminating information or participating

in cooperative programs that enable the

companies to make their own measurements

to the desired accuracy. There is a con- tinuing struggle to keep up with design

engineers who are now putting tolerances on gyroscope parts to a few microinches. The

Bureau must not only keep up with industry

but must anticipate future needs and be

prepared to provide even greater accuracy.

Scientific : Avogadro's constant and the speed

of light have recently been determined to an accuracy several times greater than the previous determinations. These advances were

due at least partly to improved length mea- surement technology. The inability to make

accurate length measurements has been the

limiting factor for some time in obtaining

more accurate values for several of the

fundamental constants. Like much basic re- search, the impact on the economy or GNP of

knowing a fundamental constant more accurately is often difficult to assess but the scientific community believes it to be a desirable and worthwhile goal and is also one of

the tasks of the Bureau of Standards as defined by Congress.

3.1.2 Economic Impacts - Costs and Benefits

For clarity, the industry size and the importance of measurements for the various industries was discussed earlier in sec. 2.5.2.

3.1.3 Social, Human, Person-on-the-Street

Imoacts

The many industrial applications of length

measurements obviously have major social significance. In addition, untold millions of

length measurements are made daily by the

various groups of people who have direct impact on our daily lives. Some of these groups

are listed below:

(1) Architects

(2) Construction Industry

(3) Craftsmen

(4) Lumbermen (gaging diameters of logs)

(5) Homeowners

(6) Housewives

(7) Doctors

(8) Police Department Accident Crews (each car carries a measuring tape to see how far

a car skidded, street widths, etc.)

(9) Printers

(10) Retail Stores

(11) Schools

(12) Surveyors

(13) Tank Gaging (tapes to gage the level of

liquids in oil and gas tanks)

(14) Utilities

(15) Auto and Truck Drivers.

Thousands of individuals make daily length

measurements without realizing that they are proving the viability of our National Measurement System. The housewife who measures

the length and width of a window for a pair

of curtains is not aware that the length of

her cloth measuring tape or wooden yardstick

is traceable to the national artifact at NBS,

however remotely, in the same manner as the

length measuring device used by the cloth

manufacturer or seamstress. When a typist

sets the margins on a typewriter, a length

standard is being set to which all other

typed lines are being compared. When a small

boy stands back to back with his father to determine how much he has grown, he is mea- suring his length against a standard - his

father.

If the organized National Measurement System were allowed to expire, the average person-on-the-street would in all probability

not realize it for a period of 10 to 15 years.

Sometime during that time he would find that some changes had occurred. For instance, the

automobile mileage between Washington, D.C. and New York City was no longer 240 miles

46
but was now measured by the auto odometer as 220 or 260 miles dependent upon the car he was driving - the difference being due to incorrect gear diameters in the odometer or to differences in tire diameters of "standard"

tires made by various manufacturers, etc. The automobile industry would probably

be the first to notice that close tolerance parts were not assembling properly

and that the gages used by the various

parts manufacturers throughout the country

were wearing at different rates. Since

there was no national artifact to calibrate these gages, serious disagreements

between supplier and user would result.

The big "loser" would be the consumer who

would receive inferior products at higher

cost. Although such inconsistencies would

be miniscule during the early years, over

a long period of time chaos would result

and industry would no doubt force the National Measurement System back into existence.

3.2 Status and Trends of the System

The status of the system has been discussed at length in other sections of this

report. In summary, the system is under control, in a state of dynamic equilibrium. No major deficiences exist, but many improvements are being made as new technologies are applied to let "old" measurements be made

with more precision, more accurately, more

rapidly, more inexpensively, and in more detail. The true status of the system is best

perceived by examining the current trends in the system. This is best seen by examining

the current trends in instrumentation in the

field.

We have developed the picture by looking

through some of the current trade journals

to get an overview of the new trends in instrumentation, gaging, and inspection which

appear in them.

Meahaniaal Engvneeving and Management - August 1972:

"A new philosophy seems to be emerging in

many oroduction areas - to eliminate human

intervention in making measurements and

interpreting the results of those measurements as much as possible.

"Electronics - Air gaging is still around

and is extremely useful but the current

trend, even in companies that have made

their reputations in air gaging, is to electronics. Because the price of electronics is coming down, it is now a matter of electricity versus compressed air

and electronics usually wins because of

its faster response time. Another reason for the trend is in in-process gaging.

electronics has the capability to provide

low magnification during heavy stock re- moval and high magnification in the finishing passes. This means that control

of size has increased exponentially.

"Lasers and minicomputers - As in the fields

of machine control, inspection and quality

control have felt the impact of the laser

and minicomputers. Examples are in sur- face plate calibration, roundness inspection, surface finish inspection, and

measuring machines. Coupling the laser

with a minicomputer has resulted in an entirely new concept of flaw detection in pipes and containers. It is designed to check not only surface finish, but is capable of detecting flaws such as scratches

and holes. The system was designed for

inspection of automotive cylinders and

data concerning the three related parameters - flaws, surface finish, and holes - are printed out in ten seconds.

"Transducing - The next big breakthrough in gaging is likely to be in the transducer

(gage head). Pratt and Whitney's Small

Tool Division has been developing an en- tirely new concept to the transducer.

"Metrication - According to most manufacturers,

the lethargy of Congress in passing the metric bill has had little or no effect on industry. Like it or not, che opinion is

we're heading for a metric America."

Iron Age, October 25, 1973:

"A single-axis electronic inspection instrument reduces by as much as 80% the time

required to accurately measure the height

of an engineered part.

"...the instrument supersedes devices such as vernier and micrometer-type height gages,

reference gage blocks, surface gages and

precision squares.

"...was designed for use on conventional sur- face tables. It incorporates an 8-digit

readout and offers repeatability to within 0.0002 inch."

American Machinist, October 15, 1973:

"Value engineering has been helped by metrology in this example where an air conditioner manufacturer that had previously

purchased his refrigerant pumps decided to build them in-house. The company did not

really know what was necessary to make a good pump but adopted the philosophy that

'the closer you measure prototype parts,

the better you can evaluate design criteria and manufacturing techniques and

the better you can plan for the critical

production jobs

"So what the air conditioning company did,

in effect, was to temporarily hire a 25-man toolmaking and gaging shop to pro47
duce prototype parts, which could never

be produced to the same tolerance (such as 50 millionths) on the production floor,

and then to go through a program of dimensional and functional analysis to select

critical dimensions and methods of pro-

. ducing and gaging them at a practical

level."

Bendix Technioal Journal, Summer/ Autumn 1972:

"In addition to increased productivity, com- puter-based automation is resulting in

high product quality, more efficient utilization of scarce natural resources....

"As the cost of... minicomputers continues

to drop, it will be possible to identify

an expanding set of cost-effective applications for automation in industry."

Laser Focus, January 1973:

"For industrial applications, sales of laser

instruments will increase (in 1973) 19.5%

to about $19.8 million... for such tasks

as interferometry, alignment and testing.

With tax incentives designed to encourage

modernization of machine tools in the

United States, industry officials expect

a dramatic increase from the meager 2%

that have precision numerical control - and therefore can justify interferometers."

Laser Focus, October 1973:

"As was the case two years ago, the principal military role of laser-related technology is to find a target by measuring

its distance from a weapon, illuminating

it, then guiding ordnance to it.

"These types of devices will perhaps spill over to the commercial sector. A system

to be delivered to Wright Patterson Air

Force Base for evaluating various types

of tracking methods will be able to do

ranging up to 20 miles."

Optical Spectra, May 1973:

"Con-.tructing, mining and mapping are only

three of the fields that have benefited

from the introduction of laser distancemeasuring equipment. It has been estimated that these applications currently

may account for the single biggest share

of the laser market (now a $216 million

i ndustry)

.

"The widespread conversion to EDM equipment

by the surveying profession is a direct

outgrowth of the demand for speed and

reliability in meeting escalated topographical and construction requirements...

"Laser units have attained a dominant position in the field because of high measuring ranges and high reference accuracies."

Hewlett-Packard Journal, August 1970:

"Increased demand for high accuracy in massproduced machined parts has forced the

machine tool industry to rely less on the

skill of the machinist and more on the

accuracy of the machine tool itself. This

has made it imperative that builders and users of machine tools continuously study

and improve their tools' operating characteristics, particularly positioning accuracy.

"...the development of the laser interferometer finally provided the machine tool

industry with a high accuracy length standard which could be used on machine tools ' of al 1 sizes . " \

Conversation with Engineer at Cincinnati

Milicron:

"Laser interferometers have revolutionized the

measurement of distances in excess of two

j feet. We use four laser interferometer sys- I tems on the shop floor for production and

testing in an automatic feedback loop."

' Cincinnati Milicron is a company engaged in the manufacture of grinders, forming machines,

lathes, and other machine tools (SIC 3541).

Its annual sales are $25 - 50 million.

Trends in the screw thread industry are of |, particular interest at this time. In 1970, | the members of the Industrial Fasteners In- stitute, a screw thread manufacturers' trade

association, initiated a "Study to Optimize

Metric Fasteners" because the US manufacturers want to export metric fasteners. The

present ISO Metric Fastener System was not

developed on sound engineering principles but was the result of many compromises from the

existing unified inch screw thread standards

and many national metric thread standards.

All of these standards have one common fault - proliferation of sizes causing excessive

stock inventories.

In May 1971, an ANSI Special Study Committee was organized and is known as the Optimum

Metric Fastener Study, OMFS. Its objectives

are technical improvements and the simplification of fasteners. The committee is working on a total system with dimensions and

properties stated in metric units. The goal

is the fewest possible sizes, series, types, i styles, and grades. The committee activities j cover product design, screw threads, form and

dimensions, material performance, and inspection and quality assurance.

NBS has participated in this study (Appendix H) through one of its staff, who is a member of this committee. At their request,

NBS gaged several hundred screws and nuts, of

various sizes, selected randomly from several screw manufacturers to determine if the thread

elements of these samples were within the limits specified by Handbook H28, Screw Thread

48
standards for Federal Services. The data

from this samDling will be used by the Committee to determine the thread tolerances for

the proposed Optimum Metric Screw Thread System.

4. SURVEY OF NBS SERVICES

4.1 The Past

In this section we will mention four past

developments in length measurements at NBS.

The first is the line scale interferometer

designed and built at NBS. Using lightwaves

from a laser source, the instrument measures

line standards directly in lengths ud to one meter and achieves an accuracy of about 1 oart

in 107 [5].

The second develooment was the computerizing of gage block calibration data in 1958 to 1959. Both mechanical and interferometric

measurements were programmed.

The third development was a program to improve the stability of gage block materials.

This was a cooperative program between the

Metrology and Metallurgy Divisions. Improved

metallurgical techniques made gage blocks more stable. As of 1960, three sets of gage

blocks from two materials were developed

which showed a dimensional stability of

2 X 10~7in ./in ./year over an observed period

of one year.

The fourth development was the NBS-Meggers

Standard Mercury 198 Lamp, created by

Dr. W. F. Meggers and initially distributed

in 1951. These lamps were capable of calibration to a precision of 1 part in 100 million, as opposed to the 1 part in 10 million

possible with the standard meter.

4.2 The Present - Scope of NBS Services

4.2.1 Description of NBS Services

The Dimensional Technology Section of the

NBS Institute of Basic Standards carries out

the Bureau's function in developing an adequate system of physical measurement for

length and related dimensional measurements

and in providing calibration services for

related industrial, military, and governmental standards. Its staff continually reviews

the advances in science and trends in technology and uses these to devise new measuring

devices and measurement techniques. A con- tinuing program is under way to extend the

range and improve the accuracies of all

length related measurements.

The principal emphasis is on the calibrations requiring such accuracy as can be

obtained only by direct comparison with NBS

standards. Test of measuring instruments to

determine comoliance with specifications or claims are made when the evaluation is critical in national scientific or technical operations and when suitable facilities are not available elsewhere. Referee tests are also

made in certain cases when clients are un- able to agree upon the method of measurement,

the results of tests, or the interoretation

of these results. The parties must agree in advance to accept the findings of NBS.

4.2.2 Users of NBS Services

The princioal users of NBS length calibration, consultant, and advisory services

are the Department of Defense Primary Standards Laboratories, gage manufacturers, com- mercial standards laboratories and various

industrial laboratories. These laboratories

send in their primary standards for calibration and then use these data to check their

working standards.

In the aporoDriate parts of section 4.3

there are several tables which contain a comprehensive listing of customers who re- quired some form of length calibration during the past few years.

4.2.3 Alternate Sources

There are many private standards laboratories that will calibrate industry standards

such as gage blocks, angle blocks, optical

flats, etc. for a fee. These laboratories

use standards that are routinely checked

against the national artifacts at NBS. Since

the calibration services at these laboratories are continuous and could be called miniproduction, the fees for their calibration

services are always less than those at NBS. Many of the large corporations maintain

their own standards laboratories but not

all of them will perform calibrations for

anyone outside the corporate structure. A partial listing of some of these industrial

laboratories is shown in Appendix F. The DoD also maintains its own standards

laboratories. The labs calibrate the primary and secondary standards used by the military. Again the standards used by the primary DoD labs are routinely checked against

the national artifacts at NBS.

4.2.4 Funding Sources for NBS Services

The fees charged for calibration of length

and related dimensional standards are "incremental," i.e. the number of hours actually

required to do the job including set-up time.

No other source of funds is available to pay

for this service. Research and miscellaneous brief consulting services (e.g. an- swering the mail and the telephone), are

49
financed from congressional appropriations.

4.2.5 Mechanism for Supplying Services

NBS Special Publication 250 "Calibration

and Test Services of the National Bureau of

Standards" lists all of the calibration ser- vices provided by NBS together with the cost

of each particular service. For a unique

item not listed in SP 250, a special fee is

mutually agreed upon after a discussion of

the method and accuracy of measurement is

determined between NBS and the user-usually

by telephone or personal contact.

4.3 Impact of NBS Services

The impact which length and dimensional

measurements have on various industries, technologies, and science has been discussed ore- viously. What we now need is some methodology to document a portion of the NBS user category.

The Dimensional Technology Section at NBS

has the responsibility for the NBS program in

length and its associated quantities. Pro- viding calibration services to the nation is

a basic function of this section; therefore,

it is assumed that this data and the customers

we do business with would be a worthwhile data

base. A comprehensive customer list for past

years within certain areas of dimensional

special izational was assembled. From this

an analysis was performed of each company

utilizing data contained in:

(1) Standard and Poor's Index of Corporations, and

(2) Moody's Handbook of Common Stocks.

When time permitted, the facilities of the

library of the Department of Commerce were

utilized.

It should be emphasized that this is only

a preliminary analysis of our customers. We have attempted in all cases to obtain at least a 50% evaluation of all NBS customers

to attain a reasonable sampling basis. Many

of the customers which we do business with

could not be found in standard reference texts

(S & P, Moody's, Dun & Bradstreet) so we have

begun other searches. One of the items which

we are considering is a comprehensive com- puterized analysis of our customers using many

SIC codes and other economic figures. The

purpose will allow us to simply add new

data every time a new company appears on our customer list. In many cases the NBS

customer profiles which we have already

made have been very informative.

4.3.1 Economic Impact of Major User Classes

For the purposes of our study, we have

sought to obtain trends in the interpretation

of our customers' Standard Industrial Classification (SIC) numbers insteac of attaching

significant weight to the individual numbers,

since many of our customers are conglomerates.

4.3.1.1 Gage Blocks - End Standards

Table 4-1 is a listing of private sector

customers who have sent gage block artifacts

to NBS for calibration for the previous four

years. (The DoD laboratories are not included

in this list.) A decision was made to include

several years in the base survey because some comoanies may send in items every other year

and thus only a year's sampling would not

have as much meaning. Figure 4-1 is a plot

that shows the companies with the highest

sales do not necessarily use NBS capabilities

to any greater extent than do other firms.

10 20 30 40 50 60 70 SO 90 GROSS OUTPUT DECREASING —

Figure 4-1. NBS customer profile - gage

blocks, 74% evaluation - total value of NBS

calibrations for companies 1970 to 1973 base

period

.

Figure 4-2 is an interesting diagram which

is a plot of the frequency of listing of SIC

codes (first two digits) for NBS customers.

By far, the largest user is Division D

- Manufacturing

.

From the Standard Industrial Classification

Manual, manufacturing is defined as: "...those establishments engaged in the mechanical or chemical transformation of inorganic or organic substances into new products,

and usually described as plants, factories,

or mills, which characteristically use powerdriven machines and materials handling equipment. Establishments engaged in assembling

component parts of manufactured products are also considered manufacturing if the new product is neither a structure nor other fixed

improvement .

50
Table 4-1. Gage block - NBS customer list - including company name, annual sales and standard industrial classification (SIC) code number.

Aerojet Liquid

Air Research

AVCO sales $687. 3 mil. SIC 3722,3662,4832,

4833,3522

Bell HelicoDter sales $400-500 mil. SIC 3728

Bendix sales 1.599 bil. SIC 3729,3714,3599,

3651

Boeing sales $3,040 bil SIC 3721,1925,3729

Browne and Sharoe Mfg. sales $52 mil.

SIC 3541,3494,3545

Bulova Watch sales S146.6 mil. SIC 3871,3651,

3679

Burroughs sales S932.7 mil SIC 3574,3573,

3579,3679,3955

C.E.J. Gage Co. (Subs Johannsen)

CPIC

Cincinnati Milacron Heald sales $25-50 mil

SIC 3541

Clark Equioment sales over $741 mil SIC 2541,

2542,3322,3325,3444

Continental Machines sales $14-16 mil

SIC 3545,3549,3561

Detronics sales Si mil SIC 3678

Dial Indicator

Oupont sales $3,879 bil. SIC 2892,2821,2818,

2819,2815

Eastman Kodak sales $2,975 bil. SIC 3861,2821,

2221,2899,2281

Fairchild Camera sales $193.1 mil. SIC 3861,

3611,3679,8911,3674

Farrand Controls SIC 3679

Federal Products SIC 3545

Ford Motor sales $16,433 bil. SIC 3711,3712,

3713

Freeland Gauge sales over $1 mil SIC 3829

General Dynamics sales SI. 812 bil SIC 3721,

3731,1925,3661,3679

General Electric sales $9,425 bil. SIC 3634,

3741,3621,3511,3651

General Instrument sales $275.9 mil. SIC 3674,

3673

General Motors sales $28,624 bil. SIC 3711,

3632,3585,3639,3741

Global Associates sales $40-50 mil. SIC 7399

E. Gottschalk sales $17-20 mil SIC 5311

Hughes Aircraft SIC 1925,3674,1941,3573,3611

IBM sales $8,274 bil SIC 3662,3573,3679,3572,

3579

IMI Metrology

Inspection Control

Intergraohic

Keuffel and Esser sales over $56 mil. SIC 3811

Litton Industries sales $2,446 bil SIC 3573,

3651,3579,3821,3679

Lockheed Aircraft sales $2,852 bil. SIC 3721,

3679,3731,4171,1925

MTI Corooration

B. L. Makepeace SIC 2752,3861,3952

David W. Mann (Div GCA Corp) sales $22.1 mil.

SIC 3811,3831

Marquardt Company

McDonnell Douglas sales $2,069 bil SIC 3721,

3679,1925

C. W. Menard

Metrolonics

Minnesota Mining & Mfg. sales 1.6 bil.

SIC 2295,2299,2641,2899,3042

National Astro Labs (Subs Comtel ) sales

$1 mil . SIC 7391

North American Rockwell sales $2.4 bil.

SIC 3566,3552,3732,3565,3811

Paper, Calmenson and Co. SIC 5091,3441,3542

Philco Ford sales S900 mi 1-1 bil. SIC 3651,

3632,3585,3631,3662

Pratt and Whitney (Subs. Colt Ind.) sales

707.3 mil . SIC 3541

Qual ity Tool Suopl ies

Rank Precision (Subs Rank Org. Ltd) sales

$142 mil SIC 7813,7011,3651,5099

Raytheon sales $1.2-1.3 mil SIC 3671,3673,

3679,3612,3693

Sanders Associates sales $100-200 mil.

SIC 3494,3662,3811,8911,3679

Size Control (Div AM Gage & Machine)

SIC 3545,3541,3729

Southern Gage

Soerry Rand sales $1,823 bil. SIC 3522,2531,

3569,3566,3621,2623

Standard Gage

L. S. Starrett sales $25-30 mil. SIC 3999,

3544,3545

TRW Systems SIC 8911

Taft-Peirce Mfg. SIC 3541,3544,3545,3599

Taper Micrometer (Div. IMC Elect.) sales

below $1 mil SIC 3545,3841

Teledyne sales $214 mil SIC 1382,3399,3499,

3674,3699,3722

Thiokol Chemical sales $215.7 mil SIC 2822,

3722,2821,3079,2818

Timken sales $250-400 mil. SIC 3562,3313,3532

Turman Construction

Ultralab

Union Carbide sales $3,037 bil. SIC 3624,

2819,2821,2833,3679

United Standard

Van Keuren sales $1-3 mil. SIC 3545

Veritek

Western Gear Sales $90-120 mil SIC 3391,

3729,3312,3555,3551

Westinqhouse sales $4.63 bil SIC 3613,3534,

3622,3631,3632

Note: The sales figures are from Standard & Poor's Corporation Register, 1973.

51
1 367 Electronic components and

accessories

2 354 Metalworking machinery and

equipment

3 356 General industrial machinery

and equipment

4 366 Communication equipment

C 0 E f

SIC MAJOR DIVISIONS

Figure 4-2. NBS customer profile - gage

blocks, 74% evaluation - frequency of listing of SIC codes.

In the United States the manufacturing

sector accounts for approximately 40% of the

gross national product (GNP). (1973 GNP was $1.27 trillion). Many manufacturing products

and services are produced to exacting shapes

and sizes, therefore accurate control of dimensions is necessary. Since many of these

products and services are exported and thus

enter into foreign countries, the need for

tight control becomes more apparent.

We may consider the other major groups

of figure 4-2, such as B and I, as "residuals", and these may have significance as second and even third-order impacts upon

the economy. A tentative observation for

major group "I" is that this group includes

establishments primarily engaged in rendering services to individuals and business es- tablishments, such as medical, legal, engineering, and other professional services;

educational institutions; and other miscellaneous services.

Figure 4-3 and figure 4-4 are more com- plete analyses of the NBS gage block customers in that the major divisions (D & H) of

figure 4-2 have been broken down into two and three-digit SIC codes.

We will analyze the most requent listing

of SIC codes from figures 4-3 and 4-4.

SIC

Frequency Code

36

35

28

37

Description

Electrical machinery, equipment, supplies

Machinery, except electrical

Chemicals & allied products

Transportation equipment and

Ordnance and accessories

>-o

aLU

CC

22 25 26 27 28 30 33 34 35 36 37 38 39 73 89 SIC CODE

Figure 4-3. NBS customer profile - gage

blocks, 74% evaluation - frequency of listing of SIC codes

.

J5J J55 3S6 357 358 359 361 362 363 365 366 367 369 372 373 SIC CODE

Figure 4-4. NBS customer profile - gage

blocks, 74% evaluation - frequency of listing of SIC codes.

52
VALUE OF SHIPMENTS (MILLIONS OF DOLLARS)

Figure 4-5. NBS customer profile - gage

blocks, 74% evaluation - number of companies

versus value of shipments.

Figure 4-5 shows that the value of individual company shipments for the customers of

NBS gage block calibration services was from

$.616 million to $14.5 billion. The total

cost of NBS calibrations for these companies

for the base years 1970-1973 was approximately

$256,535 or roughly $64,133 per year.

4.3.1.2 Tapes - Line Standards

The Customer Profile for the area of steel

tapes (linear line standards) is somewhat different. Table 4-2 is a comprehensive listing

of NBS customers for. the past four years, and

we immediately see that the category of users

is unique in that it includes almost all of

industry as well as individual surveyors.

Table 4-2. NBS customer list - tapes.

Industry

All ied Structure

American Standard

Arbaugh Engr. Supply

Arco Pipe Line

Ashland Oil

Babcock & Wilcox

Michael J. Baker

Baker-Wi bberl ey

Homer Banks, Jr. Beatty Machine

Bechtel Corp.

Bethlehem Steel

Brandis Sons

Burgess Behr

Robert M. Case

Canton City Blueorint

Chicago Bridge Inc. Chicago State Tape

Ciobra Spies

Colonial Hardware

County Engineering

John Davis

Davis Benoit

A. James DeBruin

Des Moines Steel

Eugene Dietzgen

Drago Supply Co.

J. J. Duenas

Henry Eagleton

R. P. Eastman

Eastman Kodak

Harold Eaton

R. H. Elrod Constr.

Evans Rule

Florida Level Trans

Fort Pitt Bridge

Friedl Harris

Gandolfo Kuhn

Garcia Hancock

General Iron Works

Georgia Blueprint

Great Blueprint

Green Engr . Aff i 1

Green-Massman

H. Greenstreet

I. M. Greenwood

David Grimes

H. T. Hall Co. Thomas J. Harris

Harman Construction

Hawaii Engineering

Hayevard & Paken

Peter B. Heidema

Highway Engineer

Hoffman Butler

Hubbill Roth

II 1 inoi s Regional

Land Surveyors

Int'l Nickel' Co. Kansas City Steel

Keson Industries

Keuffel & Esser

Peter Kiewet & Son

Krai Zeol Frei

Kratzent Jones

Lakeside Bridge

G. W'. Leach Co.

G. Lengemann Co. Lietz Co. Lockheed Shipping

Marke Lovejoy

Lowe Engineers

Luf kin

B. L. Makepeace

Charles Martin Insp.

Maxson Corp.

McGraw Edison

Measuregraoh Co. Charles W. Menard

Meridian Engineering

Midwest Surveyor

National Forge

National Surveying

Northern States

Nupla Coro.

Owen Steel Co. PGH Des Moines

Paper Calmenson

Patton Harris

E. Lionel Pavlo

Pharmer Engr.

Kenneth B. Pioer

Portland Precision

E. S. Preston, Assoc.

C. Marvin Raynor

Robbins Instrument

Justus Roe & Sons

Saltsman Constr.

D. L. Saundermann

E. W. Saybolt Co. Schneider Technology

Schofield Bros. Shea-Ball

Shell Oil Co. Shephers Inc. Andrew J. Shyka

Thorpe Smith

Southwest Tube

Spratt-Seaves

Standard Blueprint

Standard Oil (Ca.)

The Stanley Works

Stanislaus Co.

L. S. Starrett

G. A. Steadman

Stearnes-Roger

Steers-Kiewit

Sterling Maddox

Stone & Webster

Sun Pipe Line

Superintendence

Surveyors Instr. Dean R. Swift

Swindell -Drift

Mrs. J. W. Teacher

Union Carbide

U.S. Industries

Warren Knight

Westinghouse

Whaling Ciry

W. S. Wilson Corp.

Windsor Power

Zenith Surveying

Government

Agriculture Dept.

Air Force

Armv

Baltimore City

Baltimore County

Cal i fornia

Commerce Dept.

Defense Maooing

Georgia

Indiana

Interior Dept.

Iowa State Hwys

Los Angeles County

Maine

Monroe County

Navy Dept.

Nebraska

Pennsylvania

Redwood City

Texas Hwys.

Town of Trumbull

Transportation Dept.

West Virginia

Town of Winchester

Educational

Oregon Tech. Inst. Palomar College

53
Figure 4-6. NBS customer profile - tapes,

46% evaluation - NBS total calibrations for

system for years 70-73.

Figure 4-6 shows a breakdown into four

parts

:

(1) Federal, state, and local governments

and educational institutions

(2) Large companies (those whose net worth

is greater than $1 million)

(3) Medium size companies (those whose net

worth is less than $1 million)

(4) Small companies and individuals (this

is a general grouping of the companies not

listed in either S&P, Moody's, or Dun and

Bradstreet, plus indivuduals)

.

C 0 E F G SIC MAJOR DIVISIONS

Figure 4-7 shows again that the predominant user of NBS taoe calibration services is the manufacturing sector - Division D. But we now have customers from divisions (F) Wholesale and retail trade, (I) Government, (H) Ser- vices, (B) Mining, (E) Transportation, com- munication, electric, gas and sanitary ser- vices (SIC Code breakdown in tables 4-3, 4-4).

Table 4-3.

trial

.

Frequency

1

34

5

6

6

Table 4-4.

trial .

Users of tapes other than indusSIC

Code Description

34 Fabricated metal products,

except ordnance, machinery and transportation

35 Machinery, execpt electrical

36 Electrical machinery

59 Miscellaneous retail stores

38 Professional, scientific, & controlling instruments

33 Primary metal industries

50 Wholesale trade

Users of tapes other than indusSIC

Frequency Code

344

599

356

342

353

355

Figure 4-7. NBS customer profile - tapes,

46% evaluation - frequency of listing of

SIC codes.

Description

Fabricated structural metal

products

Retail stores

General industry machinery

and equipment

Cutlery, hand tools, and

general hardware

Construction, mining, and

materials handling ma- chinery and equipment

Duplicating, addressing,

blueprinting, photocopying, mailing, and stenographic services.

Figures 4-8 and 4-9 show that the value product shipments in 1972 for the customers of NBS

tape calibration services in the "medium-size"

company category was from $3.9 to $36.2 million. The value of product shipments for the

"large companies" who used NBS tape calibration services was from $4,625 to $13,805 billion for 1972 (fig. 4-10 and 4-11).

Other Line Standards : Tables 4-5 and 4-6 are

lists of NBS customers of the line standard

calibration service for the years 1970 - 1973.

Figure 4-12 and figure 4-13 show the results

of a similar analysis of the cutomer list and

again we see the manufacturing sector is a large user of NBS services. Another class of

54
22 23 24 25 27 28 29 31 33 34 35 36 37 38 39 46 49 50 59 73 76 89 SIC CODE

y

y. 1

SALES

Figure 4-8. NBS customer profile - tapes,

46% evaluation - frequency of listing of

SIC codes.

Figure 4-11. NBS customer profile - tapes

cross section of "large companies".

342 343 344 345 350 353 354 355 356 361 363 365 599 733 SIC CODE

Figure 4-9. NBS customer profile - tapes,

46% evaluation - frequency of listing of

SIC codes.

B C D E G H I SIC MAJOR GROUPS

Figure 4-12. NBS customer profile - line

standards, 46% evaluation - frequency of

1 isting of SIC codes

$0-i9O 190-300 S0O-3O0 SOO-tm OftK t miLuom NET WORTH THOUSANDS

SIC CODE

Hnn

Figure 4-10. NBS customer profile - tapes cross section of "medium-size" companies.

Figure 4-13. NBS customer profile - line

standards, 76% evaluation - frequency of

1 isting of SIC codes

55
user is category I or federal, state, and

local governments.

Table 4-5. NBS customer list for line standards

.

Industry

Bendix D. W. Mann Co. Bliss Portland Mark V Lab.

Brush Beryllium McDonnell Douglas

Consul Metok Ltd. Olympus Corp.

Dynamics Research Opto-Metric Tool

General Dynamics Kockwe M int i Hutchinson Ind. Texas Instr.

IBM Union Carbide

ITP Inc. Western Electric

Lockheed Georgia Westi nghouse

Government

Army New State Standards

111 inoi s

Educational

University of Cal ifornia

Table 4-6. Users of line standards other

than tapes

SIC

Frequency Code Description

1 36 Electrical machinery, equipment, & suppl ies

2 37 Transportation equipment

3 35 Machinery, except electrical

4 348 Ordnance and accessories

5 38 Professional, scientific, & controlling instruments

1 372 Aircraft and parts

2 366&367 Communication equipment,

electronic components

3 363 Household appl iances

4 371 Motor vehicles & motor ve- hide equipment.

<IMillion l-fO 10-100 100-500 500-IB i- 2 2-3 3-4 4-5 >5eillion SALES IN DOLLARS

Figure 4-14. NBS customer profile - line

standards, 76% evaluation - value of shipments .

56

Figure 4-14 is illustrative that the range

value of shipments of users of NBS line standard calibration services was from $2 million

to $9.5 billion in 1972.

4.3.1.3 American Petroleum Institute (API)

Gages

Table 4-7 is a comprehensive list of the

customers who have used NBS calibration ser- vices for API gages for the past ten years.

As in the previous cases, we utilized refer- ence S & P and Moody's to research each com- pany and break it down into its SIC component

codes. Figure 4-15 is a compilation of these

results and we see:

32 33 34 35 37 39 331 344 349 353 364 356 SIC CODE

Figure 4-15. NBS customer profile - API gages, 65% evaluation - frequency of listing

of SIC codes

.

SIC

Frequency Code Description

1 35 Machinery, except electrical

2 34 Fabricated metal products

3 33 Primary metal industries

1 353 Construction, mining, ma- chinery & equipment

2 344 Fabricated structural metal

products

3 331 Blast furnaces, steel workers, rolling and finishing mills

4 354 Metalworking machinery and

equi pment

It is interesting to note that SIC 3533

occurred the most frequently at this four

digit level (establishments engaged in manu- facturing machinery and equipment for use in oil and gas fields)

.

Table 4-7. NBS customer list - API Gages

Acme Fishing Tool Co. SIC 3533,3391

ARAI Iron Works Ltd. Japan

ARMCO Steel Corp sales $1 bil. SIC 3461,

3312,3533,3561 ,3323
Abegg & Reinhold Co. net worth over $1 mil.

SIC 3533

Alameda Gage Co. net worth $75-125,000

SIC 3545

Baash-Ross(Div Joy Mfg) sales $200-235 mil.

SIC 3536,3564,3561 ,3532

Baker Oil Tools Inc. sales $80-90 mil.

SIC 3533,1389

Bucyrus-Erie Co. sales $100-150 mil.

SIC 3531 ,3533

Brewster Co. sales $6-9 mil. SIC 3533,3323,

3553

Booz-Allen Applied Research Inc. SIC 7391

Creusot-Loire Div Material DeForage (France)

Canadian Reed Drilling Tools Ltd.

Coventry Gage and Tool Co. Ltd. (England)

Continental -Emsco Co. (Div Youngstown Sheet

& Tube, SIC 2177

Drilco (Div Smith Int'l) sales $75-80 mil.

SIC 3533,3449,3537

Dalmine Sp. A. (Italy)

Dover Corp. sales $162 mil. SIC 3599,3433,

3461 ,3533,3534

Dover Corp. (Canada)

Eastman Oil Well Survey Co. net worth over

$1 mil . SIC 1381

George E. Failing Co. (Div Azcon Corp) net worth over $1 mil. SIC 3533

Grant Oil Tool Co. sales $5 mil. SIC 3533,

5084

Gardner-Denver Co. SIC 3332,3345,3339

Greenfield Components Corp. sales 1-3 mil.

SIC 3999

Homco International Inc. Hughes Tool Co. SIC 3533,3721,3531,3532

Hunt Tool Co. sales $10 mil. SIC 3533,3443,

3731

Hydril Co. sales $15-35 mil. SIC 3533,3494,

3443

Herramientas de Acero S.A. De C.V. (Mexico)

Harbison-Fischer Mfg. Co. sales $10 mil.

SIC 3533,3561

Jones & Laughlin Steel Co. sales $950-1000

mil . SIC 3312,3491 ,3494,3317

Kuroda Precision Ind. Ltd (Japan)

Lone Star Tool Co. SIC 3533

Liberty Mfg. Co. of Texas net worth over $125,000 SIC 3533

H.E. Morris

Mannesmannroehrer-Werke A.G. (Germany)

National Standards Lab (Australia)

U.S. Steel Sales over $1 bil . SIC 3312,331 5,

3316,3441 ,3443

Pratt & Whitney (Subs Colt Ind.) SIC 3541,

3545

Pipe Machinery Co. sales $6-8 mil. SIC 3541,

3542

Reed Tool Co. Star Iron Works SIC 3591

Smith Tool Co. (Div Smith Int'l) sales 75-

80 mil . SIC 3533,3449,3537

Soc . P. AZ. James Massarenti (Italy)

Southern Gage Co. (Div. N.A. Woodworth) sales

$6-9 mil SIC 3545,3544

Spang and Co. SIC 3533,3297,3295,3341,3441

Steel Co. of Canada Ltd. sales $500-590 mil.

SIC 3312,3316,3441 ,3498,3481

Texas Iron Works net worth over $125,000

SIC 3533

Tsukamoto Seiki Co. Ltd (Japan)

Uie-Division Marep (France)

Usine Metal 1 urgique de Domine (France)

U.S. Ind. sales $1.2 bil. SIC 2311,2335,2337,

2341 ,2329

Alfred Wirth & Co. (West Germany)

Note: The sales figures are from Standard & Poor's Corporation Register, 1973. The net worth figures are from Dun & Bradstreet Ref- erence Book, Jan. 1967.

4.3.1.4 Angular Standards

The category of angular standards includes

angle blocks, oolygons, indexing tables, angle generators, optical wedges and prisms.

Table 4-8 is a listing of NBS customers ac- cording to uses of angle block calibrations,

angle generators, polygons, autocol 1 imators

,

and step mirrors and wedges. Figure 4-16 is

a SIC code analysis of the users of angle

block calibrations for industry. The most

frequent occurring is SIC 36 - Electrical ma- chinery, equipment and supplies.

Figure 4-17 is a similar SIC code analysis

for other angular standards - polygons, angle

generators, autocol 1 imators , indexing tables,

and step wedges, and mirrors. We again see that the most frequent are SIC 36 and 35.

20 28 30 32 34 35 36 37 38 26 35 36 37 38

SIC CODE SIC CODE

Figure 4-16 Figure 4-17

Figure 4-16. NBS customer profile - angle

blocks - 93% evaluation.

Figure 4-17. NBS customer profile - other

angular standards - 87% evaluation.

57
Table 4-8,

dards

.

NBS customer list - angular stanAngle Blocks - Industry

Aerojet Liquid

American Optical

AVCO

Engis Equipment Co GTE Labs

General Dynamics

General Electric

General Motors-AC

Goltschalk Co. Hercules Powder Co,

Hewlett Packard

Honeywel 1 , Inc

.

Hughes Aircraft

IBM

Kol Imorgen

LTV Lockheed Georgia

Lockheed Missile

McDonnell Douglas

Rockwell Intl.

Sperry Gyroscope

L.S. Starrett

Thiokol Chemical

Timken Roller Bearing

Union Carbide

Webber Gage

Angle Blocks - Government

Army Depot-Frankford

Army-Redstone

Dayton Air Force Depot

NASA/MSFC

Navy-ESL & WSL

Navy-Indianapol is

Navy-Newport, R.I. Navy-NAB Norfolk

Navy-North Island

Navy-Pensacola

Navy-Qual ity Assur- ance Angle Generators - Industry

General Dynamics Moore Special Tool

Angle Generators - Government

NASA Navy

Polygons - Industry

Ai research

Bendix

General Dynamics

General Motors

IBM

Kol Imorgen

Philco Ford

Rockwell Intl.

Surface Finishes, Inc Union Carbide

Polygons - Government

Newark Air Force

Autocoll imators - Industry

Bendix

Kaman Corp.

Rahn Granite

Sperry Rand

Texas Instruments

United Standards Lab.

Step Mirrors & Wedges - Industry '

Barnes Engineering Keuffel & Esser

Davidson Optronics Union Carbide

GTE

4.3.1.5 Related Dimensional Artifacts

This category of NBS customers includes

manufacturers and users of thread measuring

wires, rings and plugs, roundness standard;,

gears, calipers, optical flats, penetration

needles, balls, etc. Table 4-9 contains an exhaustive listing

of NBS customers in other dimensional areas

for the past four to six years. Figure 4-18

is the result of comoilation of the SIC analysis of companies who use the NBS optical

flat calibrations services. Again the largest category is within electrical machinery,

equipment and supplies. Figure 4-19 is an analysis of other users of NBS services for

other related dimensional standards such as those listed in table 4-9.

-.11I 22 26 28 30 36 36 37 38 SIC CODE

Figure 4-18

I _

12 35 36 37 38 48 73 SIC CODE

Figure 4-19

Figure 4-18. NBS customer profile - optical

flats, 64% evaluation.

Figure 4-19. NBS customer profile other

dimensional standards, 71% evaluation.

Table 4-9. NBS customer list

dimensional standards.

other

Optical Flats - Industry

A. C. Electronics

Acme Scientific

Advanced Optics

Aerojet General

Ai research

American Optical

Autonetics

AVCO Coro.

Bausch & Lomb

Barnes Engineering

Bendix

Boeing

Buhl Optical

Chrysl er Continental Machines

Cosmo Optics Inc. Crane Packing Co. Davidson Optronics Inc.

Dell Optics Co.

E & W Optical Co. Fairchild Ind.

Farrand Optical

J. W. Fecker Co. Fensor Optics

General Dynamics

General Electric

Goerz Optical

Hercules Powder Co. Hewlett Packard

Honeywel

1

Hudson Precision

Optics

Hughes Aircraft

ITE Circuit Breaker

Intl Optical

Kol Imorgen

Koppers Co. Korad Corp.

Legensohn Intl

.

Lockheed

Martin Marietta

McDonnell Douglas

McMann Optical

Mel par

Memorex

Mi nn . Mining & Mfg

.

Muffol itto Optical

Northrop

Optical Coating Lab

Optic-El ectronic

Orbitec Optical

Perkin Elmer

Philco Ford

Raytheon

58
Sandia

Scheer-Tumico

Space Optics

Special Optics

Speedlap

Sperry Rand

Starrett

Surface Finishes

Texas Instruments

Thiokol Chemical

Three B. Optical

Tinsley Labs

Union Carbide

Van Keuren

Webber Gage

Westinghouse

Willey Optical

Wollensak Optical Prod,

Zygo

National Astro Labs Trane

Optical Flats - Government

Army-Redstone

NASA

Mavy-ESL

Newark

Roundness Standards - Industry

Aerojet General

Ai research

Cincinnati Milicron

General Dynamics

General Motors

Hughes Aircraft

Natl Accelerator

Rank Organization Ltd,

Ringler-Dorin

Rockwell Intl.

Roundness Standards - Government

Army-Redstone

Gear Profiles Industry

Boeing

Fellows Gear

Landis Machines

Mich. TooUsub. EX-CELL-O)

Gear Profiles - Government

Army-Redstone

Calipers - Industry

Chrysler LTV Aerospace

Duluth Tinius Olson

Calipers - Government

State of Michigan

Penetration Needles Industry

AVCO

Chunking Machines

Comsat

General Dynamics

Penetration Needles

Humbolt .'-Ifr. Koehler Instruments

Precision Scientific

Van Keuren

Government

State of Missouri

Balls Industry

Aerojet General Mechanical Tech.

General Motors SKF Industries

Hughes Aircraft Sandia

Industrial Tectonics Union Carbide

Balls - Government

Navy

Thread Wires - Industry

Ai research General Dynamics

Bendix Hughes Aircraft

Boeing

Bulova Watch

Deltronic

LTV Aerospace

Lockheed

McDonnell Douglas

Pennoyer Dodge

Phil CO Ford

Sandia

Size Control

Tel edyne

Texas Instruments

Ultralab

Union Carbide

United Standards Lab

Van Keuren

Westinghouse

4.3.2 I echnol ogi cal Impact of NBS Services

Detailed information on this aspect will

be found in section 4.4, but in general there

appears to be no great effect on technology

because of or due to NBS services. Industry

cannot use and does not require the accuracies

to which NBS calibrates their standards. The

greatest service NBS could supply to improve

the technology of industry would be to provide more "cook books" or "how we do it" manuals for use by technicians.

4.3.3 Pay-off from Changes in NBS Services

With the acquisition of our large 3-axis

measuring machine, we have been able to provide calibrations of large ball plates,

24 X 48 inches, for industry. By adapting

a mini -computer to this machine, we have re- duced calibration time for 12 or 18 inch step

gages by more than 50% with a corresponding

decrease in cost. By using laser interferometers as the measuring device instead of the

machine lead screw we have increased the re- ported accuracy of our calibrations more than

50%. We are continually adapting more of our routine calibration work to use this computeraided measuring machine. In the near future

we exoect that most of our API gage calibrations will be routinely made on this computeraided machine.

4.4 Evaluation of NBS Program

One of the major advantages of this study

of the National Measurement System for Length

and Related Dimensional Measurements is the

tremendous number of formal and informal con- tacts which we have established with other

governmental agencies and the industrial sector. The major reason for these contact was

not specifically to test our NBS model but to develop better ties with industry so that we might understand the "health" of the system,

i.e., how well are dimensional measurements

being made throughout the country? This is

a difficult question to answer because as we have already pointed out, one must continually

monitor the measuring process before one can

be sure a measurement is being made.

Contacts throughout the industry were made

by the following methods:

59
(1) An industry canvas and also telephone

interviews with selected people,

(2) contacts with technical societies and/or

publications in the area of interest,

(3) "Outreach" program,

(4) literature search for pertinent "roundrobins" or audit packages.

4.4.1 Response to Questions in Industry

Canvass

Question : If you use the services of NBS,

please state in what way. Why do you use these services? Do you find these services

adequate or inadequate? Plese tell how you

feel these might be improved.

"NBS calibrates our grandmaster gage blocks

Which provide a double check on our own measurements and the NBS traceback neces- sary to conform to MIL and Federal Specifications. Service is quite adequate for

our needs. We would like to see a precision of 0.1 millionth in measurements, but

realize some limitations are in the geometry of the items being measured."

"NBS services provide us with traceable master standards for the calibration laboratories which insures a high confidence

level of inter changeability of manufactured parts. NBS services have been adequate but could be improved by a reduction

in turn-around time for calibrating standards."

"Use NBS for calibration to achieve traceability. Service adequate for our needs."

"Calibration of primary line scales. None of our customers know how to use you and might

not anyway because of time consideration."

"Certifying and measuring steel tape - for

100(?) years. Service is slow."

"Masters calibration (blocks and wires). Also

some use of NBS standards and literature.

Service on blocks has been excellent. Wire

calibration too undependable delivery wise,

and too expensive."

"Gage block calibration for traceabi 1 ity

.

Assurance and forced by government regulations. Adequate but expensive."

Question : Do you feel that NBS gives

enough assistance to various manufacturers

around the country? Please explain how you

think the situation might be improved?

"No. We believe this situation could be improved if NBS would become more involved

in recommending specific measuring systems and techniques which would result in

a finished product of a specified accuracy

level ." "With new gage makers association, perhaps

combined meetings in various regions semiannually (or oftener) would be worthwhile."

"Most people do not know or understand the

NBS role. Government regulations, as they

filter down through channels, have a way

of changing from original intent through

human bias and become quite restrictive

and burdensome to many. A good example of

this is a change of a government inspector

in your plant. The regulation did not

change but the interpretation did. Cost

consciousness seems to be lost in their

dealings. Documentation rather than actual

practice has more importance, regardless

of cost of this documentation in relationship to its use."

Question : Are there any problems in your

manufacturing processes where an improvement

in the accuracy or precision or method of dimensional measurement might help raise producti vity?

"Measurement processes are not now a deterrent to productivity."

"Generally, surveys have shown that adequate

accuracy and precision has been available

to meet our needs .

"No. At present there are some areas we could improve productivity by updating

the equipment presently available but the

economics don't justify equipment cost."

"...lead accuracy of screws. NBS could most

likely help in the theoretical areas be- cause you are staffed with brilliant men,

but the actual solutions are practical res- olutions with a resultant economical piece

of equipment by industry. Accurate and

precise non-contacting type of equipment

that can be mounted on the manufacturing

machine would be a Utopia!"

Question : If some of your personnel at- tended the NBS Dimensional Accuracy in Manufacturing Conference in 1972, what were their

impressions? How could the conference have

been improved?

"did not attend."

"...comments that the conference was educational but was conducted above his working

level . The conference should be repeated

regularly and either have professional

metrologists attend or lower the level of

the material presented."

"Varied. Any conference on your discipline

is good. Especially interesting is the

interface through questions after the

lectures. One problem is that the mun- dane important items in every day life

are not exotic enough to talk about. Many

are involved with problems in the areas of'

.000050, and they hear laboratory talk of

parts per billion. Some subjects are con60
fined to specialized fields that do not

have universal appeal. Feeling of some was that the subjects were of more interest to NBS in a laboratory field than to the attendees in the practical application

of laboratory findings."

Question : Do you feel that if you had to "prove" the accuracy of your measurements in

a court of law, you would have sufficient

evidence to convince the jury?

"We have never had a court test. If necessary, we see no difficulty in convincing

a jury because of our traceback and agreement with NBS measurements."

"We believe our measurement accuracy is provable since we maintain written records of

the calibration of measuring devices and are able to prove traceability to NBS.

Such proof is important to any manufacturer. " "Bureau masters. Traceability and current

calibration reports on working masters,

etc. Yes, we believe we could 'prove' our case."

"This would be very difficult. Would depend

upon personalities. How could you avoid

the twisting by a lawyer that the measurement has inaccuracies caused by the instrument, the operator, the product and the

process? Your terminology alone of precision and accuracy and statistical means would be like Greek to the jury. The type

of evidence would have to be plausible,

easily understandable explanations. It would be difficult to prove that this particular article involved in fact did get

measured under a sampling system, and even though it did not, that you have assurance

that it, in fact, is a good article.

"In the present situation of our marketplace,

we see no need for this proof."

Question : What type of training - seminars and/or publications would you like to see emanate from NBS in these areas of interest?

"Practical training in the use of general

type of dimensional measuring devices

with an emphasis on the expected accuracy

when using a particular device. Example:

Can you expect a measurement to be accu- rate to 0.0001 inch just because the readability of the micrometer is 0.0001 inch?

Material should be personal and published

in trade and management magazines."

"...capable of training personnel ourselves

to meet present needs."

"How to make accurate optical length measurements. What to do - not simply what to avoid doing! Linear and angular encoder

industry. Quality Assurance and Engineering."

"Available services to industry and civil

engineer. With the advent of increased

usage of metric, engineering associations

should be advised of your capabilities to service metric graduated tapes as well as English. One factor that has reduced the

Bureau's capability image is the continued

cry for additional operating funds. In- dustry will add additional staff and equipment because of fear that (the) Bureau will

not have enough capable operating personnel 1 and equipment."

"Let 3:j^Z-lty Ma-cagame-nt magazine and ASQC

handle training (i.e., seminars at various colleges around country, etc.). Publish with society and giV magazine for best

distribution.

"Accomol ishment of reliable measurements in less time under practical conditions rather laboratory conditions. Most supervision gets quite a few magazines across their desk. This would be the best vehicle.

Feel quite certain that Quality Ma-nageme-nt

& Engineeying would welcome Bureau articles. This seems to be quite universally

read by those involved with measurements."

Question : What is your current concept of

NBS? How do you visualize NBS as you think

it should be?

"Our current concept is generally favorable

with some qualifications regarding the

fact that the cost of NBS measurements now often exceeds the manufacturing cost of the

item to be measured. Our opinion on what

NBS should be is that its activities should

encomoass: Cl) measurement authority - Ca) perform calibrations of primary standards only for gage block manufacturers,

qualified commercial calibrating laboratories and government agency calibration

facilities. Other than primary standards

calibrations could be done by manufacturers

or commercial labs, thus freeing NBS of

expended costs in handling measurements

that do not take full advantage of their

abilities, (b) NBS should establish accuracy and precision standards, as well as methods of measurement for the calibration

of primary standards and the instrumentation involved in such measurements. (2) Ar- bitration - In instances of stalemates in

agreement on measurements between contractors and suppliers, NBS should be the ar- bitrator. (3) Research and Development - To continue to advance the state-of-theart in instrumentation, methods of mea- surement and standards without the neces- sity of such programs being financially

subsidized by private industry."

61
"We believe that NBS is responsible for providing the basic standards for the national measurement system. NBS should provide

leadership and direction in national mea- surement problems such as metrication."

"Repository of standards. Far-out research

projects. Promulgation of H-28 (and other

reference material). Above are all neces- sary functions. Perhaps more practical

application of theoretical to industries'

needs and dissemination of those ideas into better media .

"Varied, from no concept through a government

agency that is the final answer of what is

standard to a group of dedicated, intelligent scientists who are working in laboratory conditions on very interesting subjects in basic research. They are splitting millionths while we are chasing tenths

"We have standards organizations on top of

standards organizations, and government

agencies, establishing standards, and many

times conflicting standards, on every as- pect of our environment. We need a clearinghouse for these that is working closely

with and a part of international organizations such as the ISO.

"The National Bureau of Standards should be a clearinghouse for these standards as well

as physical standards."

4.4.2 Contacts with Technical and Trade

Societies and Journals

We felt it might be desirable to contact

pertinent journals and/or technical societies

in the area of dimensional measurements and

establish a dialogue with certain individuals

within these organizations.

The Executive Editor of Manufacturing Engineering and Management was contacted and

was extremely interested that we were interested in the problems of industry. "The image of NBS... could be enhanced by a concerted public relations effort. It needs to com- municate better with the manufacturing com- munity as to its ability, and desire to be- come more involved in the real world - beyond

certifying the calibration of gage blocks.

It is somewhat paradoxical to have to sell

what you are prepared to give away, but I believe this to be critical to your effort."

The Associate Editor of American Machinist

attended the Dimensional Conference in 1972,

and we have had several telephone conversations with him since that time. He is, of

course, close to the machine tool industry

because of the nature of his magazine. His

idea of more meaningful dialogue between NBS

and industry comes under the heading of more

and better organized symposia. In fact, the

services of the McGraw-Hill Manufacturing Re- search Institute were offered in the area of

questionnaires and seminar organization. He also commented in a recent letter that "our publisher (McGraw-Hill)... mentioned that we should improve our contact with NBS."

Another publication Machine Design was con- tacted for an analysis of their contacts with

industry and the feelings of those contacts

toward NBS. Their Technical Editor responded

again that industry needs more exposure to NBS - its capabilities and resources.

In all of our encounters with the area of

trade journals, etc. the editors have been

extremely interested and willing to help in

the dissemination of any material which we might develop.

Several individuals within the Society of

Manufacturing Engineers (SME) were contacted

and asked to explore with their associates

the idea of our developing better ties in industry. Two volunteered to send out queries to various members with the intention of

gaging feelings toward NBS and seeing if any

measurement-intensive problems do exist in

the areas under SME.

It is interesting to note that as a re- sult of these queries, we received a reply

from a manufacturer who was having extreme

problems in areas of nondestructive testing of jet engine components. The problem

revolved around detection of cracks, 50

microinches wide with a depth of four

times the width, in a repeatable manner.

A telephone conference was established and

as more information unfolded, we were able

to steer our contact to the appropriate man

at NBS. Thus, from an inquiry made in one

field, we were able to help another area in

a measurement problem of vital importance

for consumers who ride in airplanes.

The Director of the Technical Activities

Division of SME was in contact with us re- cently and invited us to become familiar

with the Inspection and Quality Control Division of SME. The Division is composed of the

QC and Management subdivision. Inspection and

Metrology subdivision, and Surface Integrity

subdivision. The Chairman of the Division

was contacted recently and informed of our studies. The Division is now in the process

of being reorganized but we were invited to participate in the Division after it is re- organized. SME represents thousands of com- panies and this looks like a good opportunity

for NBS to strengthen its contacts with

industry.

The Executive Director of the American Society for Quality Control (ASQC) was also

contacted. The ASQC is a technical society

of more than 20,000 members engaged in the

management, engineering, and scientific as- pects of quality and reliability. There ex- ists within the ASQC a metrology division and

a chairman of a gage lab corporation was

62
contacted to discuss any potential dimensional measurement problems. He had some definite

ideas on how NBS could interact better with

industry through practical seminars and workshops on topics such as the usage and capabilities of laser interferometers and various

calibration procedures.

Other organizations we have contacted and are developing interactions with are: The

llatio'tiol Machine Tool Builders Association^

American Ordnance Association, American Congress of Surveying and Mapping, MacCalester

College in St . Paul

In the early 1960's, the Aerospace Industries Association, representing 80 of the

nation's most advanced firms, surveyed industry concerning their measurement needs. To see if there were currently any measurementintensive needs, we contacted the Washington

headquarters of the AIA for information. We were informed that a standing committee was established and learned of the Chairman of

the Quality Assurance Committee. We con- tacted him recently and learned he had been

chairman for over 20 years. He was aware of

many problems which were dimensional measure- ment-intensive back in the early 1960's but

lately he has not received any calls con- cerning present or future needs.

4.4.3 "Outreach" Program

In the past few years, the management of

the Dimensional Technology Section at NBS

started to "reach out" to the outside world

by sending personnel on fact-finding missions

to various companies around the country.

Anytime someone visited a part of the country

on either personal or business reasons, the area is usually searched to find any interesting visits that might be made. Well over

50 personal visits have been made by NBS Dimensional Technology personnel or reciprocal

visits by industry to NBS since early 1972.

A brief chronology will give the reader an idea of the scope of our contacts. In many

cases no earth-shattering needs were un- covered, but lasting contacts have been establ ished.

(1) In 1972, a few members of the Dimensional Technology Section attended the American Ordnance Association meeting for the

purpose of becoming better acquainted with

members of that organization. Benefits derived from the meeting were familiarity with

some of the measurement problems encountered

in the ordnance areas and getting to know

various individuals.

(2) In the Fall of 1972 we attended the In- ternational Machine Tool Show in Chicago

sponsored by the International Machine Tool

Builder's Association. 1972 was the first

year for the show to go international in scope and over 70,000 people attended. This

provided an excellent opportunity to see new equipment and to talk with various individuals over the possibility of whether better

dimensional measurements might help raise

productivity. The consensus of opinion was

that the honest tenth (0.0001 inch) was the

most diligently sought for accuracy in industry. It was also borne out that the manufacturer would like to be able to produce and

inspect the part on-the-fly as well as obtain

some information concerning the operational

characteristics of his machine. This particular comment has been repeated many times to

us by people in the industrial sector.

(3) At the same time while we were in Chicago, a commercial lab was visited. There are

several independent laboratories scattered

around the country which offer industrial

firms a chance to remain competitive by providing them with the opportunities to keep

quality in their manufactured products without a major investment in testing and calibrating equipment. The midwest Gage Laboratory which is part of the American Gage & Machine Company was visited. The Director

was concerned over the high cost of many of

NBS services, but felt the cost was justified

considering the quality of the service and

employees needed at the Bureau. His main

suggestion was that NBS keep up dialogue with

industry through meaningful publications,

either through trade journals or NBS documents which will reach the real user.

(4) In June 1972, the US Army Metrology and

Calibration Center at Redstone Arsenal, and

the Quality and Reliability Assurance Laboratory of NASA's Marshall Space Flight Center, were visited. The John M. Core Laboratory

at Redstone occupies 39,000 square feet with

the physical standards lab occupying approximately half that total. The Chief of the

Electrical Standards Lab presented a general

overview of the facility and had no com- plaints over the availability of services of

NBS. (He was concerned over his inability to obtain a VOR azimuth angle standard from NBS.)

A Group Leader of the Temperature and Vibration Section felt that more should be done

with keeping people "up-to-date" on new procedures and measuring techniques. The Group

Leader of Length, Angle, and Mass would like

to have seen publications on surface finish,

a heat transfer study of a typical metrology

room to prove to management the "need for the

stringent precautions," results of our evaluation of a laser interferometer system, and

involute profiles. A technician in the group was pleased with the performance of NBS but

63
had reservations concerning the relatively

new method of calibrating long gage blocks

and wanted to see reports covering the "buildup" wringing uncertainty for long blocks and

the uncertainty due to elastic deformation

occurring during the measurement of artifacts.

The major impression received was that these

people were overwhelmed that we were aware of

their existence and were willing to help.

They were reluctant to admit their mundane

problems until prodded gently. The consenses

of opinion here was the need for more publications emanating from NBS and the need for

continuing dialogue.

(5) North American Rockwell - Autonetics

Metrology Laboratory, Anaheim, California.

It has recently been designated as one of the

official State Laboratories of the California

Calibration Service and is responsible for

the calibration of all industry standards

within their assigned area of the state. It maintains standards which are calibrated and

certified by NBS. It calibrates and certifies those standards and instruments which

are used by the laboratories of Autonetics

divisions in the calibration of test and measuring instruments. Autonetics is a major

supplier of inertia! guidance systems for

the DoD and NASA. The accuracy requirements

for the rotor in their gyro, 20 microinches

on the diameter and 5 microinches on roundness, is probably the tightest in industry

for a production item. A supervisor of the Metrology and Calibration Laboratory says that there is no need for greater accuracy in their measuring

equipment or standards at the present time.

Fabrication techniques and technology must

improve before any significant change in

measuring equipment or techniques is required.

(6) Navy Standards Laboratory, Pomona, California, provides calibration and special test/

evaluation services for other Navy Standards

and Calibration Laboratories, other government activities. Navy contractors, and other

DoD contractors within the Eleventh Naval

District. Calibration services are also provided to participants of the NAVELEX and

NAVSHIP Calibration Programs in the Pacific

area as directed. In addition, calibration

and special test services are provided to the

participants of the Fleet Ballistic Missile

Weapons System Calibration Program within the

Continental United States as directed by the

Strategic System Project Office. These functions consist of direct and indirect fleet

support to insure traceability to standards

maintained by NBS and/or the Navy.

This facility is a secondary laboratory

whose prime function is the support, calibration and test of the metrology equipment used

in the US ship yards and aboard the various

naval vessels. One of its major activities

is the design and fabrication of special

gages for use with the Polaris and Poseidon

missile systems. These gages are used during

the assembly and installation of these missile systems aboard the ship.

The director of the laboratory states that

they have no particular problems and that the

services provided by NBS are quite satisfactory for their present needs and those of the

foreseeable future. He did complain of the

extremely long "turn around" time for calibrations at NBS several years ago which

forced them to send their standards to the

Navy Primary Standards Laboratories, ESL, in

Washington, D.C., or WSL in San Diego, California, for calibration and traceability to

NBS. He requested that they be made aware

of any new process or technique developed at NBS that may help them. He welcomed the idea

that NBS was trying to assess the requirements of the various agencies and industry

and the willingness of NBS to improve its

capability where necessary.

(7) Moore Special Tool Company of Bridgeport,

Conn., sells approximately 12 measuring ma- chines per year, total cost approximately

$500,000. These machines have greater accuracy than the coordinate measuring machines,

consequently, they are primarily used in the

various research laboratories rather than the

metrology laboratories of industry. The

chief engineer of Moore Special Tool said

that they are continually upgrading the accuracy of the lead screws that are used in their measuring machines and jig grinders.

The accuracy of the lead screws used in the

jig grinders and jig borers is guaranteed to be within 90 microinches per axis. This is

a factor of 3 better than the measuring capability of most coordinate measuring machines.

The Moore measuring machine is capable of

measuring to the required accuracy, but it is

relatively expensive, rather time-consuming

to operate and must be in a controlled en- vironment to obtain this type of accuracy

and precision. It is doubtful if better ac- curacy can be obtained by using a precision

lead screw without some type of automatic

correction feature to compensate for pitch

and lead errors. Accurate line scales. Moire scales and

linear inductosyns are presently being used

and appear to be the best choice for greater

accuracy in measuring machines as well as machine tools. At present Moore Special

Tool has no plans to incorporate any of

these devices in their machines.

(8) In recent months we have visited or have been visited by representatives of the

64
fol lowing:

Agriculture, Department of - Maryland

State Office of Weights & Measures, discussing needs of state labs for dimensional

and length measurements.

Army Metrology and Calibration Center

Autonetics

BAI Corporation

Battelle Pacific Northwest Lab

Bausch & Lomb Inc. Bendix Corporation

Canada Wire & Cable Co. Commerce, Department of, Scientific & Technical Instrumentation, discussing trends in new devices and instrumentation.

Deltronics Gage Corporation - discussing

measurement problems in general with particular emphasis on thread wires and plug gages.

Eastman Kodak Co. General Dynamics (Convair) discussing mea- surement problems in general.

IBM Corporation (San Jose)

K & E - discussing the future of Electronic Distance Measuring Devices and the possibility of cheaper units replacing many steel

tapes on the market now. Moore Special Tool Company

National Machine Tool Builder Association

National Bureau of Standards - Office of

Weights & Measures, discussing needs of state

labs for dimensional and length measurements.

Navy - ESL, becoming familiar with the

calibration programs and problems of the Navy.

Navy Standards Lab (Pomona)

NOAA, National Geodetic Survey, discussing

ranging problems which NOAA is currently facing and will be facing in the future.

Sandia (Physical Standards Lab) discussing

implementation of Measurement Assurance Program (MAP) processes to thread wires and

other artifacts.

Union Carbide Corporation.

4.4.4 Exhibit in the International Machine

Tool Show 1974

In view of improving ties with industry

and publicizing the capabilities to some extent, we had for the first time, a manned ex- hibit at the International Machine Tool Show

(ITMS) in Chicago, September 1974. The ITMS

is the largest industrial show held in the

USA. There were over 300 machine tools in

operation; computer and control equipment;

inspection, gaging, and testing equipment;

material handling equipment, etc.; equipment from 30 nations and 78,151 registered

visitors

NBS had an attractive display manned by

qualified personnel experienced in the field

of dimensional measurements, surface roughness measurements, and optical instrumentation, since these are the areas of most interest to the machine tool industry.

An estimate of 4000 people stopped at the

booth to pick up various NBS publications.

Four hundred and sixty-one stopped to talk, some about their particular problems and

others to learn more about NBS activities.

These 451 people requested a total of 1300

copies of the Dimensional Technology and

Optics and Micrometrology reports. The ma- jority of these reports are "how we do it."

They describe in detail how we measure or calibrate industry standards. Because of

the many requests we have compiled a list

of all these reports which are available to those who need or request them.

The response to the NBS exhibit was so satisfactory that we plan a repeat perform- ance at the next ITMS in September 1976.

4.4.5 High Efficiency Methods for Dimensional Calibrations

A two-day seminar on High Efficiency Methods for Dimensional Calibrations was held in

June 1974. Approximately 20 people from industrial and military standard laboratories

attended. Knowledgeable personnel from the

Dimensional Technology and other sections

described how the efficiency (cost/unit calibration at fixed accuracy) of dimensional

calibrations could be improved by appropriate use of experimental design and time

shared computer data processing. The practical application of these methods, as applied to gage blocks, thread wires, and twodimensional ball check-out plates for coor- dinate measuring machines was discussed and

demonstrated in the laboratory and at the

computer terminals. Programs written in BASIC and FORTRAN for these calibrations

were furnished to each participant. The

general comment at the conclusion was that

this type of seminar be conducted at least once a year.

4.4.6 Analysis of Data Base

It is evident from looking at the results

of some recent "round-robins" that the claims

of industry to measure accurately objects

other than simple end standards are optimistic. Even though gage blockSgare available

in accuracies of a part in 10 , not many industrial labs have the capability to transfer these measurements to other artifacts

with any great precision and accuracy.

The precision of instrumentation today

far outpaces the capability of personnel to utilize these devices fully in accurate dimensional measurements. In many cases ac- curate dimensional measurements are needed

to satisfy functionality requirements.

65
In many cases the industrial contacts which

we made yielded no earth-shattering news con- cerning needs for more accuracy. The main

area of concern was need for more help with

the day-to-day mundane problems. One solution seems to be a concerted effort to publish more articles in journals to describe

our philosophies of measurement and also various processes.

The main area of impact which new instrumentation is having in dimensional measurements is in the surveying field. Tapes are

still used quite extensively in the industry,

mainly by private individuals, but in the

past year low cost electronic distance mea- suring devices have been revolutionizing the

surveying industry. With these devices many

surveyors have ranges of over one kilometer

with accuracies limited only by atmospheric

corrections. It has been predicted by one tape manufacturer that sales and production

of tapes might possibly see a sharp decline

in two to seven years because of these devices. There is probably a residual beyond

which tapes will be safe but it should be

interesting to watch the developments.

The computer has proven to be a valuable

tool in the area of inspection and quality

control. If tied into an automatic gaging

system, the computer can print out the inspection result of every part. The computer

is also a valuable tool for sampling and control. The process can be set up so that if

the production process is under control, no action will be taken, but if a parameter

changes, corrective action may be taken.

The computer can also be a vital tool in

the use of coordinate measuring machines. As the artifact is probed, the computer can compare the dimension measured against a nominal

dimension and record the deviations.

Many manufacturers claim that the resolution of their units may be within 50 or 100

microinches. Not many machine tools can produce to these accuracies. There are screws,

lead screws, beds, ways, spindles, and columns made of metal and subject to tolerances.

All of these play a role in determining the

final machining capability which is the one parameter of primary concern. Thus it behooves the user to know what can be obtained

from his machine.

From communication with various industrial concerns we have seen that the need of industry for the next three to seven years in dimensional measurements is in the area of better measurements in three dimensions. There

are many measuring machines now on the market today but most of them have the fault

that inaccuracies are defined in terms of one

axis. There is no assurance that if you

start at point (1,1,0) and terminate at point

(0,0,1) in a working volume that your inaccuracy can be expressed as linear combinations

of the individual axis errors. What is

needed are methods to characterize these er- rors. This is under development now at NBS

with the 3-Dimensional facility. One of the

main purposes of the study of the National

Measurement System is to find efficient means

to disseminate our work to the people who

need it as our project progresses.

4.5 The Future

Central to the NBS program in length and

related dimensional metrology is the provision of adequate calibration services to the

national measurement system. We view the

term adequate as the principal challenge. We must be aware of the changing needs of our customers and support sufficient development

effort to be prepared to meet new needs as they occur while at the same time we must

continue to supply the traditional services

as long as a real need exists. Continued

self-education in our specialties is also a major goal

.

To deal with this dichotomy, we have structured the section into a series of interwoven

service and development tasks so that the ex- pertise of all is available for both service

and research functions. We hope in this manner to avoid the intellectual stagnation of

the "test house" as well as the ivory tower

mentality that can plague a research elite.

4.5.1 Current Major Technical Projects

One of the major programs underway is the

development of a 3-dimensional measurement

capability. The best three axis measuring

machine available was purchased and interfaced with a minicomputer; the necessary

software is being developed. To eliminate

machine errors due to structural bending as the table moves, five channels of laser interferometers are used as the readouts instead of relying on the machine screws. To reduce errors due to thermal effects, all

heat producing elements such as the motors

and clutches are water cooled. A sophisticated temperature measuring system is being

installed to monitor the temperature of various parts of the machine as well as the item

being measured. It is estimated that this

capability will be completed during 1975.

A long range (0-4 inches) gage block

comparator has been developed which uses a laser interferometer as the read-out device.

This instrument has the advantage that only

one master block is required to calibrate a complete set of gage blocks.

A similar measuring instrument has also

been developed using the same principle to measure balls and thread wires. Both machines

66
are operational

A non-contacting gage block comparator has

also been developed but at this time is still

under test.

4.5.2 Distribution of Effort

The current and projected distribution of

effort for Length and Related Dimensional

Measurements is depicted in figure 4-20. Our

inputs are broadly classified into four areas:

(1) Intellectual - The reason for our being

(Definition of Meter).

(2) Internal NBS - These are areas within

NBS with which active cooperation is necessary.

(3) External Customer Requirements - Includes

all users of our routine calibration services

as well as users of our specialized measurement capabil ities.

(4) External Information - Comes in the form

of society interaction, publications, trade

journals, personal visits, and participation

in standards organizations.

The outputs are broadly broken into three

areas and "loose" percentages have been applied to indicate how these areas relate to the total output of Length and Related Dimensional Measurements.

(1) Calibrations - One of our functions is

the providing of services to external and

internal customers for fee. The factor of

1^% is an average and may fluctuate from time

to time. By looking at funding and spending

for FY 1974 we see:

In the area of Length

4-1/4 man-years Research & Technical Support $154.4 K 3-1/2 man-years Calibration effort $ 73.0 K

In the area of Dimensional Technology

8 man-years Research & Technical Support $242.4 K

2 man-years Calibration effort $ 37.0 K

(2) Information - The area of providing information through publications, membership in

societies, attendance at various meetings,

etc. constitutes approximately 15'= of our output currently.

(3) Specialized Measurement Capability - Most

of our time is devoted to development, con- struction, and check-out of new instrumentation for furthering the state-of-the-art and

increasing efficiency at NBS for making measurements. We also spend a great deal of

time in the design and implementation of mea- surement algorithms to enhance the systems

approach to making measurements. (Many of

these have and will find increasing use in

the industrial conmunity . ) A current project

underway with university/government/industry

cooperation is an R & D study of the dimensional stability of optical materials over a long period of time. Several spin-offs from

this project such as more sensitive interferometers are expected to emerge.

It is expected that inputs in the areas of

external information will be increased substantially in the future. We expect to develop better contacts with various societies,

publications, and research and standards or- ganizations. This fact will be mirrored in our output percentages for information be- cause the Section plans to develop more publications in the areas of dimensional measurements and to disseminate them more efficiently.

Continued stronger interactions with industry

will be developed.

Calibrations will no doubt remain reason- ably stable with the exception of some in- crease in workload due to the metric conversion by the nation. It is not known what effect the current energy crunch will have upon

the ability of industry to send items in for

calibration, but it should be interesting to observe for the next few years.

Our future, however, appears to lie predominantly in the area of specialized mea- surement capability. Since industry is con- verting to numerically-controlled machines

and automated measuring machines for inspection and quality control, it seems our current work of pushing algorithm development

may be expanded in the next few years. It seems imoerative that we keep current by

continued interactions with industry, government, and universities.

4.5.3 Time Table for Continuing Analysis and

Acquisition of Data for the National

Measurement System

Plans for the future include the following:

(1) Further acquisition of the data base

through customer interchanges either by letter, personal visit, or telephone.

(2) General interest paper to be presented

to the Inspection and Quality Control Division of SME on National Measurement System

in either first or second quarter.

(3) Continued interaction with the Aerospace

Industries Association and preparation of a questionnaire to be circulated within their

membership by third quarter.

(4) Continued interaction with Metrology Division of the American Society for Quality

Control

(5) Preparation and submission of an over- view article for trade journals such as Qual-ity Marnagemer.t & Enginsaringj Manufaaturing Engineering & Management, or American

Machinist (McGraw-Hill) to be completed by

second or third quarter.

67
INPUT

information

ADA ASTM SMt ASQC NMTBA NCSL

PUBUCAIIONS

M( IHOLUGIA

QUALITY MANAGEMENT & ENGINEERING

APPLIED OPTICS

OPTICAL ENGINEERING MEASUREMENT TECHNIQUES

A MERICAN MACHINISl MACHINE DESIGN MACHINERY

• UNIVERSITIES

• MfSlARTH nRtANI/AIIDN!-

• ADVISORY PANH

INSTRUMENT MANUFACTURERS

• PERSONAL VISITS

• STANDARDS ORGANIZATIONS

ANSI 889, OPTI METRIC

API

customer requirements

• INDUSTRY

• OTHER GOVERNMENTAL AGENCIES

• UNIVERSITIES

• INDIVIDUALS

intellectual

DEFINITION OF METRE

internal

IBS OFFICE OF MEASUREMENT SERVICES

OFFICE OF WEIGHTS & MEASURES QUANTUM METROLOGY

OPTICS & MIRCOMETROLOGY

INSTRUMENT SHOPS STANDARD REFERENCE MATERIALS

PRESSURE & VACUUM SECTION

FLUID MECHANICS SECTION MASS & VOLUME SECTION

NBS LENGTH &

RELATED

DIMENSIONAL

MEASUREMENTS

specialized measurement capability information

• TECHNICAL SOCIETIES

• PUBLICATIONS

• COLLEGES/UNIVERSITIES

• RESEARCH ORGANIZATIONS

• STANDARDS LABS

• INSTRUMENT MANUFACTURERS

• STANDARDS ORGANIZATIONS

• NEW INSTRUMENTATION

• MEASUREMENT ALGORITHM DEVELOPMENT .60 .15

• R S DCORNING

UNIVERSITY OF ARIZONA NASA

1-501 (.301

.25

(.201 calibrations

ALLOW INDUSTRY TO MAINTAIN INTERCHANGEABILITY - 65 OTHER GOVERNMENTAL AGENCIES 23 R&D ALSO UNIVERSITIES 05 INDIVIDUALS 02 INTERNAL (NBS) 05

OUTPUT

.-- CURRENT &

(.-) PROJECTED

DISTRIBUTION OF EFFORT

Figure 4-20. Input-output for NBS-length and related dimensional measurements.

68
5. SUMMARY AND CONCLUSIONS

The determination of length and related

dimensional measurements constitute the

largest group of measurements made in science, manufacturing and technology. We have

shown that length and related dimensional

measurements have impact upon many areas of

the economy. We have also shown that the

National Measurement System is viable and is

adaptable in conforming to the changing re- quirements of industry. The greater accuracy

requirements of some industries brought new measurement techniques into use, e.g. the

fringe counting laser interferometer systems

now used in many tool rooms and metrology

laboratories. We have found no deficiencies

in the system but only in the knowledge and

capabilities of individuals or the measurement technique that they use, as shown in the comparison measurement on audit packages

that were made by the various standards laboratories.

Through the Measurement Assurance Program (MAP) NBS is playing a vital role in

monitoring government, industrial, and commercial standards laboratories measurement

systems and techniques to keep their measurement precesses in control . The increasing

use of the computer aided three dimensional

(3D) measurement facility has reduced the

calibration cost of some of the services. Of

equal importance, it has reduced the "turn

around time" of the physical standard and

returned it to the National Measurement System with minimum inconvenience to industry.

Our contacts with industry at the International Machine Tool Show, 1974, only re- verified our position that the publication of

NBS calibration procedures written at the

technician level is the type of document most

useful to the metrology community that we

serve. We will continue to publish our ex- isting calibration procedures for all the

length and related dimensional measurements

that we offer. Since NBS does not have a formal mailing list of interested parties,

we intend to publish a list of the available

papers in the various trade magazines with

information on how and where to obtain them.

Plans for the immediate future call for

adapting more of our standard calibrations

to our 3D facility. A short range, (0-4in.)

gage block comparator was recently designed

and at present is under evaluation. Another

long range (4-24in.) comparator is in the

preliminary design stage. This instrument

will be in operation in late 1976. Since

the instrument makers are reluctant to invest their research funds in new measurement techniques because of the limited

demand and the old adage of metrologists

"but we've always done it this way," NBS

must lead the way in developing new mea- suring instruments using the most recent

discoveries of the scientific community.

69
APPENDIX A. METHODOLOGY OF THE STUDY

Four primary

^anism were used

understanding of

System:

(1) An Industry

interviews with

(2) Contacts wi

publications in

(3) "Outreach"

(4) Literature

robin" or audit

categories of contact mechto develop our knowledge and

the National Measurement

canvass and also telephone

selected people,

th technical societies and/or

the area of interest,

Porgram,

search for pertinent "roundpackages .

A(l) - The canvass of industry was an attempt

to establish a preliminary data base to ans- wer a few of our basic questions concerning

the importance of dimensional measurements.

The canvass consisted of two parts: first,

an informal question letter and/or telephone

interviews with responsible individuals within an organization. In all cases no formal

questionnaire was sent "blindly" into an organization. A high-ranking contact within

a company was first established within our

area of interest (sometimes requiring several

iterations); a preliminary telephone interview was conducted; and second, if the need

existed, a letter outlining other questions

was subsequently sent to the interviewee for

his consideration. By adopting this system,

it appears we may achieve 95-100% participation with the industries we contacted.

We took an objective look at our NBS Customer Profile to select the SIC categories

which could be interpreted to imply "firstorder measurement-intensive" industries. By

selecting companies which then possessed these

SIC codes for their products or services ren- dered, we were able to develop a systematic

"sample" of the users. However, the resulting

list does not lend itself to conventional sta- tistical analysis because: (1) that was not

the original purpose, and (2) the size of

the population cannot be proven to be a ran- dom sampling of the overall distribution.

The size of the companies represented

range from a low of less than $1 million to

a high of $9.4 billion in value of shipments

in 1972. Figure A-1 shows the cross-section

profile of the participating companies in terms of two-digit SIC codes. These companies represent total sales of over $15.2 billion. The codes are:

Table A-1. SIC codes of canvassed companies.

SIC

Frequency Code

35

36

Description

Machinery, except electrical

Electrical machinery, equipment, and supplies

28

37

34

39

38

Chemicals and allied products

Transportation equipment.

Ordnance & accessories

Fabricated metal products

Misc. manufacturing indust.

Professional, scientific, I controlling instruments,

photographic & optical

goods, watches & clocks.

i i

28 34 35 36 37 38 39 SIC CODE

Figure A-1. Cross-section of industry canvass on dimensional measurements from com- panies with 1972 sales of $15.2 billion total.

A comprehensive listing of representatives

from companies we have contacted by these

methods is given at the end of this appendix.

The form of the survey was standardized to some extent to facilitate easy interpretation

of the results. Questions were changed if

they were not appropriate to the interviewee's

particular case. For the most part, the interview (letter and/or telephone) was conducted

as follows:

(1) Introduction of person or persons

(2) Purpose of study of National Measurement

System

(3) Inquiry as to the nature of the company

(4) Economics of performing dimensional mea- surements accurately

(5) Types of personnel and instrumentation

involved in dimensional measurements

(6) Any foreseeable problems in dimensional

measurements

(7) Opinion of NBS and how you think NBS can better serve the system

(8) Thanks and expression of desire to con- tinue dialogue.

In some cases where we wanted more information a formal letter was sent to incividuals already contacted (see fig. A-2).

A(2) - Contacts with Technical and Trade Societies and Journals. The methodology was simply to telephone, write or meet the re70
Dear : We wish to thank you for your willingness to provide data for our assessment of the National Bureau of Standards' role in the National

Measurement System. As we mentioned before,

our main area of focus is the subject of

length and length measurements. A few of the

questions we are attempting to answer are: Do NBS measurement services meet the needs

of US industry? If not, where and how can these services be improved?

Are there predictable developments that

would create a need for standards and/or services not now available?

To obtain a focal point, we have assembled

a questionnaire which will serve for the development of a more in-depth probe of your

needs. We would ask that you assemble various individuals within your organization-from

management to technicians-to discuss the various questions and obtain a spectrum of answers. Please answer and comment on as many

of these questions as possible. Your answers

may be very informal - use a pencil if you'd

like, and add any additional information that

you feel might be helpful. We assure you that

all your answers and comments will be strictly confidential

If you have any other comments on problems

associated with dimensional measurement,

please write them down. We asked for your

help and you are entitled to ours.

QUESTIONS

(1) Explain the nature of your business in terms of products and services rendered.

(2) How much money and/or man-years is ex- pended annually by your company in the mea- surement of some facet of length? Can you

give a rough estimate of the amount of money

invested by all companies in the measurement

of length?

(3) What types of length instrumentation are

used in your plant? How do you proceed in

the calibration of these instruments?

(4) What type of personnel do you have involved in length measurements? Is there any

type of additional training you would like

these personnel to receive and in what area?

(5) If you had unlimited funds for development of new instrumentation, what precision

and accuracy range would you be interested in achieving?

(6) Do you find pneumatic gaging adequate

for certain applications in your plant? In what areas is this form suitable and in what

areas is it not?

(7) If you use the services of NBS, please

state in what way? Why do you use these ser- vices? Do you f""" these services adequate

or inadequate? I- ase tell how you feel these

might be improved.

(8) Do you feel that NBS gives enough assist- ance to various manufacturers around the

country? Please explain how you think this

situation might be improved.

(9) Are there any problems in your manufacturing processes where an improvement in the

accuracy or precision or method of length

measurement might help raise productivity?

Do you think consultation with NBS could help?

If not, why not?

(10) In what areas do you find foreign com- petition? What are their most interesting

products and what do you foresee as their

most innovative products in the future?

(11) If some of your personnel attended the

NBS Dimensional Conference in 1972, what were

their impressions? How could the conference

have been improved? Would you like to see such a conference repeated every few years?

Why?

(12) What type of training seminars and/or

publications would you like to see emanate

from NBS? In what areas of interest? Toward

what level of personnel should these be geared?

Where do you feel would be the most effective

and efficient place to publish our work?

(13) Do you feel that if you had to "prove"

to accuracy of your measurements in a court

of law, you would have sufficient evidence to convince the jury? What type of evidence

would you present for your defense? Is this

type of proof important to you?

(14) What is your current concept of NBS

(please include different views of your people)? How do you visualize NBS as you think

it should be?

FINAL - On the scales below, rank the dimensional measurements you perform with the following symbols: X - CURRENT (what you can now do) 0 - FUTURE (what you will need in 5-10 yrs.)

1-Dimension 1-Dimension 2-Dimension 2-Dimension 3-Dimension 3-Dimension

Precision Accuracy Precision Accuracy Precision Accuracy

Not

Important

Very

Important

Figure A-2. Canvass cover letter and questionnaire.

71
sponsible officials or editors. Results have

been reported in section 4.4.2.

A(3) - "Outreach" Program. In the past few

years, the management of the Dimensional

Technology Section at NBS started to "reach

our" to the outside world by sending personnel on fact-finding missions to various com- panies around the country. Anytime someone

visits a part of the country on either personal or business reasons, the area is usu- ally searched to find any interesting visits

that might be made. We have a colored map

in our Section Office with the places visited depicted by colored pins so that one

can easily see the far-reaching results of

this program.

A(4) - Literature Search. One way of assessing the needs of industry in terms of dimensional measurements is to look at the results

of surveys which are conducted periodically

by interested indiviudals. When the surveys

are in the form of audits, i.e., artifacts

which are sent to various laboratories and

companies to be measured, then much more information is gained.

We have found three pertinent surveys

which tell us some things concerning the

ability of industry to measure dimensional

objects

.

(a) A survey conducted in 1958 and 1959 by

the Aerospace Industries Association.

(b) A survey conducted in 1961 by the Na- tional Physical Laboratory, which included

artifacts sent to more than 40 companies in

England.

(c) A current NCSL Audit Package sent to more than twelve of the best laboratories

around the United States: Results of this

survey have been presented in section 2.3.

Personal and Corporate Contacts

Mr. Ernest Weber

Micro-1 ine Inc

.

Division of Bausch & Lomb

Box 938

Jamestown, New York 14701

(716) 483-7182

Mr. Conrad Fahlman, Director Quality Con.

Brown & Sharpe Manufacturing Company

Industrial Products Division

North Kingston, Rhode Island 02852

(401) 884-3000

Mr. Ed . CI incher

Metrology and Primary Standards Lab.

Chrysler Corporation

Highland Park, Michigan 48203

(313) 956-6672

Mr. R. R. Sandman, Mgr., Physical Stds.

Mr. Paul Ackermann, Mgr., Engrg. Stds.

Mr. C. Carter, Director, Mach. Tool R&D.

all with the

Cincinnati Milacron Corporation

4701 Marburg Avenue

Cincinnati , Ohio 45209

(513) 841-8409

Mr. Fred Hutcherson & Mr. Hugh Turnball

Continental Machines

Savage, Minnesota 55378

(612) 890-3300

Mr. William Bauer, General Manager

Deltronic Corporation

929 Baker Street

P. 0. Box 2155

Costa Mesa, California 92626

(714) 545-0401

Mr. Calep Hathway

Scientific, Electrical, Optical Ins rs. Department of Commerce

Washington, D.C. 20230

(202) 967-2312

Mr. Bob Hunsburger

Department of Commerce

Transportation and Capitol Equip., Div.

Metal working Machinery & Machine Tools

Washington, D.C. 20230

(202) 967-5611

Mr. John Musgrave & Mr. Bob Wasson

Department of Commerce

Bureau of Economic Analysis

Washington, D.C. 20230

(202) 967-3230

Mr. Thomas Gray

Federal Products Corporation

1144 Eddy Street

Providence, Rhode Island 02901

(401) 781-9300

Mr. Lyman W. Higgins, Director of Mktg.

Gaertner Scientific Company

1201 Wrightwood Avenue

Chicago, Illinois 60614

(312) 281-5335

Mr. Max Unis

Gage Lab Corporation

Philadelphia, Pennsylvania 19115

(215) 355-5420

Mr. George E. Nateau

General Electric

Aircraft Engine Operations Division

1000 Western Avenue

Lynn, Massachusetts 01905

(617) 594-0100

72
Mr. A. J. Woodington, Chief, Meas. Con.

General Dynamics

Convair Aerospace Division

P. 0. Box 1128

San Diego, California 92112

(714) 277-8900

Mr,. J. Rochette

General Motors

New Departure Hyatt Bearings

Bristol, Connecticut 06010

(419) 626-2120

Mr. Joel D. Gruhn, Physicist

Hutchinson Industrial Corporation

40 West Highland Park

Hutchinson, Minnesota 55350

(612) 879-2371

Mr. W. N. Clausen, Reg. Sales Engr.

Keuffel & Esser Company

1521 North Danville St. Arlington, Virginia 22201

Mr. Marshal Brown, Director of Engr.

Laser Systems, Inc. Tullahoma, Tennessee 37388

(615) 455-0686

Mr. Ferris S. Chandler

Lufkin (Div. of Coooer Industries)

Box 728

Apex, North Carolina 27502

Mr. Ed . Hagel , Manager

National Astro Labs

2201 North Hollywood Way

Burbank, California 91504

Mr. Coleman

Navy Western Standards Laboratory

Pomona, California 91766

(714) 437-6991

Mr. Charles Muirhead

National Ocean Survey

Oceanographic Division

6001 Executive Blvd.

Rockville, Maryland 20852

(301) 496-8501

Mr. Nelson Wilkins

Oak Ridge National Laboratory

P. 0. Box X Bldg. 2525

Oak Ridge, Tennessee 37809

Mr. C. G. Erickson, Manager of Engrg.

Pratt & Whitney Small Tool Division

Charter Oak Boulevard

West Hartford, Connecticut 06101

(203) 233-7591

Mr. J. C. McKinney, Jr., Chief

Army Standards Laboratory

U.S. Army Metrology and Calibration Ctr.

U.S. Army Missile Command

Redstone Arsenal, Alabama 35809

Mr. Hugh Collins, Manager of Engrg.

Webber Gage Division

L. S. Starrett Co. 24500 Detroit Road

Cleveland, Ohio 44145

(216) 835-0001

Mr. Richard A. Newton, Chief Inspector

L. S. Starrett Company

104 Crescent Street

Athol , Massachusetts 01331

(617) 249-3551

Mr. Doug Garside, Manager of Engrg.

Mr. Robert Lamport, Head of Q.C.

The Van Keuren Company

176 Waltham Street

Watertown, Massachusetts 02172

C6I7) 926-1450

73
APPENDIX B. SUMMARY OF BACKGROUND DOCUMENTS

1. Title : By:

Publ ished : Results or

Federal

Federal

Fed. Spec. GGG

Key Findings

Specification - Gage Blocks and Accessories

Supply Service, General Services Administration

G-15B, November 6, 1970.

Effect:

specification covers precision gage blocks up to and including

in length, and accessories, in either the inch or metric system

for use by laboratories, inspection shops or as work gages for high accuracy maching operations. Notes for usage and definitions of terminology may be found in

section six.

Federal specification coverage . Federal specifications do not include

all types, classes, and styles of commodity indicated by the titles of

the specifications, but are intended to cover only those used by the

Federal Government.

1.1 Scope . This

20 inches (500mm)

1.1.1

1.2 Classification,

1.2.1 Style, grades, classes

lowing styles, grades.

Styles (shapes): Style

Style

Style

Grades: Tolerance grades:

and types . The gage blocks shall

classes, and types, as specified:

1. Rectangular.

2. Square, with center accessory hole.

3. Other shapes as specified.

0.5 (formerly grade AAA),

be of the fol

Grade

Grade

Grade

Grade

(formerly grade AA)

.

(formerly grade A+)

.

(compromise between former

grades A and B)

.

Accuracy level grades: 1 microinch (25 nanometres).

2 microinch (50 nanometres).

Classes and types (material): Class I. Steel.

Class II. Faced blocks, steel.

Type (1) Chromium plated.

Class III. Type (1)

Type (2)

Class IV. The preceding material is quoted directly from page 1 The effect of this specification

chased by the Federal Government

Carbide

.

Chromium carbide.

Tungsten carbide.

Other material (as specified),

of a 28 page specification,

is to assure the quality of all gage blocks pur-

, The specification is available from Business Service Centers at the General Service Administration Regional Office in Washington, DC.

2. Title: NBS Handbook 44, Fourth Edition

As adopted by the National Conference on Weights and Measures

U.S. Government Printing Office, for Department of Commerce, NBS.

Approach Used : Committee consensus within National Conference on Weights and Measures, with

staff support from NBS.

This handbook covers the specifications, tolerances, and other technical requirements for commercial weighing and measuring devices. The publication may be purchased from the United States Department of Commerce, Washington, DC. Provides the technical "bible" for the state and local weights and measures officials.

By:

Publ ished:

Scope :

Effect:

74
APPENDIX C. MANUFACTURERS OF

DIMENSIONAL ARTIFACTS **

FLATS , optical

AGA Corp

Acme Scientific Co, Div. of Acme Ind.

American Gage, Sub. of Katy Ind.

Ash Mail Order System, Inc.(d)*

D.I.L., Inc.(d)

Davidson Optronics, Inc. DoAll Co. Ealing Corp. The Optics Div.

Edmund Scientific Co. Gaertner Scientific Corp.

Group 128, Inc. Infrared Industries, Inc. International Micron Optics, Div. CharvozCarsen Corp.

Itek Corp.

Jodon Engrg. Assocs., Inc. Katy Industries

Laser Technology, Inc. Ledford Machine & Gage Lab., Inc. Lenox Instr. Co., Inc., Unit of Esterline

Opto-Metric Tools, Inc. Owens-Illinois Inc., Fecker Systems Div.

Perkin-Elmer Corp., The Laser Products Div,

Perkin-Elmer Corp., The Instrument Div.

R.I.S. Inc.(d)

Radiation Equipment Co. Rank Precision Inds., Inc. Shumway Optical Instruments Corp.

Speedlap Supply Co. Starrett Co., The L.S.

Swiss Precision Inst., Inc. Van Keuren Co. , The

Webber Gage Div. of The L.S. Starrett Co. Zeiss Inc. Zygo Corp.

GAGE BALLS

AA Gage Div. US Industries, Inc. American Gage, Sub. of Katy Industries

Ash Mail Order System, Inc.(d)

Bendix Corp., The Automation and Measurement Div.

D.I.L., Inc.(d)

DeKalb Precision Inds., Inc. Deltronic Corp.

Dorsey Gage Co . , Inc

Ind'l. Tectonics, Inc., Ball Div.

Katy Industries

Micro Surface Engineering Co. Penniman Inc., Elisha

Precision Industries, Carbide Div.

Ral mike's Tool-A-Rama

Schmitt Co. Inc. , R.I

Siber Precision Inc.(d)

Size Control Co. a Katy Industries Co. Swiss Precision inst. Inc. Tietzmann Tool Corp.

Van Keuren Co. , The

*(d) designates distributor.

GAGE BLOCKS

Al ina Corp. (d)

Ash Mail Order System, Inc.(d)

Boice Div. Mechanical Technology Inc. Brown & Sharpe Mfg. Co., Ind. Prod. Div.

CEJ Gage Co.{d)

Carey Machy & Sup. Co., Inc.(d)

Collins Microflat Co. Inc. Colt Inds. Pratt & Whitney Small Tool Div.

Custanite Corp. , The

D.I.L., Inc.(d)

DeKalb Precision Inds., Inc. Dearborn Gage Co. Detroit Testing Lab.

DoAll Co. Fowler Co . , Fred V

International Micron Optics, Div. CharvozCarsen Corp.

Jonard Industries Cor. Julie Research Labs., Inc. Kuroda Precision Ind. Ltd.

Ledford Machine & Gage Lab., Inc. MTI Corp.

Montgomery & Co. Inc.(d)

Paci f ic Gage Co . , Inc

Precision Devices, Inc. R.I.S. Inc.(d)

Ral mike's Tool-A-Rama

Rank Precision Inds., Inc. Rutland Tool Supply Cj., Inc.(ci)

Siber Precision Inc.(d)

Starrett Co . , The L.S.

Swiss Precision Inst., Inc. Van Keuren Co . , The

POLYGONS , optical

AA Gage Div., U.S. Industries, Inc. Bailey Meter Co., Sub. of Babcock & Wilcox

D.I.L., Inc.(d)

Davidson Optronics, Inc. Ehrenreich Photo Optical Inds. Nikon

Instrument Div.

Ledford Machine & Gage Lab., Inc. Starrett Co . , The L.S.

Statham Instruments, Inc., Industrial Div.

Webber Gage Div., The L.S. Starrett Co. Zygo Corp.

RULES , measuring (also see Tapes, measuring)

Ash Mail Order System, Inc.(d)

Brown & Sharpe Mfg. Co., Ind. Products Div.

Brunson Instrument Co. Carey Machy. & Sup., Co., Inc.(d)

Coastal Abrasive & Tl . Co., Inc. Colt Inds., P&W Small Tool Div.

Custanite Corp. , The

D.I.L., Inc.(d)

DoAll Co. Edmund Scientific Co. Fowler Co. , Fred V. General Hardware Mfg. Co., Inc., Div. of

General Tools Corp.

Ledford Machine & Gage Lab., Inc. MTI Corp.

Metra-Tech Inds., Inc. 75
Millers Falls Co . , Ingersol 1 -Rand Co. Pacific Gage Co . , Inc. Panelgraphic Corp.

Pi Tape

Picker Industrial, Div. Picker Corp.

Proto Tool Co. Rank Precision Inds., Inc. Snap-on Tool s Corp.

Starrett Co., The L.S. Yuasa International Inc. TAPES , measuring (also see Rules, measuring)

Ash Mail Order System, Inc.(d)

Carey Machy. & Sup. Co. Inc.(d)

Comparator Chart Engineering

Custanite Corp. , The

D.I.L., Inc.(d)

Ledford Machine & Gage Lab. Inc. Micro Metrics, Inc. Millers Falls Co., Ingersol 1 -Rand Co.

Pi Tape

Proto Tool Co. R.I.S. Inc.(d)

Rank Precision Inds., Inc. Rolatape Corp.

SOS Photo-Cine-Optics, Inc. Snap-on Tools Corp.

Starrett Co. , The L.S.

Yuasa International Inc. TAPES , precision calibrated

Custanite Corp. , The

Panelgraphic Corp.

Pi Tape

Rank Precision Inds., Inc. SQUARES , cylindrical

AA Gage Div., U.S. Industries, Inc. Ash Mail Order System, Inc.(d)

Busch Co . , Inc . , J .C

.

CEJ Gage Co.(d)

Carey Machy. & Sup. Co., Inc.(d)

Collins Microflat Co. Inc. D.I.L., Inc.(d)

DeKalb Precision Inds., Inc. DoAll Co. Federal Products Midwest Davis Gage & Engrg. Co. , A.G.

Fowler Co. , Fred V. Int '1 . Machine & Tool Corp.

Ledford Machine & Gage Lab. Inc. Mahr Gage Co. , Inc.(d)

Montgomery & Co., Inc.(d)

Moore Special Tool Co., Inc. Pacific Gage Co. , Inc

.

R.I.S. Inc.(d)

Rank Precision Inds., Inc. Rutland Tool Supply Co., Inc.(d)

Siber Precision Inc.(d)

Taft-Peirce Mfg. Co., The

Van Keuren Co . , The

Yuasa International Inc.

WIRES , thread measuring

Alina Corp.(d)

American Gage, Sub. of Katy Industries

Ash Mail Order System, Inc.(d)

Bendix Corp., The Automation & Meas. Div.

Bendix Corp., The Industrial Tools Div.

Colt Inds. P&W Small Tool Div.

D.I.L., Inc.(d)

DeKalb Precision Inds., Inc. Deltronic Corp.

Katy Industries

Kromhard Twist Drill Co. Ledford Machine & Gage Lab., Inc. Montgomery & Co., Inc.(d)

0-Vee Gauge Co. Precision Devices, Inc. R.I.S. Inc.(d)

Ralmike's Tool-A-Rama

Siber Precision Inc.(d)

Size Control Co., a Katy Industries Co. Southern Gage Co. Swiss Precision Instr., Inc. Taft-Peirce Mfg., Co., The

United Gage Co. Van Keuren Co . , The

'*Some manufacturers of dimensional artifacts

may have been inadvertently omitted.

76
APPENDIX D. TYPICAL INDUSTRY SPECIFICATIONS FOR RULINGS

SPECIFICATIONS OF RONCHI RULINGS AT 68' F COMMERCIAL GRADE INSPECTION GRADE

PITCH

LINES PER

INCH

ACCURACY

FORMULA

Maximum Error From Any Group

of Lines to any

other Group L

inches away

MAXIMUM

PERIODIC ERROR PEAK TO PEAK

ACCURACY

FORMULA

Max. Error From Any Group of Lines

to Any Other Group

L Inches Away

MAXIMUM

PERIODIC ERROR PEAK TO PEAK

200 .0005 " + .00002" L .000125" .00025" + .00001 " L .000050"

250 .0004 " J- .00002" L .0001" .0002 " + .00001 " L .000050"

500 .0002 " .00001" L .00005" .0001 " + .00001 " L .000015"

1000 .00015" — .00001" L .00003" .0001 " + .000005" L .000015"

1250 .00015" -i- .00001" L .000025" .0001 " 4- .000005" L .000015" 2500 .00015" -}- .00001" L .000020" .0001 " + .000005" L .000012" METRIC

PITCHES

LINES PER

M M

Maximum Error From Any Group

of Lines to any

other group L mm away

MAXIMUM

PERIODIC ERROR PEAK TO PEAK

Max. Error From Any Grcup of Lines

to Any Other Group

L mm Away

MAXIMUM

PERIODIC ERROR PEAK TO PEAK

8 12.5 um + .01 L um 4 gm 6 um + 0.01 L um 1.2 um

10 10 um + .02 L um 2.5 um 5 um + 0.02 L um 1.2 pm

20 5 um + .015 L um 1.2 um 2.5 um + 0.01 L um 0.6 um

40 4 um -(- .01 L um 0.75 um 2.5 pm 4- 0.005 L um 0.4 um

50 4 um + .01 L um 0.6 um 2.5 um + 0.005 L um 0.4 um

100 3 um -i- .01 L pm 0.5 um 2 um + 0.005 L um 0.3 pm

200 2 5 um -1- .01 L um 0.4 um 1.5 um ^ 0.005 L um 0 25 um

MOIRE FRINGE PATTERN USING 500 LINE/INCH RONCHI RULINGS

77
APPENDIX E. STATE LABORATORIES AND CAPABILITIES (PHYSICAL DIMENSIONS)

Laboratories ** ***

ALABAMA DEPT OF AGRI & INDUST X $ ALASKA STATE X $ ARKANSAS WEIGHTS & MEASURES LAB X $ CALIFORNIA BUREAU OF WTS. & MEAS F g

. COLORADO DEPT OF AGRICULTURE X s CONNECTICUT STATE OFFICE BLDG X s DELAWARE DEPT OF AGRICULTURE X s GEORGIA DEPT OF AGRICULTURE X s

[ STATE DEPT OF AGRI, HAWAII X B IDAHO DEPT OF AGRICULTURE X s

ILLINOIS STATE X s INDIANA STATE BOARD OF HEALTH X s KANSAS DEPT OF AGRICULTURE X b MAINE DEPT OF AGRICULTURE F s MARYLAND OFFICE OF WTS. & MEAS. F s COMMONWEALTH OF MASSACHUSETTS X $ MICHIGAN DEPT OF AGRICULTURE X $ MINNESOTA DEPT OF PUBLIC SERV C S MISSOURI WEIGHTS & MEASURES X b NEVADA DEPT OF AGRICULTURE C s NEW HAMPSHIRE BUR OF WTS & MEAS f S NEW JERSEY STATE X s north carolina dept of agri x $ north dakota public serv comm f s oregon agriculture dept f s commonv;ealth of Pennsylvania s

5 c dept of agriculture x b TENNESSEE DEPT of agriculture x B UTAH DEPT OF AGRICULTURE X S VERMONT DEPT Of AGRICULTURE f s •VIRGINIA DEPT OF AGRI & COMMERCE x WISCONSIN DEPT OF AGRICULTURE x B WYOMING DEPT. OF AGRICULTURE f .

'

•Indicates NCSL member

0 Service to Parent Organization ONLY

C Available to Customers m SPECIAL CASES

F Calibration Services Available on a FEE BASIS

X Calibration Services Available on a NO FEE BASIS

(P) for primary standards only

(S) for secondary and/or lest instruments only

(B) for both levels of work.

APPENDIX F. GOVERNMENT AND INDUSTRIAL LABORATORIES AND CAPABILITIES (PHYSICAL DIMENSIONS)

Laboratories

•AEROJET ELECTRO SYSTEMS CO. 0 S •AEROJET NUCLEAR CO. C S WILLIAM AINSWORTH, INC. F •ALLIS CHALMERS MFG. CO. F B AMERICAN ELECTRONIC LABS., INC. F p AMERICAN GEOPHYSICAL i INSTR. F B AMERICAN INSTRUMENT SERVICE, INC F B •AMP, INC. 0

•APPLIED PHYSICS LAB./JHU 0 S •ARGONNE NATIONAL LABORATORY 0 •ARIZONA STATE UNIVERSITY 0

•AUDIO DEVICES, INC. 0 •AVCO CORP. F B AVCO CORP. LYCOMING DIV. F B

78

Laboratories

AVCO CORP.

•BAILEY METER CO

•BALL BROS RESEARCH CORP

BATH IRON WORKS CORP

•BATTELLE, COLUMBUS LABS •BECKMAN INSTRUMENTS., INC. •BEECH AIRCRAFT CORP

•BELL AEROSPACE CO

•BELL & HOWELL RESEARCH LABS. •BENDIX CORP

•BENDIX CORP

•BENDIX CORP

•BENDIX CORP., KANSAS CITY DIV •JAMES G, BIDDLE CO

B & K INSTRUMENTS, INC. •BLANCHETTE TOOL & GAGE MEG CORP

•BOEING CO., AEROSPACE GP

BOEING CO., WICHITA DIV. •BRUSH INSTRUMENTS DIV OF GOULD BURROUGHS CORP

*CAL TECH

•CAL TECH, JPL DSN •CANNON INSTRUMENT CO. •CERTIFIED CALIBRATION LABS., INC 'COLLINS RADIO CO COLORADO ENGINEERING EXPERIMENT •COMMUNICATION SATELLITE CORP, •COMPUTER DIODE CORP •COMSAT LABORATORIES

•COX & COMPANY, INC. •CUMMINS ENGINE CO. •DALMO VICTOR CO "DAYTON T. BROWN, INC •DETROIT EDISON CO. •DOW CHEMICAL CO •DUPONT DE NEMOURS, E. I.

E G & G, INC.

•E G & G, INC,

•E G & G, INC

•EIL INSTRUMENTS, INC. •ELECTRICAL INSTRUMENT SERVICE •ELECTRICAL TESTING LABS , INC. •ELECTRO-SCIENTIFIC INDUSTRIES 'ENDEVCO

EPPLEY LABORATORY, INC. •E-SYSTEMS, INC. •FAIRCHILD CAMERA & INSTRUMENT

•JOHN FLUKE MFG. CO., INC. •FOXBORO CO

•GAGE LAB CORPORATION

•GARRETT CORPORATION GAUGE REPAtR SERVICE

GEN. DYNAMICS, QUINCY SHIP DIV, •GENERAL DYNAMICS CORP. •GENERAL DYNAMICS CORP. •GiNERAL DYNAMICS CORP.

•GEItERAL DYNAMICS •GENERM ELECTRIC CO GENERAL ELECTRIC CO. •GENERAL ELECTRIC CO

•GENERAL ELECTRIC CO

•GENERAL ELECTRIC CO (NASA) GENERAL ELECTRIC CO

GENERAL ELECTRIC ICSS GENERAL ELECTRIC INSTRUMENTATION

•GENERAL RADIO CO GRUMMAN AEROSPACE CORP.

•GUILDLINE INST5 , INC HAMILTON TECHNOLOGY, INC. •HARRIS-INTERTYPE HEATH CO

•HERCULES INC HEWLETT-PACKARD CO , MICROWAVE
Laboratori es *** Laboratories

HEWLETT PACKARD CO. HONEYWELL INC. HONEYWELL INC. HONEYWELL INC. •HONEYWELL INC. HONEYWELL INC. •HONEYWELL INC. HONEYWELL INC, HONEYWELL INC. HONEYWELL INC. HONEYWELL INC. HONEYWELL INC. •HONEYWELL INC. HONEYWELL INC. HONEYWELL INC, HONEYWELL INC. •HUGHES AIRCRAFT CO. HUGHES AIRCRAFT CO. •NT RESEARCH INSTITUTE •INLAND TESTING LABS., INC. •INSTRUMENTS EAST •INTERNATIONAL TELEPHONE i TELEG

ITEK CORPORATION

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APPENDIX G. NORTH AMERICAN DATUM

I. PURPOSE

This report was prepared to present the need for a new general adjustment

of the horizontal control system of North America in order to bring it up

to modern standards as an effective reference datum for present and future

surveying and mapping. The report provides background information, identifies and describes the requirements, and shows the benefits of an updated

National Network. This report also discusses the work activities required

to update the network and recommends a procedural plan to accomplish the

job within a reasonable time frame.

II. BACKGROUND

A. Terminology

The National Network of Horizontal Geodetic Control is composed of

monumented points derived from the accumulated geodetic surveys made

by NOAA, its predecessors, and other Federal and local agencies since

1816. Some of the terminology which will be used throughout this

paper is explained in the following paragraphs:

1. Horizontal Geodetic Surveys - Horizontal Geodetic Surveys are conducted primarily to provide measures of the interrelationships of distance, direction, and location of monumented points.

The location of the points are expressed in terms of latitude

and longitudes. The national system of interrelated points is

called a "horizontal control network" because the correlation

of other surveys is derived from and controlled by the network.

The illustration below shows a brass disk monument, inscribed

with its identifying station name, which is used to mark a control point.

Horizontal Control Station

Monument

.

2. Datum - A Geodetic Datum is the base of reference for the

computation of horizontal control surveys in which the curv- ature of the earth is considered. It consists of five quantities:

the latitude and longitude of an initial point, the azimuth of

a line from this point, and the two constants (polar and equatorial radii) necessary to define the terrestrial spheroid.

80
81
3. The North American Datum - The North American Datur (NAD) is

the base of reference on the North American Continent to which

all geodetic control surveys of the United States, Canada, and

Mexico are related. Collectively, these National Network surveys

are commonly referred to as the North American Datum, The geodetic datum, or starting point, for the North American Datum is

a monumented point in Kansas called Meades Ranch. The latitude

and longitude for Meades Ranch are referenced to the semiaxes

of the Clarke Spheroid of 1866. The Clarke Spheroid of 1866

mathematically defines the spheroid which most closely fits the

geoid (the actual shape of the earth) in North America.

4. Geoid and Spheroid - The geoid is the actual shape of the earth

described by an equipotential surface, or a surface that is

everywhere perpendicular to the direction of gravity. Because

the surface of the earth (the geoid) is irregular, and surveys

must be made on this irregular surface, it is necessary to transform the surveys to a regular surface (the spheroid) to provide

a uniform system of reference. The North American Datum is referenced to the spheroidal surface by geographic coordinates calculated from the dimensions of the equatorial and polar semiaxes,

a. and b. These relationships are shown in Figure 1.

FIGURE 1.

a. Equatorial

semiaxis

b. Polar

semiaxis

Clarke Spheroid

1866

(Meters)

6,378,206.4

6,356,583.8

B. Evolution of North American Datum

Incorporating surveys made for over a century and a half, the geodetic

reference systen of the United States has evolved in a dynamic manner,

both technologically and physically. Like any engineering creation,

the structure requires timely maintenance throughout its life, and

occasionally, a major overhaul.

1. Historical Development - The first official geodetic datum in

the United States was the New England Datum, adopted in 1879,

based on an adjustment of surveys in the eastern and northeastern states and referenced to the Clarke Spheroid of 1866,

with triangulation station Principio, in Maryland, as the origin.

The first transcontinental arc of triangulation was completed

in 1899, connecting independent surveys along the Pacific Coast. In the intervening years, other surveys were extended to the

Gulf of Mexico. The New England Datum was thus extended to the

82
• Geodetic control used for the 1927 adjustment.

Figure 2.

83
south and west without major readjustment of the surveys . in the

east. Following a new adjustment in 1901, this expanded network

was officially designated the United States Standard Datum, and

triangulation station Meades Ranch, in Kansas, was the origin.

In 1913, after the geodetic organizations of Canada and Mexico

formally agreed to base their triangulation networks on the

United States network, the datum was renamed the North American

Datum.

2. North American Datum of 1927 - By the mid-1920 's, the problems

of adjusting new surveys to fit into the existing network were

acute. Therefore, during the five-year period 1927-1932, all

available primary data (approximately 25,000 monumented control

points) were adjusted into a system now known as the North

American 1927 Datum. The extent of the horizontal control used

at that time is shown in Figure 2. The skeletal-like framework

formed 41 loops ranging in circumference from a few hundred to 3,000 kilometers. The average closure of these large loops,

after adjustment, was in the order of one part in 300,000, which

was considered satisfactory to provide b asic control across the

Nation for dependent surveys of that period. The loops of the

framework in the 1927 adjustment confined coverage of North

America to the conterminous U. S. excluding a large part of the

southeastern United States, Canada, Alaska, and all of Mexico.

Shortl y after the eastern part of the adjustment was completed,

and before the results were published, a discrepancy of approximately 10 meters in latitude along the United States border in

northern Michigan was noted. The U. S. portion of the network

in Wisconsin and Michigan was subsequently readjusted to absorb

this discrepancy.

3. Present Status - As the years passed, the geodetic control in

the United States, Canada, and Mexico has been extended and more than 100,000 monumented control points have been added to the network since 1927 as shown in Figure 3. The new surveys

Figure 3. Status of Horizontal Control - United States, July, 1973.

84
divide the large loops into smaller ones and cover the interior

area of some of the loops. These surveys were fitted and adjusted

to the 1927 framework for a number of years without undue difficulty. But later surveys have had to be distorted by as much

as one part in 15,000 (one foot in 3 miles) to fit within the

loops. Analysis showed that errors and discrepancies had accumulated to as much as 10 meters and then compensated by other

discrepancies of similar magnitude over the long distances in

the loops

These discrepancies went undetected until they were finally

isolated through the process of fitting and adjusting. Regional

readjustments were then made to distribute discrepancies over

larger areas so that distortion could be minimized. These

regional readjustments are a patching process that does not

eliminate errors, but rather distributes and minimizes the

impact (see Figure 4.).

Figure 4 Regions of the United States that have required major read justir.ents

Other weaknesses of the 1927 adjvistment include:

1. The old adjustment did not include the Atlantic

Seaboard control.

2. Length control was significantly deficient for the

1927 adjustment.

3. A number of azimuths used in 1927 have been found

to be of inferior accuracy.

4. The control in Alaska was connected to the Datum

during World War II by means of a single arc of

triangulation along the Alaska Highway.

85
5. In some areas of North America, relative horizontal

tectonic movements as great .as 5 cm. per year have

been observed.

This last point is supported by enough evidence to evoke the

suspicion that many geodetic reference points move relative

to each other, in addition to the probable movement of the

continent as a whole. Thus, it is obvious that a geodetic

reference system cannot be considered as something that, once accomplished, will serve for all time without updating.

III. REQUIREMENTS FOR NEW ADJUSTMENT

Since the adjustment of 1927, requirements for the fundamental network

have changed, users of geodetic data and accuracy needs of the users steadily increased. A recent study of an interagency task force on Mapping, Charting and Surveying (MCS) by the Office of Management and

Budget (0MB) , has determined that 39 Federal agencies now conduct sizeable MCS programs which are dependent on the NAD.

Technology has introduced new and improved measuring tools to the surveyor

so that the increased accuracy needs of today, which approach an order of

magnitude greater than those of 1927, can be met. One of the engineering

principles governing the accuracy of horizontal surveys is that the accuracy

of the basic control system must be at least an order of magnitude greater

than the dependent survey. Over the years, the accuracy requirements of

many users have increased from one part in 25,000 to one part in 100,000.

The 1927 NAD generally will support the one part in 25,000 requirements,

but the one part in 100,000 control is available only in limited portions

of the network.

A. Network Users of the 1970 's

The North American Datum has become truly a National base of

in the 1970 's. The range of activities that depend upon or b

from the accuracy and reliability of these data is great. Th

86
following simple listing of activities and users that benefit from

accurate geodetic information is intended to give a qualitative

glimpse of their extent:

• Rural, urban, city, and regional engineers; planning,

construction, and surveying groups; and related data banks

Nationally coordinated transportation systems and other

activities using geodetically controlled coordinates

All surveys and negotiations for boundary definition,

national or international - including, in the United States,

the individual states and their political subdivisions

.Surveys and planning for water resources, highways, and

utilities

• Mining and related engineering surveys

• Siting and national and international navigation systems

• All large-scale mapping and charting work

• Scientific users Federal work; Federal agency control requirements assembled

by the Federal Coordinator for Geodetic Control and Related

Surveys exceeded 270,000 square miles in area for FY 1975.

These requirements are listed in Table 1., and they are all

dependent on the NAD.

TABLE 1.

Dept. Agency

FEDERAL AGENCY REQUIREMENTS

NORTH AMERICAN DATUM HORIZONTAL CONTROL

F. Y. 1975

Program Requirements

Area of Control

(Square Mile)

DOI Geological Survey

DOI Bureau of Land

Management

Tennessee Valley

Authority

DOA U.S. Forest Service

National Map Series

Land and Resource

Management

Power Plant Siting;

Crustal Movement

Forest Management

and Conservation

23,600

67,400

15,750

68,000

DOC

DOC

HUD

DOD

Soil Conservation

Service

National Oceanic and

Atmospheric Administration

Corps of Engineers

Agricultural Program

Monitoring & Admin.

Marine Surveys & Charts;

Aeronautical Charts;

North American Datum

Maintenance & Update

Urban Development

and Renewal

7,000

Public Works

33,600

600

54,300

TOTAL 270,950 Sq. Miles

87
Many of these new demands on the NAD stem from urban area expansion

and renewal, extension of national and international transportation

and navigation systems, land use changes and jurisdiction, etc.,

all of which have caused an expansion of Federal programs such as those of the Departments of Housing and Urban Development, and

Transportation.

Advanced earth science studies have led many scientists to believe

that we are on the verge of understanding fundamental earth processes

that relate to mountain building, volcanism, and earthquake mechanisms. Historically, periodic updating and evaluation of the geodetic

datum have provided the only measurements of physical changes in

the earth's crust in North America. New measurements and a new

adjustment of the NAD will provide updated and new information

necessary for the furtherance of these studies.

B . Economic Considerations of a New Adjustment

The economic ramifications for a new adjustment of the North American

Datum have increased just as the number of agencies, programs, engineers, surveyors, and scientists who depend upon the datum as a base

of reference have increased since 1927.

The cost of heavy construction, modern highway systems, communication

networks, working satellites, urban renewal, complex record manipulation systems, etc., has greatly advanced requirements for assurance

and reliability in the datum. Electronic distance measuring equipment,

optical reading theodolites and both small and large electronic com- puters are commonly used by surveyors, engineers, data managers, and

decision-makers. This relatively new technology is providing necessary

accuracy and capability for the increased utilization of the National

Datum by users, both new and traditional.

An estimate of the benefits from more accurate and more dense control

can be derived by analyzing the costs associated with actual use of

the control. The cost of new construction in the United States is

something in excess of $80 billion annually. Control surveys of some

type are required for all construction. Ratios derived from exerpience

in engineering and land survey expansion show that 10 percent of new construction requires precise control and that one percent of the con- struction costs would be charged to the survey activity. Thus, of the

$80 billion now spent annually for construction, $80 million is spent

on survey work. Improved accuracy and increased density of the Federal

Control Net would reduce these costs by 25 to 50 percent and an estimated annual benefit of $20 to $40 million would be realized. This is more than 10 times the estimated annual incremental cost of the proposed

new adjustment.

The recently completed 0MB Task Force report on MCS activities states

that Federal agencies expend more than $300 million annually for civilian

MCS products. About $75 million of this amount is for surveys which are affected by the accuracy and reliability of the National Network,

and $9.4 million of that amount was spent in 1972 for horizontal control

surveys that would benefit directly from a new network adjustment.

Figure 10 from the 0MB report shows an approximation of the benefits to be

derived to the Federal agencies by increasing the expenditure level in

order to complete a new adjustment in the next five years. The 0MB report

indicates a $1.2 million increase level between 1974 and 1979 would

complete an adjustment of 90% of the conterminous 48 States, whereas NOAA's new adjustment plan provides for completion of 100% of the 48 states with

an increase level of $1.5 million between 1975 and 1980.

88
FIGURE 10 SAVINGS

from a NEW ADJUSTMENT OF HORIZONTAL CONTROL

YEARS

C. Conclusions and Recommendations

The overall conclusion is that a new general adjustment is necessary;

indeed, it is overdue. Such an adjustment would provide benefits to the Nation that would be more than commensurate with the costs.

NOAA endorses the 1971 NAS/NAE report which concluded that "a new

adjustment of North American Geodetic Control is necessary." — and

summarized, — "it is clear that a new adjustment will have to be

made in the next decade or half-decade." Additionally, the 0MB Task. Force on Mapping, Charting and Survey Activities in Federal civil

agencies concluded that a new general adjustment should be completed

as soon as is practicable, and the reliability afforded by updating

the network will reduce the cost of mapping and surveying operations

throughout the Nation.

The concern and interest of other agencies in updating the North

American Datum is demonstrated by their participation in contributory

studies, symposia, and field operations. The Worldwide Satellite

Triangulation Network was accomplished by the Departments of Commerce,

Defense, and NASA. Likewise, the DoD has performed segments of the

Precise Transcontinental Traverses and the Geoceiver (Doppler)

measurements, necessary for a new adjustment.

Since the Canadian and Mexican National Geodetic Networks are connected

to the North American Datum, the new adjustment is also an international concern. Both bordering goveninents cooperated in the Worldwide Satellite Triangulation project and Canada provided manpower and

transportation for observation teams. Moreover, the University of

New Brunswick in Canada is sponsoring an International Symposium on

the Redefinition of the North American Geodetic Network in May, 1974.

In view of the overwhelming support documented by the NAS/NAE report,

the 0MB study and testimony voiced by professional and scientific

communities, NOAA recommends that a new general adjustment over all

the conterminous states be completed by 1980.

89
Electronic Distance Measurements from a Portable Tower.

Recent studies by NOAA show that a new adjustment could be completed

by 1980 if the work were accelerated with new resources starting in

1975. Completion of the tasks involved in the new adjustment will

require an investment of approximately $16 millions over the next five

years, of which $7.5 million new money is required. The major tasks

involved in an adjustment are:

1. Field surveys and new distance and azimuth measurements

necessary to correct known weaknesses in the North American

Datum.

2. Conversion of all survey measurements and listings to automated

computer format.

3. A new mathematical adjustment of the North American Datum.

90
IV. ELEMENTS OF A NEW ADJUSTMENT

The task of performing a new adjustment begins with the referencing of

geodetic surveys to an ellipsoid of revolution, as defined in Section II,

A, using the dimensions of the earth as a frame of reference. Traditionally, these dimensions have been hypothesized from indirect measurements,

but with earth orbiting satellites, we have measured directly the size and

shape of the earth. In addition to providing a measure of the size and

shape of the earth, the satellite triangulation also provides orientation

of the continental network in the 48 conterminous states and a direct

measurement and orientation to Alaska and Hawaii. Figure 5 shows a diagram of the Worldwide Satellite Triangulation Network which was com- pleted in 1971.

Figure 5 Worldwide geometric satellite network

91
Additional satellite triangulation locations have been determined to provide direct measurements over continental North America and adjacent

locations to frame the North American Datum within the worldwide network.

These locations are shown in Figure 6.

Figure 6 Sotellilite triangulation in North America

92
A. Adjustment of the Framework

The adjustment involves dividing the United States into regions and

framing the North American Datum on the surface of the continent.

The partitioning and framing of the NAD is accomplished by means

of precise transcontinental traverses which separate the Nation

into ten regions. Geoceiver (Doppler) measurements reinforce the

traverses in framing the datum for a new adjustment. The precise

traverses and the geoceiver measurement locations are depicted in

Figure 7

Figure 7 Triangulation , traverses, doppler and satellite trianeulation stations

in the United States in 1973

More than 10,000 miles of 13,000 miles of traverse depicted have been

completed as have 40 of the 140 geoceiver locations.

93
B. Mathematical Adjustement of the Framework

The adjustment of the framework is simply the mathematical process

of manipulating the geoceiver, precise traverse, and satellite triangulation measurements in such a way that divergences in the various

measurements are optimally distributed. The framework is fitted

to the shape of the earth in the same process. Preliminary studies

and evaluation are now in progress using the measurements that have

been completed to date.

C. Data Conversion to Automated Format

It will be necessary to convert all the pertinent information of the

horizontal control network to a single automated computer format to facilitate a new general adjustment. The kinds of information pertinent to a new adjustment which must be converted to a single format

for computer processing include the survey measurements of record,

lists of directions, lists of locations, and descriptive information

for the more than 125,000 monumented points in the network at this

time.

The initial steps to convert the data are in progress. Computer

programs are being prepared and key punching of basic information

is underway. Other forms of data are being assimilated for the

conversion.

D. New Measures for the Adjustment

The new surveys required to facilitate a new adjustment of the

network are essentially distance and direction measurements. The

measurements will provide direct connections between key parts of

the network and new baselines and azimuths in known weak areas,

as illustrated in Figure 8.

The new measurements will involve approximately 600 baselines and

azimuths and 5300 miles of new surveys in the 8 regions of the

conterminous United States. New measurements are being made in

Regions 1 and 2 to accommodate the scheduling priorities set forth

later in the study.

94

E. Adjustment for a New North American Datum

The actual mathematical adjustment will involve a number of steps

summarized briefly as:

1. Computer analysis of network surveys

2. Computation of sections of the network within a region

3. Preliminary adjustment of the network by region

4. Final mathematical adjustment of network in each

region

5. Assimilation of final data and publication of the new North American Datum.

Computer analysis of network surveys in Region 1 have been initiated.

Survey and Development Engineering Dependent on the

North American Datum.

96
V. OPERATIONS PLAN

The tasks outlined in the preceding sections must be accomplished

systematically and undertaken in a coordinated manner to accommodat

sequential integration as the work proceeds. The operational plan

which follows is recommended for implementation, and provides for:

a. Completion of a general adjustment and new North

American Datum by 1980.

b. Publication of the new datum for all conterminous

states by 1980.

c. Maximum and efficient utilization of base program

resources and facilities.

d. The beginning of benefits returned to the public

by July, 1978.

Light wave distance measuring on the Precise Traverses in the

Framework.

97
The plan to achieve a new adjustment of the North American Datum is

relatively straightforward. The tasks to be performed have been

sequentially scheduled and milestones to mark significant events have

been established. Table 2 shows the schedule of milestones to be

completed during the five-year (1975-1979) period and the regions in

the Table are outlined on the accompanying diagram of the United States.

TABLE 2. OPERATIONS SCHEDULE-NEW ADJUSTMENT NORTH AMERICAN DATUM

FISCAL YEAR

1975 1976 19 77 1979 19«0

Perform field surveys forming a framework for updating the North

American Datum.

Doppler & TCT. Regions 1-4Doppler and TCT

Regions 5-8

Framework completed,

Jan. 1977.

Perform an adjustment of the framework for updating the North American DatumAnalyze Framework Data

Regions 1-8

Adjust Framework

.

Perform the new measurements re- quired and final adjustment

of the network in Regions 1 & 2 of the 10 Regions of the country

Azimuth and Distance Measurements and Network Analysis. Regions 1 & 2. Adjustment

Completed.

Convert all survey measurements

and listings to automated computer format.

Regions 1 &2 Regions 3 &4 Framework

and Regions

5 and 6.

Regions

7 and 8 Final Re- vision Co Format.

Perform the new measurements re- quired, final adjustments for Regions 3 - 8, — the finish of the new adjustments in the 48 conterminous States.New Azimuth and Distance Measurements and Network

Analysis. Regions 3-8.

Final Ad- justment

Regions 3-8

Publish

North American

Datum

Initiate the area Adjustments in Regions 9 & 10 (Alaska and

Hawaii). Distribution of the new North American Datum.

Framework and Data

Conversion. Regions

9 and 10.

98
The first main milestone will be reached in FY 1977 upon completion of

the remaining 4500 kilometers of precise transcontinental traverses and

100 Doppler (Geoceiver) measurements which form the framework for updating the North American Datum, This framework will be fitted to the

Worldwide Satellite Triangulation Network and thereby relate North America

to other continents as well as to the shape of the earth. In addition,

the traverses will provide the framework with a uniform standard of

accuracy in all regions of the country. The Doppler measurements will

reinforce the precise traverses and extend uniform accuracy into the

interior of the regions.

The second milestone involves combining the Doppler, precise traverses,

and satellite triangulation measurements into cohesive mathematical

relationships, resulting in a mathematical adjustment of the framework

for the new datum. It will be accomplished in 1977, immediately after

all measurements for the framework are completed.

Milestone 3 will be reached when final adjustment is completed for

Regions 1 and 2 in 1978. This means that all survey listings will have

been converted to computer format, the network surveys analyzed, and new measurements to correct discrepancies and strengthen weak areas finished

prior to the final adjustment which will provide cohesive mathematical

relationships between all network control points in Regions 1 and 2.

Milestone 4 marks the finish of the conversion of the North American

Datxim records to automated computer format so that the listings of geographic positions, survey measurements and descriptive information for

all 48 conterminous states will be accessible by computer for final

adjustment of remaining Regions 3-8. The conversion of data is a major task which must be carefully coordinated in the earlier stages to facilitate the adjustment of the framework, analysis of survey network

and systematic final adjvistment beginning with Regions 1 and 2.

Milestone 5 marks the completion in 1979 of the new horizontal control

network adjustment in the 48 conterminous states. It means that after

all data have been converted in format, the network surveys analyzed,

and required new measurements made, the final adjustment makes an updated

North American Datum a reality, after approximately 50 years since the

1927 adjustment.

99
100
VI. RESOURCE REQUIREMENTS/SCHEDULE

Tne operations schedule covers a six-year period, extending one year

beyond the five years required to complete the new datum for the 48

conterminous states. Implementation of the tasks, which are outlined

will require resources in excess of those which are available from base

program funding during the course of the project.

Resources required to produce the new NAD will total $15.7 million during

the five-year course of the project. Of this amount, $8.2 million will

be made available from base program funding and additional new funding

amounting to $7.5 million ($1.5 million in each of the years), will be

required.

Resource requirements for the sixth year (FY 1980) to extend new NAD

adjustment operations into Alaska, Hawaii and our Caribbean Islands

(Regions 9 and 10) amount to $0.2 million.

Table 3 lists the total resource requirements and the application of

base program and new funds which will be applied toward completion of

the milestones in the operations schedule.

TABLE 3. SCUEDCLE OF RESOCTBCE REQUIREMENTS

FUNDING IN $ (Thousands) MILESTONES FY 75 . FY 76 . FY 77 . FI 78

j n 79 . FY 80

PERFORM FIELD SURVEYS FORMING A FRAMEWORK FOR

DPDAIISG THE SORrH AMERICAN DATUM. 426

(497)*

765 576

PERFORM AN ADJUSTMENT OF THE FRAMTrfORK FOR UPDATING THE NORTH AMERICAN DATUM.

133

( 26)* 141 108

PERFORM THE NET.' MEASUREMENTS REQUIRED AND

FINAL ADJUSTMENT OF THE SZT-ORK E." REGIONS

1 AMD 2 OF THE 10 REGIONS OF THE COUNTRY.

470

(488)*

1130 329 155

CXWVERI ALL SURVEY MEASUREMENTS AND LISTINGS

TO AUTO.MATED COMPUTER FORMAT.

327 (180)*507 497 42a 243

PERFORM THE Nt- MEASUREMENTS REQUIRED, FINAL ADJUSTMENTS FOR REGIONS 3-8, — THE FINISH OF THE NEW ADJUSTMENTS IN THE 48 CCNTERMDJOUS

STATES.

368

(309)*

677 1711 2816 2485

ISITIAIE THE AREA ADJUSTICNTS IS REGIONS 9 AND

10 (ALASKA AND HAWAII) . DISIRIBOTION OF

THE NEW NORTH .«ERICAN DATUM.

91 140

BASE PROGRAM FUNDS TOTAL

SEW FUNDS* TOTAL GRAND TOTAL

1724

(1500) 3224

3220

3220

3161

3161

3399

3399

2819

2819

140

140

101
The project will involve 564 man-years of effort over the five-year

period as shown in Table 4. Four new positions will be required to initiate the acceleration of effort with new FY 1975 funds. The

remaining personnel requirements will come from base Geodetic Surveys

and Services programs. Contract efforts will be used to the maximum

extent possible for the new surveys and data conversion for machine

processing.

TABLE 4.

PERSONNEL REQUIREMENTS FOR NEW ADJUSTMENT

(MAN-YEARS OF EFFORT)

FY 75 FY 76 FY 77 FY 78 FY. 79 TOTAL

98 108 118 136 104 564

102
APPENDIX H. THE ANSI OPTIMUM

METRIC FASTENER COMMITTEE

The ANSI Special Committee to Study Development of an Optimum Metric Fastener System

was appointed by the American National Standards Institute in April, 1971. Briefly

stated, its purpose and objectives are: Develop a system of mechanical fasteners,

to be stated in metric units of measure:

(1) To incorporate into the design of each

fastener technical refinements contributing

to improvement in performance capability.

Object -- cost reduction through technical improvement.

(2) To simplify to the absolute degree possible the number of items recognized as standard in the system.

Object -- cost reduction through simplification.

More specifically, the committee is developing a total system of mechanical fasteners

with dimensions and properties stated in metric units. In its work, it is exploring all

opportunities to improve the design of each

fastener in every way which will enhance its

performance capability. It is limiting to the fewest possible, the number of different

sizes, series, types and styles, and grades

of fasteners to be recognized as standard.

The new system will take full advantage of

all new ideas, and modifications in product

design. It will be as non-disruptive of

existing metric practice as possible.

Target completion date for basics of the

system is the spring of 1974.

Scope - The scope of the OMFS study extends

to the entire n anical fastener field

with priority given to threaded fasteners

and associated specifications such as screw

threads, material and performance, quality assurance and product design.

NBS has participated in this study through

one of its staff who is a member of this com- mittee. At their request, NBS has gaged several hundred screws and nuts, of various

sizes, selected randomly from several screw manufacturers to determine if the thread

elements of these samples were within the

limits specified by Handbook H28, ScrewThread Standards for Federal Services. The

data from this sampling will be used by the

Committee to determine the thread tolerances

for the proposed Optimum Metric Screw Thread

System.

Organization and Membership - Committee re- lationshios to the USA, Canadian, and international standards groups are shown in fig- ure 1. The chart shows the relationships

between the worldwide organization (International Organization for Standardization-ISO)

INTERNATIONAL ORGANIZATION FOR STANDARDIZATION (ISO)

TECHNICAL COMMITTEE I SCREf THRCAOS ICHAlR- SWEOEHI ITECHNICAL COMMITTEE" 2

eOlIS.KUIS AND ACCESSORitS ICHAlR CERMANT)

JAPAN NETHERLANDS GERMANY

UNITED

KINGDOM USA

AMERICAN NATIONAL STANDARDS INSTITUTE

ANSI B-l

COamTTEE ON SCREI THREADS

I

ANSI B-ie

COMHIITEE Ok EASIENEK OmEHSIOKAE STOS 1

"

SAE FASTENER

COMMITTEE

SAE OIV 29

NECHAHICAI. t CHEMICAL

REO'HEIilS FOR FASIEKERS

l_| ASTH SUBC AI22

"l"

1 SECIIO* ON eOLlINC

I I

J ASTM SUBC A 1 26

FASIENERS

INEER-OEPARIMENTAl scREt iHREAO :m

IJ S COVERNMENII .1-

INOUSTSIAL FASIENERS

INSTIIUIE TECHNICAL COMM

CANADA FRANCE SWEDEN SWITZERLAND OTHERS

CANADIAN STANDARDS ASSOCIATION

ANSI SPECIAL COMMITTEE TO STUDY DEVELOPMENT

OF AN OPTIMUM FASTENER SYSTEM

Figure H-1. Committee relationships.

103
with its two major technical committees (screw

threads and fasteners) and the standing com- mittees affiliated with American National Standards Institute. The ANSI Special Study Committee was created as an agency serving all of

these USA committees to avoid duplication of effort and to assure a prompt and thorough study.

Because of the mutual interests of USA and

Canada, this special committee is maintaining

liaison with the Canadian Standards Association, as well as ANSI. Several special subcommittees have been created within the Committee to define, more specifically, the task,

recommend priorities, and to conduct the ex- tensive technical investigations.

Committee membership is limited to assure

that the effort does not become cumbersome,

but, at the same time, assure that adequate

expertise representing all disciplines is

available. Approximately 40 percent of the

members represent users of fasteners, 40 percent represent producers, and the remainder

represent U.S. government, Canada, aerospace,

and overseas interests as shown below:

Member Affiliation Summary

User-Industrial, Auto & Agricultural 11 Government 2 Manufacturer - U.S. 8

- Canada 2 Total Members 23

Technical Consultants, Aerospace,

and Europe , 5 Total 28

A membership roster and how the OMFS is organized into six subcommittees is shown in figures 2 and 3.

ANSI SPECIAL COMMITTEE TO STUDY DEVELOPrtNT

OF AN OPTIMUM METRIC FASTENER SYSTEM EXECUTIVE

S. E. Mallen

Chm.

COMMITTEE

- MEMBERSHIP ROSTER -

Stanley E. Mallen, Chm., Ford Motor Co. Arthur R. Breed, Vice Chm., The Lamson & Sessions Company

John J. Artman, Department of Defense

John W. Axness, Deere & Company

Donald N. Badgley, Clark Equipment Company

Thomas C. Baumgartner, Standard Pressed

Steel Company

Richard B. Belford, Industrial Fasteners

Institute

Geoffrey Dreger, P. L. Robertson Manufacturing Company, Ltd.

H. William Ellison, General Motors Corp.

Norman B. Johnston, Intl. Harvester Co. Rudy C. Kozlik, National Lock Fasteners,

Div. of Keystone Consolidated Ind.

Frank V. Kupchak, Westinghouse Electric Corp.

Jack B. Levy, General Electric Company

Arthur R. Machell, Xerox Corporation

John C. McMurray, Russell, Burdsall & Ward Bolt and Nut Company

Herman G. Muenchinger, Continental Screw Co. Joseph S. Orlando, ITT Harper Inc. Ian M. Park, The Steel Co. of Canada, Ltd.

Jack Shugart, Rockford Products Corporation

Arthur G. Strang, Natl. Bureau of Standards

Louis R. Strang, Caterpillar Tractor Co. William M. Thatcher, US Steel Corporation

David W. Vial , Chrysler Corporation

C.J. Wilson, (Secy), Ind. Fasteners Inst. European Liaison Representative

Peter J. Gill, GKN Screws & Fasteners Ltd.

Technical Consultants

Robert M. Byrne, U. S. Screw Bureau

Ernest J. Heldmann, Holo-Krome Company

Aerospace Technical Consultants

Lloyd W. Justice, General Electric Company

B. H. Beal , Grumman Aerospace Corporation

Corresponding Liaison for Australia

J. R. Paton, Standards Assoc. of Australia

SCREW THREADS

Baumgartner

Chm.

MATERIALS

S PERFORMANCE

A. R. Dreed

Chm.

PRODUCT DESIGN

W. Ellison

Chm.

INSPECTION

AND QUALITY ASSURANCE

I. M. Park

Chm.

SMALL PRODUCTS

R. Machcll

Chm.

EDITORIAL AND

PUBLIC RELATIONS

R. B. Belford

Chm

Figure H-2. The six subcommittees of the

organization Optimum Metric Fastener System.

Figure H-3. ANSI Special Committee to study

development of an optimum metric fastener

system.

INTERNATIONAL PROCEEDINGS

Background - The ultimate objective of the

ANSI Special Committee is to design a metric

fastener system sufficiently attractive technically and economically that it will become

the single internationally accepted system

of mechanical fasteners. Very early the Com- mittee recognized that success in achieving

104
this goal depended largely on establishing

a close and continuing liaison with fastener

producing and using industries in other

principal industrialized countries of the

world. The Committee fully appreciated

that all recommendations and proposals

originating from its studies would even- tually have to be channeled through ISO procedures. Consequently, one of its first

efforts was to arrange a working two-way

information exchange.

ISO - the International Organization for

Standardization - is a federation of the national standards bodies of the countries of

the world. The responsibility for development and issuance of international standards

is assigned to Technical Committees. Technical Committee 1 (TCI) on Screw Threads and

Technical Committee 2 (TC2) on Fasteners are

the two Committees sharing responsibility

for standards relating to threaded fasteners.

Both Committees have functioned for over 20

years, both have accomplished a great deal,

and both are still extremely active with the

pace of accomplishment, particularly TC2, ac- celerating dramatically during the past five

years

Official contact between the ANSI Special

Conmiittee and ISO was not possible until

such time as specific proposals were ready

for submittal to TCI or TC2. However, "un- official" contact was not only desirable

but viewed as mandatory by the ANSI Special Committee.

Immediately after its appointment in

April 1971, the Committee made its first

international overtures. In May, six of

its members visited with industry representatives in Sweden (the Secretariat of

TCI), France, Germany (the Secretariat of

TC2), and England. The purpose of these

four meetings was to describe the new ac- tivity, to explain why this program of

study was being undertaken, to suggest the

potential benefits which could be shared

by all countries of the world, and to

invite participation and technical input from all interested sources. In July,

two fastener experts from England met in the USA with several of the Committee members to gain a fuller understanding of the

Committee's intentions and plans. Shortly

after their return to Europe, a request

was received and quickly accepted that a European Liaison be appointed to membership on the ANSI Special Committee.

In May 1972, the Committee, again represented by a six-man delegation, presented

an in-depth report in London, England describing progress of its first year of study.

In January 1973, it was apparent that

studies on screw threads, diameter-pitch

series, and strength grades for ferrous

fasteners would be finalized within a few

weeks and that it was now an appropriate

time to formalize contact between the Committee and the ISO Technical Committees.

However, before submitting specific and

detailed proposals, the Committee felt it

would best serve all interests if some preliminary discussions could be arranged to informally explore the possibility of

merging OMFS proposals into existing and

planned ISO standards.

In early February, one of the Committee

members met with representatives from

Germany, Sweden and England to plan the

most suitable means for bringing the principal ISO interests together for an ex- ploratory discussion of OMFS proposals.

Shortly after this meeting, the Chairman

of TCI and TC2 jointly announced appointment of an IS0/TC1/TC2 Ad Hoc Advisory

Panel and extended invitations to 29 fastener experts from 14 countries to serve

as members. A first meeting of the Panel was scheduled for May 28-30 in Frankfurt,

Germany with the main agenda item being

discussion of OMFS proposals. This Engineering Report was then prepared by the

Committee and sent to all members of the

Ad Hoc Advisory Panel in late April.

Ad Hoc Advisory Panel Meeting - Attending

the Frankfurt meeting were 38 representatives from 12 countries - Austria, Canada,

France, Germany, Hungary, Italy, Japan,

Netherlands, Sweden, Switzerland, United

Kingdom and USA. The ANSI Special Committee was represented by nine of its

members. The only members of the Panel

not attending were those from Russia and

Czechoslovakia; however, the latter com- municated their comments through the

Hungarian member. It was fully understood that commitments were neither being

sought nor would any be given. The prime

objective was to review progress of the

OMFS studies and comment on the possibility of ISO acceptance of OMFS proposals

already completed and predictable recom- mendations which might originate from

other areas of study still underway. A report of the Panel's views follows:

Screw Threads - The Panel accepted the

OMFS statistical evaluation which proves

the improbability of interference occurring when internally threaded fasteners

having ISO metric screw threads are mated

with externally threaded fasteners having

OMFS threads. There was no fear that

mated fasteners with the two thread systems would not function safely and without

noticeable strength-of-connection difference. The Panel expressed no criticism

of the OMFS contention that a more generous radiusing of external thread roots

105
enhances a fastener's fatigue resistant

properti es

.

There were no technical criticisms of

the OMFS recommended profile, however, the

majority of the Panel opposed any change

to the ISO basic thread profile - the reason offered was a general reluctance to change from a profile adopted by ISO in 1958, one which has necessitated major

manufacturing change by most metric countries and one which has so far proven

satisfactory. The Panel appreciated that

the principal reason for the reduced thread

height of the OMFS basic thread profile was

to accommodate a larger root radius on the

external thread. It pointed out the possibility of achieving an increase in root

radius without an accompanying change to the ISO basic profile by adjusting minor

diameter tolerances. The Panel urged the

ANSI Special Committee to consider this

possibility, accept the ISO profile and

then work cooperatively with other countries in TCI to achieve the desired larger

root radiusing of external threads.

There was little discussion of the OMFS

proposals to define thread limits of size

using the boundary method and also using

basic major diameter rather than pitch

diameter as the dimensioning reference

datum. The Panel noted the simplicity of

this concept and anticipated no problem affecting interchangeabil ity of product if it

is used.

The Panel was extremely complimentary

of the new gaging system. It viewed the

double NO-GO gaging concept as a significant technical advance and predicted favorable consideration by TCI. It was suggested the technique might be best suited

for acceptance gaging of only those products intended for high-fatigue service

because of a suspected higher gaging cost.

In reply, the OMFS representatives reported

work is underway to evaluate gage wear, gaging time, and other expense items oc- curring during routine production and re- ceiving inspection. They expressed an opinion that results would be favorable

and that in North America, the new gaging

practice would not be limited in its appl ication.

The Panel expressed concern with the

OMFS proposal to reduce screw thread tol- erances and allowances from those now specified for the current ISO grade 6g/5H.

It urged the ANSI Special Committee to reconsider and hopefully accept the ISO

tolerancing system.

In summary, the Panel was generally

complimentary of the proposed OMFS screw

thread system. It agreed there should be

little, if any, problems in mismatching

of fasteners if the OMFS system was introduced as proposed and the ISO system

was continued without revision. It asked,

however, that the ANSI Special Committee

review its recommendations with respect

to the basic thread profile and to toler- ances and allowances and learn if some modifications could be accepted to bring

the two systems into conformance.

Diameter-Pitch Series - It is interesting

to note that of the 25 diameter-pitch combinations, 20 are ISO standards. The five com- binations that deviate were proposed for two separate reasons: (1) The Committee was genuinely concerned that the fineness of ISO

thread pitches for the 3, 3.5, 4 and 5mm

sizes could cause installation problems

during high-speed driving on fast-moving

assembly lines. Such troubles have been ex- perienced when using fine thread fasteners

in sizes No. 4 thru No. 8, and the Committee was fearful of a reoccurrence particularly as ISO metric coarse pitches in these

sizes are as fine or finer than inch series

fine threads, and (2) The Committee's proposal that a new size, 6.3mm, be introduced

was warranted by the favorable results of

both technical and economic studies.

The Ad Hoc Panel was very much opposed

to recommending ISO recognition of the OMFS

slightly coarser pitches for the 3, 3.5, 4,

and 5mm sizes. The principal concern was

the chance of mixing and mismatching fasteners having OMFS pitches with those

having ISO. Several members of the Panel

disputed that problems would occur during

high-speed assembly and stated their own industries' experiences have been entirely

satisfactory. On this basis, the OMFS representatives offered to recommend to the

ANSI Special Committee that the ISO coarse

pitches for these four sizes be provisionally accepted and that actual assembly

line testing be conducted to verify that

the ISO pitches would be suitable. If

such research indicated that a legitimate problem existed, then the ANSI Special Committee would return to the Panel

with the technical evidence to support

the need for a coarser series of thread

pitches for the four sizes 3 thru 5mm.

There was general agreement by the

Panel that the economics favored a single

intermediate size between the sizes 5 and

8mm. Optimism was expressed that TCI

would act favorably in giving ISO recognition to such a new diameter-pitch com- bination. The OMFS simulation studies

showed the economics strongly support

the 5.3 X 1 size.

The ANSI Special Committee has still

much work to do. However, the principal

features influencing interchangeabil ity

106
between systems - screw threads, diameter

pitch series, strength grade properties - are not reasonably finalized and have been

explored internationally. Based on the co- operative spirit evidenced at the Frankfurt

meeting, it now appears that a single internationally acceptable system of fasteners

can become a real ity.
REFERENCES

[1] 43rd Australian-New Zealand Association

for Advancement of Science Congress,

1971.

[2] Quality Management & Engineering,

July, 1973.

[3] Correspondence with Mr. J. C. McKinney

Chief of the Army Standards Lab.

[4] Hughes Research Laboratories, Malibu,

Cal ifornia

[5] NBS Technical News Bulletin,

March 1967, p. 43.

BIBLIOGRAPHY

Publ ications

Standard & Poor's Corporation Reg. 1974.

Standard & Poor's Yellow Sheets.

Value Line Investment Survey, 1974.

Moody's Handbook of Common Stocks, 1973.

Annual Survey of Manufacturers 1970-1971 , US Dept. of Commerce, Bureau of Census.

US Industrial Outlook, 1974, US Dept. of

Commerce

.

NBS SP329, An Index of U.S. Voluntary

Engineering Standards.

U.S. Department of Defense, Index of

Specifications and Standards, May, 1973.

General Services Administration, Index of

Federal Specifications and Standards,

(FPMR 101-29.1), Jan. 1, 1973.

NBS SP375, An Index of State Specifications and Standards.

Specifications and Tests of Metal Cutting

Machine Tools, University of Manchester

Institute of Science and Technology,

Machine Tool Engineering Division,

April 30, 1970.

Lane, Donald L., Method for Evaluation

and Certification of the Moore No. 3 Universal Measuring Machine, Re- port UCRL 50679, Lawrence Radiation

Laboratory, June 1969.

Census of Manufacturers, US Dept. of Commerce, Bureau of the Census, 1967, 1963.

US Dept. of Commerce, social and Economic

Statistics Administration, Bureau of

the Census, Preliminary Reports, 1972

Census of Manufacturers, Industry Series, MC72(P)-35C-4, Machine Tool Accessories, SIC 3545, issued March 1974.

US Dept. of Commerce, Bureau of the Census, Annual Survey of Manufacturers,

1971, M71(AS)-2.

Predicasts, April 27, 1973.

Selected Electronic and Associated Products, Series MA-36N(71)-1 , 1971,

US Dept. of Commerce

Mechanical Engineering and Management,

(trade journal), August 1972.

Iron Age (trade journal), Oct. 25, 1973.

American Machinist, (trade journal),

Oct. 15, 1973.

Bendix Technical Journal, (trade journal),

Summer/Autumn 1972.

Laser Focus, (trade journal), Jan. 1973,

Oct. 1973.

Optical Spectra, (trade journal). May 1973.

Hewlett-Packard Journal, August 1970.

North American Datum, report from National

Academy of Sciences and National Academy

of Engineering.

American Machinist, (trade journal published by McGraw-Hill), Oct. 29, 1973.

Petroleum Facts and Figures, American

Petroleum Institute, 1971.

NBS Handbook H28, Screw Thread Standards

for Federal Services.

108
U.S. DEPT. OF COMM. BIBLIOGRAPHIC DATA

SHEET

1. PUBLIC Al ION OR REPORT NO. NBSIR 75-926

2. Gov't Accession

No.

3. Recipient's Accession No.

4. TITLE ASD SUBTITLE

THE NATIONAL MEASUREMENT SYSTEM FOR LENGTH AND RELATED

DIMENSIONAL MEASUREMENTS, PART I

5. Publication Date August 1976

6, Performing Organization Code

7. AUTHOR'S) J n 1 D u J. W. Lazar and R. L. Bach

8. Performing Organ. Report No.

9. PERFORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

UcrAKTMcNl Ur t^OMMtKL.t

WASHINGTON, D.C. 20234

10. Project/Task/Work Unit No.

11. Contract/Grant No.

12. Sponsoring Organization Name and Complete Address (Street, City, State, ZIP) 13. Type of Report & Period Covered

14. Sponsoring Agency Code

15. SUPPLEMENTARY NO! ES

16. AB-STR.ACT (A 2 00- word or less lactuat summary ot most si^ilicant mlormation. It document includes a signiiicant

bibliography or literature survey, mention it here.)

The determination of length and related dimensional measurements con- stitute the largest group of measurements made in science, manufacturing

and technology. We have shown that length and related dimensional mea- surements have impact upon many areas of the economy. We have also shown

that the National Measurement System is viable and is adaptable in con- forming to the changing requirements of industry. The greater accuracy

requirements of some industries brought new measurement techniques into

use, e.g. the fringe counting laser interferometer systems now used in

many tool rooms and metrology laboratories. We have found no deficiencies in the system but only in individuals or the measurement technique

that they use as shown in the comparison measurement on audit packages

that were made by the various standards laboratories.

17. KEY UORDS (six to twelve entries: alphabetical order; capitalize only the first letter of the first key word unless a proper name; separated by semicolons)

Dimensional; gage; instrument; laser; length; machine; measurements;

standard

18. AVAILABILITY [_J Unlimited

IXJ For.Official Distribution. Do Not Release to NTIS

1 ) Order From Sup. of Doc, U.S. Government Printing Office Washineton. D.C. 20402. SD Cat. No. Cn

i 1 Order From National Technical Information Service (NTIS)

Springfield, Virginia 22151

19. SECURITY CLASS

(THIS REPORT)

UNCLASSIFIED

21. NO. OF PAGES

20. SECURITY CLASS

(THIS PAGE)

UNCLASSIFIED

22, Price

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aU.S. GOVERNMENT PRINTING OFFICE: 1976 210-801/377 1-3