NBSIR 74-451

Field Comparisons of Steel

Surveyors' Tapes

C. Leon Carroll, Jr.

Institute for Basic Standards

National Bureau of Standards

Washington, D. C. 20234

November 1973

F mal

z

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

NBSIR 74-451

FIELD COMPARISONS OF STEEL

SURVEYORS' TAPES

C. Leon Carroll, Jr.

Institute for Basic Standards

National Bureau of Standards

Washington, D. C. 20234

November 1973

Final

U. S. DEPARTMENT OF COMMERCE. Frederick B. Dent. Secretary

NATIONAL BUREAU OF STANDARDS. Richard W. Roberts. Director

Field Comparisons of Steel Surveyors' Tapes

C. Leon Carroll, Jr.

The accuracy of a surveyor's measurement must often be provable to

100 ppm (sometimes in a court of law) and a significant feature of

such proof is his knowledge of his tape length under specified conditions. This paper describes a technique which will provide such

knowledge. The technique is an easily performed comparison between

his tape and a calibrated standard tape (perhaps borrowed from a State Weights and Measures Laboratory) . This scheme has been tried

out at the National Bureau of Standards under a number of

conditions likely to be encountered in the field, and the results

of these tests did not differ significantly from a comparison in

our tape laboratory conducted under ideal conditions and using

state-of-the-art apparatus. Traceability to NBS is established by

the calibration genealogy of the standard tape.

A calibration activity measures and certifies the actual length of

the standard tape at 68°F under ten pounds tension. Given access

to such a standard tape, the surveyor may determine the actual

length of his own tape. Although his experiment will not

necessarily be conducted at 68°F, his data will reflect length at

68°F to an accuracy appropriate to 100 ppm survey work if his tape

and the standard tape have similar thermal, elastic and geometric

properties. These required conditions exclude a comparison between

a steel and an invar tape because of grossly different thermal properties. The surface finishes of the tapes should be similar if

the comparison is made in the direct sunlight.

The comparison experiment, shown schematically by the sketch on the

specimen data sheet, figure 1, consists of measuring the difference

in lengths between the standard and test tapes. If the certified

length of the standard tape is S, and A, B, C and D the measurements indicated on the sketch, then the length of the test tape, L,

at 68°F under the tension applied during the comparison is given by

L = S + [A - B - C + D]K

where K is the coefficient relating the units of the small end

scales to the tape units (1 Foot = 304.8 millimeters).

The details of the experimental setup are shown in figures 3 and 4.

No effort should be made to align the ends of the two tapes to coincidence. However, keep the tapes as close to the end scales as possible to reduce reading errors due to parallax. Graph paper
placed directly under the tapes is superior. Experience has shown

that residual errors associated with failure to achieve perfect co- incidence are larger than those associated with measurements of

lack of coincidence. Millimeter graduations on the small end

scales are far more practical than any other commonly used

graduation interval (e.g. 64ths or lOths of an inch). This is

because the normal eye can estimate to 1/10 of a millimeter with an

assurance of about 0.15 millimeter using a low-power handheld

magnifier. The errors injected into the overall comparison

experiment by the imperfections in inexpensive millimeter scales

are insignificant in this experiment. The end scale requirements

are:

(1) That the graduations of the two edges of the small

scale start at a common "zero."

(2) That the small end scales will be required to measure

a distance of no more than about an inch by insuring

that the end point graduations on the two tapes are separated by no more than about an inch along their

lengths

.

(3) For convenience of observation (estimating 1/10 mm)

the thickness of the graduation lines be no more than

about 1/10 the graduation interval. Good quality

graph paper satisfies this requirement adequately.

Survey measurements to 100 ppm allow for errors of 0.12 inch per

hundred feet. Although it is unlikely that errors of as much as one-third of this allowance could occur in the comparison experiment, good practice demands a redundancy of measurements. The

specimen data sheet (figure 1) requires three independent measurements of the difference between the two tape lengths. Requirements

are satisfied by moving both end scales after a round of observations on A, B, C and D.

If the surveyor customarily makes only one field measurement of a

distance (for example, from a bench mark to a fence), then the com- parison experiment is adequately performed by filling out and

calculating one data sheet (i.e. three determinations). On the

other hand, if his customary practice is to make the measurement

twice and report the average value, then he should fill out two

data sheets and use the average of the two values of L obtained

thereby

.

As pointed out above, the certified value, S, of the standard tape

refers to its length at 68°F and ten pounds tension. The

similarity between the thermal properties (that is, the temperature

- 2 -
coefficients of expansion of the two tapes) eliminates the

requirement to conduct the experiment at 68°F. The tension applied

to the two tapes, however, must be carefully measured. The tension

in the standard tape must be ten pounds inasmuch as this is the

certification tension. Our experimental setup is shown in figures

3 and 4. It is noted that we also used a spring balance (checked

as shown in figure 2) to tension our test tape to the ten pound

level, however, this is not required. The comparison experiment is

perfectly valid regardless of the tension, Q, applied to the test

tape. The surveyor may apply any amount by any tensioning device

of his choice. Inasmuch as the value of L (calculated above) is

valid only at tension Q, the surveyor will normally stretch his

tape to a tension of Q during practical field measurements.

There are times at which the surveyor will prefer to stretch his

tape to the "tension of accuracy," Q^. This is the amount of tension which causes his tape to assume a length of "exactly" 100 feet

at the tape temperature during the field measurement. at tape

temperature T may be calculated from an algebraic combination of Q

and L (as determined in the comparison test) with a and AE (two of

the constants associated with the tape and obtainable from the

manufacturer)

QA

= Q + AE[1 - O.Ol(L) - a(T-68)]

where a is the temperature coefficient of expansion of the tape in

feet per foot per degree F, and AE is the effective product in

pounds force of Young's modulus of elasticity of the tape by its cross section area.

From years of experience we have found that .000006^5 is an

adequate value for a of steel tapes. The surveyor may check the

manufacturer's estimate of the AE product by a simple extension of

the comparison experiment. From the initial experiment he has

determined that a value of L exists at a tension of Q. He must now

determine, from a second comparison, a second value of L, namely

Li , which exists when the test tape is stretched by a tension of

Qx

. The tension of the standard tape remains at ten pounds during

both comparisons. Ordinarily, Qj , should be about ten pounds

greater than Q. From Q, Qj , L and Lx he may calculate AE.

For example, suppose the surveyor has found that at Q=10 pounds,

L=99 • 9984 feet. This is illustrated in figure 5 showing an actual

NBS comparison experiment conducted on an asphalt driveway. If a second comparison (conducted at Q1 =20 pounds) yielded a value of

1^=100.006, then

(Q 1 - Q)100

AE = —y,—I~l

= 1-32,000 pounds (force)

which is in adequate with the manufacturer's estimate.

- 3 -
It should be carefully noted that T in the formula for QA

is the

temperature of the tape. If the tape is shielded from the direct

rays of the sun, the ambient air temperature may be used without

unacceptable errors in QA

. If the tape is exposed to the direct

sunlight, the actual tape temperature may be thirty or more degrees

Fahrenheit above ambient, in which case the tape temperature must

be measured by a tape thermometer (obtainable from tape

manufacturers). We have found that a mercury thermometer covered

by a surface similar to that of the tape will indicate a

temperature approximating that of the tape. Thus, black friction

tape ( for use with a black measuring tape )

, or white filament type

tape (for use with a white measuring tape) will force a mercury

thermometer to approximate the measuring tape temperature. In

direct sunlight we have found a 15°F difference in the temperature

of a black tape (hotter) and a white one (colder) with bare

stainless steel and bare brass between these two extremes. Our

measurements were made in the summer (75-85°F ambient), and these

radiant effects are probably much greater during the winter in a

cold ambient.

For tapes longer than 100 feet, each 100 foot interval may be com- pared as described above. It should be mentioned that each such

interval should be subjected to the same test tension, Q.

Figures 5 5 6, 7 and 8 show the results of comparisons between the

same two tapes under various conditions likely to be encountered in

the field. The results are tabulated on the following page, all

values referring to a ten pound tension on the test tape.

- 4 -
EXTERNAL CONDITIONS

AMBIENT

TEMP TAPE LENGTH PAW DATA

Asphalt parking lot

and driveway with a % grade in bright

sunlight. 88°F 99-998^ ft. Fig. 5

On grass alongside

brick building —

mostly shade, some

sun. 82°F 100.000

2

ft. Fig. 6

On cement platform

of truck scale and

extending through

doors to outside of

scale house on ce- ment approach. 78°F 99-998^ ft. Fig. 7

On vinyl tile hallway in basement of

Metrology Building. 720p 99.999

^

Fig> g

Comparison conducted in tape laboratory under ideal

controlled condi- Not

tions. 68°F 99-999 ft. Shown

The spread of field data is .001

Q feet, or about 20 ppm, all points

being in good agreement with the laboratory experiment.

While the completed data sheet is normally adequate, it may be required to provide further documentation. The following wording is

suggested:

"This is to certify that the tape (manufacturer, serial

number, type_)_ marked ( see below) has been tested in

accordance with the procedure outlined in NBSIR Report No.

73-^08. These tests were conducted with reference to a

standard tape owned by (owner) which was calibrated by the

National Bureau of Standards under Test Number . The length of the tape tested was found to be

feet under pounds tension at 68°F with the

tape supported throughout its length."

- 5 -
This report should be dated and signed by the surveyor (or some other designated person in the organization) . The supporting data

should be retained on file. If it is felt that tested tapes should

be marked for identification, suitable marking can be done with

etching ink commercially available.

US COMM-NBS-DC
OBSERVED DATA AND CALCULATIONS OF THE LENGTH (L) OF A STEEL SURVEYOR TAPE AT 68 °F BASED

ON A FIELD COMPARISON TO A CALIBRATED STANDARD TAPE

DATE TIME AIR TEMP SKY/WEATHER

STANDARD TAPE

0 FT

1 IN II IN 100 FT APPLY 10 POUNDS

, 1 , 1 1 ! 1 1 1 -L. J J_l 1 1 1 1 1 1 1 L i I i TENSION

i

Ml IIH|IIM|.IM!|im ""I 1 " 1 CM 1 2 3 4

BMM,,,,, ""1"" ""!"" MM |

1 III CM 1 2 3 4 MM,

1

1

1 1

| 1 1 1 |

1

1

' 1' |

1

1

|

1

1 1 |

1

1

1 RECORD TENSION

Id 001 Nl II Nl 01 Nl 1 1

J

0 AND METHOD

TEST TAPE

STANDARD TAPE

Manufacturer Serial

Temp. Coef , Exp. =0/=

WT/FT=W= LBS AE=

_FT/FT/°F

LBS

Material /Color /Finish

Certified Length at 68 °F Under a Tension of

10 pounds (S=) feet

TEST TAPE

Manufacturer Serial

Temp . Coef . Exp , =c= WT/FT=W= LBS AE=_FT/FT/°F

LBS

First Trial

Second Trial

Third Trial

Mater ial/Color/Finish_

Applied Tension

Tension Method

Observed Data (in cms)

B C

POUNDS

(A - B - C + D)*

£A= SB= SC=

L = S + .010936 [EA - SB - EC + ED] =

ED=

feet

*This is a check calculation. In the absence of gross blunders these three values would

normally differ by no more than about 0.15.

REMARKS (Show calibration genealogy of the standard tape and describe conditions surrounding

comparison)

„

FIGURE 1 OBSERVER
u

t-f cu I 0) CO •H

P. i-t 4-1 3) »4-i •H <H 0) E rH d •H X O X!

CO

a

M •H CO l-i (0 iH D. •H i-l • o U <0 i-( 1 CO 01 4J c *t CU > X o Ul CO cO —I u o 4-1 a

•H

H cO o E i-j >> a 4J CD 01 o

I—I

•a c c <j CO

u 4-1

u

iHu o CO o

CO CO •H c a) o !Z OJ

*-> 0 CO to o 14 4-1

C c Q C 4-1 iH CO 4J o 0) X\ 5*. 3 rH • • N CO H 00 c 0) (0 •H XT •H u > o l-l U 4-1 0) CO •H c o CO o • 3 C •g CO c X QJ a • tn iH rH XI iH o ai o 4-1 CO CO co •H 4J 00 43 01 *j J3 >\ o c *o X

to

a i-> •a e •H 00

u 4-1 Q) rH 0) jr c CO

hi a)

u •a 4-J to 1-1 o > efl 0> CO •H u .o >

QJ o 4J 60 (0 y-i c~ o u c cu w a> X> d CO r-i CD t-i X CO CO O X X a> 4J rH c < CO • x\ X

CC & J= rH iH

O 4J U-J CJ

X o u CD tH z 0 c C •H • CO C •w

CO 0)O > CO o "a c X l-i CO c sr H 0) O 0) oc i) U cfl CO E o (0 to c rH c E •H 3 •H 0) -a o o c 4J 4-1 u 4J u o •a » CO 4J 3

0) CO «H i-i 4-1 •HO

X o a o O 4J

X

H cu c c 4.) CO CO

q:

ujo

o: o
Xo

LU <

Q.

LU

(J<

GOO

UJ>

CO

LUu cr

CD CO <

or

I-X

LU

u

CU X c

4J 3 o ox X CO o

(0 CO

<u «0 o

(0 0) C rt o o mum

•H iH h C (fl m o u c-H co o o -a o qj c u CU W T3 41

O

4-1 V-i o 3 (0 u

CO

X

01 00

i-i «H

CO 4) o 2

to

X

.u c <u X

0) 4J

r-t

CV

0! 0) D. 3

tO J-> 4J 0) X

13

Vj CO

tO CU T3 fH C tO

to o

4-1 CO CO 13

T3

C

C 0)

to iH

0) i-H o, tO

to £

4-1 CO

4J 0)

CO

X

0) 4J 4J

0) 4-> X "H H 3 • CO 4-1 0) O o a, <o

to Cu CO ^ o o 2 cu o

CO

X

4-1 (0 00 CO C C

•H i-l CO

4->

C

tj

M

O

O

C rl

a ^ s 3 fH 3

to *o

0) to ii a ^ 0 CO 60

CO 4-1

4-i a>

CO 4-1 00C M-4 •H O MX 4-: CO 13 X

CO 4J •a

CO

0>a

to

4_)

4J CO o c

.c o

CO -H

4-1 <U CO

0) 0) 0)

to

0)> rH O i-l X ft

to s x

oj cu

>-< e

tO •H «

COCO 0) O X C 4J

a) cu

•H 4J 3 >.

CO 13

01 0) a. -h

CO r-t 4J aa

<u to J3

4J

Co O COC

13 CD C 4J

0) 0) x; x U 4J

CO

CU 13

CD

4-1 4-1 tO COo

at T3

co

C 3 *H

a> co u a)

to CJc

co to c «—• H to Cu X u oo o c

CJ

u c a

to CO icu

S-i

a>

COe

cuoo

coc

•H

U-l i—I O co •H

x:

x

O to cH >>c

CU ffl cO cu> c o

*h e

-c cu

4-1

M 3 O

4J cO T3 •H 0)

4-1 CO

tO 3 3

T3

O

CO CO U i-H 00 CO

a) cu c u

CO tO

4-1 CO

tU iH

-C tu 4J >

•H

oo 3 C to

CO ,Q

cu

i-H

O CU • ^ 4J x oo a 4J c 3 U O tI X CU 4J c m jr co M i-l O -H 3 3 tO 3

4J cr a) 4-i

OBSERVED DATA AND CALCULATIONS OF THE LENGTH (L) OF A STEEL SURVEYOR TAPE AT 68 °F BASED

ON A FIELD COMPARISON TO A CALIBRATED STANDARD TAPE

DATE 7'l^"70 TIME /O AIR TEMP SKY/WEATHER

STANDARD TAPE

0 FT

1 IN II IN 100 FT APPLY 10 POUNDS

,1.1 ,1,1,1, —L,j._ J .1. J. \ ill 1 1 1

1

TENSION

ITTTTTTTI 1 1 1 1

|

1 1 1 1 unpin ,.M,|„,M CM 1 2 3 4

mi B- £— 1

1

1 1 |

1 |1 |1

id 001 Nl II Nl 01 TEST TAPE

1 CM 1

1 2

mii n in 31 1 1 11

1 1 1

1

4

IMllllll

1

1

1

1

1 I'M RECORD TENSION

Nl 1 1

J

0 AND METHOD

STANDARD TAPE

Manufacturer Serial

Temp. Coef. Exp. =o/= 0, VP OOP £ y j FT/FT/ °F

WT/FT=W= O.0/H7 LBS AE= PX^OOO LBS

Material/Color/Finish S~r£et- ff^cx- Gu-ss

Certified Length at 68 °F Under a Tension of

10 pounds (S-) /00,00 ) feet

TEST TAPE

Manufacturer Serial

Temp . Coef . Exp . =0-= O , 0 O Q QO £_£ ST^ FT/FT/ °F

WT/FT=W« Q ,Q/ tfX LBS AE= JXS^QQO LBS

Material/Color/Finish Sts-ec- /Scjc* Gccss

Applied Tension /£ POUNDS

Tension Method

Observed Data (in cms)

First Trial

Second Trial

Third Trial

A

g, //

B

// 9 1

c L22. z, n X,o2

'.97

D

/,?/.

J, 0 f

(A - B - C + D)*

- o ,o C

EA= C'37 EB= 0

L S + .010936 [EA - EB - EC + ED] =

EC= J C> 9 ED^ 1,3 T

12, 9?^ feet

*This is a check calculation. In the absence of gross blunders these three values would

normally differ by no more than about 0.15.

REMARKS (Show calibration genealogy of the standard tape and describe conditions surrounding

comparison)

.

on /\sPrt AL.-r Pa^hM*- /or a up PfiiVtrvSAy <^frM r %- &#av£T

FIGURE 5 OBSERVER C JL\ C. f
OBSERVED DATA AND CALCULATIONS OF THE LENGTH (L) OF A STEEL SURVEYOR TAPE AT 68*F BASfef

ON A FIELD COMPARISON TO A CALIBRATED STANDARD TAPE

DATE 2~llh22 TIME J AIR TEMP /X SKY/WEATHER CtCA^ (/HSt/APe*)

STANDARD TAPE

FT

I IN

I I I 1 I 1 I

It IN 100 FT APPLY 10 POUNDS

1 1 t 1,1.. TENSION

TTTTJTm- rmrrpn TTTTTTTn IMIjIMI mTTTTP CM 1 e 3 4

'!"!'"! rTTTTrm TTTTJTTTT rtTTTTTTT rTTTTTTn CM 1 2 3 4 £— 1

11 |1 |

1

| 1

1 '

1 '

1 Id 001 Nl II Nl 01

I

I

I I

I

I

I I

I

Li RECORD TENSION

AND METHOD

TEST TAPE

STANDARD TAPE TEST TAPE

Manufacturer Serial

Temp. Coef. Exp. =0/= 0>COQ00{s

l-f jT^FT/FT/ °F

WT/FT=W= 0 ; O I H

[f7 LBS AE= JZfOOO LBS

Material/Color /Finish -frggt- , lji*cK, ^oir Certified Length at 68 °F Under a Tension of

10 pounds (S») /O °< 00 / feet

Manufacturer Serial

Temp . Coef . Exp . «<yg Q , oo oo O & ^ FT/ FT/ °P

WT/FT=W« O ,0/*/ A LBS AE= /2£~~Q° ° LBS

Material/Color/Finish JVggfc

Applied Tension POUNDS

Tension Method J/>>f/</<?- JjA^AHci

Observed Data (in cms)

First Trial

Second Trial

Third Trial

A

/ 7X.

A -3 .7

B c

A£?

a*?

D (A - B - C + D)*

A g 7 - o.oz.

£A= EB= y, 3

sc= y, ^ y sd= j?.

L = S + .010936 [SA - SB - EC + ED] = feet

*This is a check calculation. In the absence of gross blunders these three values would

normally differ by no more than about 0.15.

REMARKS (Show calibration genealogy of the standard tape and describe conditions surrounding

comparison).

FIGURE 6 OBSERVER C IC . * TcX
OBSERVED DATA AND CALCULATIONS OF THE LENGTH (L) OF A STEEL SURVEYOR TAPE AT 68 *F BASED

ON A FIELD COMPARISON TO A CALIBRATED STANDARD TAPE

19a

DATE 1-1^-70 TIME °f /fl . AIR TEMP 7

$* SKY/WEATHER

STANDARD TAPE

0 FT

1 IN II IN 100 FT APPLY 10 POUNDS

.1.1 1 1 1 1 I. l..U_ .1. 1 I 1 I 1 , 1 , 1 , 1 1 1 1 TENSION

i rmpm

CM

1

1 z

rjrrrr rmjrrn

3

TTTTTTTTT- 4

B-

""I""

CM mrp

1

M M| 1 M 1 2tit 3

| MM TTTT 4

TTTT

£— i

1

' 1

1

1

1

1

1 1

1

'

1 '

1

|

I |

1 |

1 |1

I

1

001 Nl II Nl 01 Nl 1 j 1

TEST TAPE

RECORD TENSION

AND METHOD

STANDARD TAPE TEST TAPE

Manufacturer Serial Manufacturer Seria l Temp . Coef . Exp. =<y= Q OOQQOGH ^ FT/FT/ °F Temp . Coef . Exp . =a= O.COOD O h H 5^ FT/ FT/ °F

WT/FT=W= 0.0/H7 LBS AE= /X^OOQ LBS WT/FT=W°= O, O/^Z LBS AE~ /IS^OOO LBS

Material/Color/Finish S~r^eu } RlA<-K, A-djt Material/Color/Finish S:reeL , B^ao* . Q^^£L

Certified Length at 68°F Under a Tension of Applied Tension /o

10 pounds (S-) / O O > D O I feet Tension Method Sf/ftyG- Ba^A A/cr

POUNDS

Observed Data (in cms)

First Trial

Second Trial

Third Trial

A B 7<2X

c D

A 71

- B - C + D)* - 0 , o c

-o, io

SA= JTO 3 EB= V, SC= .Vg ED=

L - S + .010936 [£A - SB - EC + ED] = 9 ?, 9 Zfijj. feet

*This is a check calculation. In the absence of gross blunders these three values would

normally differ by no more than about 0.15.

REMARKS (Show calibration genealogy of the standard tape and describe conditions surrounding

comparison)

OH CeHteMT' fuA-<ro^^j op TQuvr( JCAi^T ScA^^T Af^J>

FIGURE 7 OBSERVER
OBSERVED DATA AND CALCULATIONS OF THE LENGTH (L) OF A STEEL SURVEYOR TAPE AT 68 °F BAtoif

ON A FIELD COMPARISON TO A CALIBRATED STANDARD TAPE

DATE TIME 10 '/^>7 AIR TEMP 7Z SKY/WEATHER

^

^s,per

STANDARD TAPE

A I IN II IN 100 FT APPLY 10 POUNDS

, i . 1 rl i 1 . I ,

1 1 1

1

TENSION

i

TTTTJTTrr TTTTJ,ttt 1 1 1

1

1 1 n i 1 1 1

1

1 1 1 1

1

rmTTm 1 CM 1 2 3 4 ""!"" 1 1

1 1| 1 1 1

1

1 1 1 1| 1 1 1

1

""1"" in 1

1

1 II i CM 1 2 3 4 * B

^

1

1

' 1 j 1

| 1

|

1

1

'

I

' 1

1

1

|

1

1 |

I

1

i

Id 001 Nl II Nl 01 Nl 1 0 RECORD TENSION

AND METHOD

TEST TAPE

STANDARD TAPE TEST TAPE

Manufacturer Serial Manufacturer Serial

Temp . Coef .Exp. sp's 6 , O oo o O fc- FT/FT/ °F Temp . Coef . Exp. c*y= Q<OOOOO^^S FT/FT/ °F

WT/FT=W= Q,OiH7 LBS AE= /XfOOO LBS WT/FT=W« Q-Q/4-Z. LBS AE= /XTo°t> LBS

Material/Color/Finish Stz&l Sjk±£JLf Material/Color/Finish St&stl- , 0i-Ac^« , <^aj

Certified Length at 68°F Under a Tension of

10 pounds (S-) /OP, O O ) feet

Applied Tension_

Tension Method

POUNDS

Observed Data (in cms)

First Trial

Second Trial

Third Trial

A

A

t,?7

B A£f

A

c

A^r/

A<r^

D

4£Z

(A - B - C + D)*

L = S + .010936 [SA - EB - EC + ED] =

SC= £[ ^ g £D= A- L/<r

feet

*This is a check calculation. In the absence of gross blunders these three values would

normally differ by no more than about 0.15.

REMARKS (Show calibration genealogy of the standard tape and describe conditions surrounding

comparison)

.

6^ 77^<r Fioort /a/ foAse'w&f/T'

FIGURE 8 OBSERVER CLc f%&£
NBS-1 14A (REV. 7-73)

U.S. DEPT. OF COMM. BIBLIOGRAPHIC DATA

SHEET

1. PUBLICATION OR REPORT NO. NBSIR 73-40

2. Gov't Accession

No.

3. Recipient's Accession No.

4. TITLE AND SUBTITLE

Field Comparisons of Steel Surveyors' Tapes

5. Publication Date November 1973

6. Performing Organization Code

7. AUTHOR(S)

C. Leon Carroll, Jr.

8. Performing Organ. Report No. NBSIR 73-408 -

9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. Project/Task/Work Unit No. NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

12. Sponsoring Organization Name and Complete Address (Street, City, State, ZIP) 13. Type of Report & Period Covered

SAME

14. Sponsoring Agency Code

15. SUPPLEMENTARY NOTES

This report supercedes NBS Report 10 345

16. ABSTRACT (A 200-word or 7ess (actual summary of most significant information. If document includes a significant

bibliography or literature survey, mention it here.)

Report describes a field procedure to compare a steel

surveyor's tape to a standard tape that has been calibrated by

The National Bureau of Standards. The procedure requires only

a hand-held magnifier, two short scales, and two spring

balances. Temperature reading device is not required since

both tapes are made of steel and have the same temperature

during the comparison.

17. KEY WORDS (six to twelve entries; alphabetical order; capitalize only the first letter of the first key word unless a proper name; separated by semicolons

Graduation; length; scale; tape; temperature; tension.

18. AVAILABILITY Unlimited 19. SECURITY CLASS

(THIS REPORT)

21. NO. OF PAGES

[ For Official Distribution. Do Not Release to NTIS

UNCL ASSIFIED 14

' Order From Sup. of Doc, U.S. Government Printing

Washington. D.C. 20402. SD Cat. No. C13

Office 20. SECURITY CLASS

(THIS PAGE)

22. Price

I ! Order From National Technical Information Service

Springfield, Virginia 22151

(NTIS)

UNCLASSIFIED

USCOMM-DC 29042-P74