Catalog No. E12016

The History of Gauge Blocks

Contents

Preface...............................................................................................................................................................................3
Chapter I The Birth of Gauge Blocks..................................................................................................................................4
The beginning...................................................................................................................................................................................................... 4

Chapter II Manufacture of Gauge Blocks in Japan..............................................................................................................9
Chapter III Production of Gauge Blocks by Mitutoyo........................................................................................................10
Trial manufacture of gauge blocks at the Kamata Factory.................................................................................................................................... 10
Producing gauge blocks for in-house use at the Mizonokuchi Plant..................................................................................................................... 10
Producing gauge blocks for sale at the Utsunomiya Plant.................................................................................................................................... 11
Construction of Numata Research Laboratory and full-scale production of gauge blocks..................................................................................... 13
History of product development and technical development............................................................................................................................... 15
Progress at the Miyazaki Plant............................................................................................................................................................................. 17
History of product development and technical development (continued)............................................................................................................. 19

Afterword.........................................................................................................................................................................222

Preface

Although length is defined by the velocity of light and adefinition of block size, which is now defined as the length

variety of length measuring systems are available based on

between the top measuring face of a block that is wrung to a

the wavelength of a highly stable laser beam, it is gauge

platen of the same material (reference plane) and the surface

blocks that are used as the practical standard of length for theof that platen, thus including the thickness of one wringing

calibration or dimensional reference of measuring tools andlayer. This has the advantage that no wringing film allowance

instruments because of their ease of use, dimensional stability

is needed when calculating the precise size of a stack ofand relatively low cost. Since the use of gauge blocks helps

blocks.

an organization to demonstrate traceability to national length

Requirements for gauge blocks are high dimensional andstandards, gauge blocks are in widespread use in corporations,form accuracy, the ability to wring to other blocks, low secular

universities and laboratories throughout the world.

variation (high dimensional stability over time), excellent

Gauge blocks are equally as useful for the regular inspection

abrasion resistance, a thermal expansion coefficient close to

and calibration of the small tools such as micrometers, calipers

that of common workpiece materials, superior resistance toand dial indicators used in manufacturing industry andrust and corrosion, and so on.

research institutes as they are for calibrating large measuring

Gauge blocks in the size range 0.5mm to 1m are

instruments such as coordinate measuring machines.

manufactured in four grades of accuracy to ISO (JIS) Standards

A gauge block is rectangular with two opposing sides (called

and five grades to ASME Standards. The tightest limits ofthe measuring faces) finished precisely flat and parallel bysize used for blocks that are calibrated mechanically are

grinding and lapping so that the actual distance between±0.3μm for 100mm blocks and ±2μm for 1m blocks inthese two faces is exceedingly close to the nominal size

ISO (JIS) Standards. The highest grade blocks are calibrated

marked on the block. One of the major features of gauge

by interferometer with an uncertainty of measurement

blocks is that a precise length can be obtained by combiningof approximately 0.2μm, with respect to 1m. This value

several gauge blocks of the appropriate sizes by wringing

corresponds to the thickness of a strand of hair with respectthem together, so that they form one cohesive stack. The

to a full circuit of a 400m running track.

wringing phenomenon involves a wringing layer for every

There are two kinds of length standard: line standards andblock in a stack and this fact has had a practical effect on theend standards . A steel rule, a precisely-graduated standard
scale and the international standard meter (obsolete since
the definition of the meter became based on the speed oflight) are all line standards that are read optically. On theother hand, measuring-face-based standards, such as gauge
blocks and length bars, are end standards that are used withcontact methods of comparison. The prototype meter (Meterde Archives, constructed in 1799) was an end standard with
25.3mm x 4mm rectangular end faces, similar to a long gauge
block.
The following chapters describe the birth and history of gauge
blocks, the history of domestic gauge block production in
Japan and the history of Mitutoyo gauge blocks.

Gauge blocks

3Chapter I The Birth of Gauge Blocks

The beginning
The concept of a set of gauge blocks that can be used toassemble a gauge to accurately represent almost any practicallength from a small number of pieces was invented by Carl
Edvard Johansson (Figure 1), a Swedish machinist, in 1896
and therefore has more than a century of history.
Figure 2 illustrates a demonstration of gauge block wringing
force performed by Johansson in 1917 at a mechanicalengineering conference in Stockholm. A total of 200lb (morethan 90kg) of weights were suspended from the lower gauge
block. The wringing force was equivalent to that generated
by a differential pressure of 33 atmospheres on the wrung
surface area.
It is a curious fact that the wringing force often increases with

Figure 2	Demonstration by Johansson at the conference(wringing force equivalent to 33 atmospheres)the time blocks are left wrung together 2 . For this reason it
is unwise to leave gauge blocks in the wrung state for any

based on Johansson's diary under license from Johansson

length of time in case they become inseparable without

Corporation.

risking damage to the measuring faces.

Johansson worked for a rifle manufacturer (Carl Gustaf Stad's

This chapter traces the history of gauge block development

Rifle Factory) in his home town of Eskilstuna as an armoury

based on the article The Master of Measurement – Carl

inspector involved with Remington rifle manufacturing (Figure 3).

E. Johansson serialized in Mitutoyo's in-house magazine

According to Johansson's records, variously shaped gauges

Approach. This history was translated into Japanese by

and a large number of limit gauges used on the shop floor

Nobuo Suga (the former vice-president of Mitutoyo America

were collectively referred to as gauge blocks.

Corporation) from the book The Master of Measurement 3

The top-end reference at the factory in those days was the
micrometer made by Brown & Sharpe Corporation, withwhich the shop-floor gauges were measured and calibrated.
Nowadays, micrometers are calibrated with gauge blocks. The
ranking order between gauge block and micrometer seems
to have reversed around 1906 when the accuracy of gauge
blocks reached the submicron range.
The limit gauges used for inspecting rifle parts were
manufactured specifically for each part, and required
remanufacturing every time a model was renewed or
any part modified. When Johansson visited the Mauser
Corporation in Germany, famous for the Mauser carbine, he
was disappointed to discover that the factory used several
thousand limit gauges. Therefore Johansson thought about

Figure 1 Johansson and his gauge blocks

4The History of Gauge Blocks

Figure 4 Example of wrung gauge blocks
*

30

5
or 3

9
Nominalsize

Figure 3 Johansson at the rifle factory (leftmost in the front row)

* This length depends on the nominal size.
Dimension for exceeding nominal 10mm
(except for 10mm): 35mm
Dimension for nominal 10mm or less: 30mm

combining a minimum number of gauges based on the ideaof 'how to test more dimensions with fewer gauges'.
After taking great pains, Johansson came up with a
combination of 102 blocks that provided about 20-thousand

Figure 5

Johansson type (rectangular type) gauge block

different dimensions from 1mm to 201mm in increments of
0.01mm.
He named this his 'combination gauge block set', which
comprised 49 gauge blocks of 1.01mm to 1.49mm inincrements of 0.01mm; 49 blocks of 0.5mm to 24.5mm
in increments of 0.5mm; and 4 blocks of 25, 50, 75 and100mm.
This idea of obtaining many sizes with a minimum number ofblocks was also adopted in the United States at that time.
Johansson subsequently found an introductory article abouta product called Size Blocks in the American Machinist
magazine. This product was a set of 16 gauge blocks
consisting of sizes from 1/16 inch to 1 inch in increments of
1/16 inch, i.e. a combination of 1/16, 1/8 (=2/16), 3/16, 1/4(=4/16), 5/16, 3/8 (=6/16), · · · · 7/8 (14/16), 15/16, and 1
inch. Upon seeing this article, Johansson hastened to obtain apatent for his gauge blocks.
Although the patent on his gauge blocks was filed in 1898,
the idea was not easily understood by the government.
Consequently, Johansson appealed the patent to the Swedish
royal family and finally got it established in 1908. However,the patent claim was how to use a number of blocks ofdimensions.
The phenomenon of wringing had already been reported by
J. Tyndall (1820-1893) working in the U.K. He pointed outthat "well-ground steel plates are wrung together and theforce is above atmospheric pressure", and that wringing also
occurs in a vacuum (Figure 4). A wringing experiment wasdemonstrated to the public in 1875 at the Royal Society in
London.
The first time Johansson experienced wringing was in1900 when he found that two lapped gauges that weretightly stuck together would not separate when they wereaccidentally dropped.
From the fact that the patent application for gauge blocks
was filed in 1898, two years before his first experience ofwringing, and that nothing about wringing was claimed in
the patent, it can be seen that the idea of 'making up a given
dimension by wringing gauge blocks together' as a major
feature was derived from the acquisition of a high wringing
force due to a process improvement in lapping quality.
Much research has been conducted into the wringing force
phenomenon. As a result it is believed to be primarily due todifferent thicknesses by stacking end-to-end to make up aintermolecular attraction between the material at the surface

given length, without use of the term wringing , so the patentof the blocks themselves and with any liquid (often oil) in

was thus granted on the basis of the idea of a combination of

the wringing film. Surface tension of the oil and differential
5The Birth of Gauge Blocks

Figure 7	Gauge block measuring tool using amodified micrometer

Figure 6 Johansson's house6

air pressure between the exposed surfaces and the wrung

gauge block set in those days.

surfaces are thought to be secondary causes. It is also known

It is said that the gauge block manufacturing process finishedthat the force varies depending on the flatness, surface

at the factory after the surface grinding stage and thenroughness and type of liquid used on the wrung faces. It has

transferred to Johansson's house (Figure 6) for heat treatment,

been established that, if wringing is properly performed, thelapping and inspection, amid great secrecy. A converted

thickness of the wringing film is around 0.01μm (10nm) or

sewing machine was used for lapping and a dedicated toolless.

was used for inspection, in which the thimble diameter ofJohansson's gauge blocks had a 9x28mm rectangular cross-a Brown & Sharpe micrometer was increased to 150mm tosection (9x30/35mm at present). This is because the steel

provide a resolution of one micrometre (1μm) per division andsheet used at the rifle factory to make gauges was 10mm

a deadweight arranged to ensure a constant measuring force

in thickness. This rectangular gauge block is known as the(Figure 7).

Johansson type or rectangular type (Figure 5).

Sweden, being rich in iron ore, is famous for producing high-At first, Johansson's gauge blocks had many problems in spite

quality steel (Swedish Steel) and in fact has been known as theof some successes in trial production. It took 2 years (till 1900)

Iron Country from the time of the Vikings. Johansson carefully

for production to get on track and for the quality to reachselected carbon steel used in gauge blocks in collaborationa level the government required. There was no fixed sales

from C. E. Tahlin, the director of the Wikmanshytte Co.

price at that time and a gauge block set was sold for 500 tosteelmaking plant, and also obtained a great deal of help from700 krona. Sometimes it took a year for a set to be delivered

him regarding the technology of heat treatment.

to the customer. After joining the rifle factory, Johansson

Johansson manufactured gauge blocks so that they assumed

acutely felt the need for industrial knowledge, so he attended

their nominal size at a measurement temperature of 20°C (theindustrial school at night over a period of years and eventuallymean of a factory temperature range of 15 to 25°C), although

graduated. At the same time he was promoted to the positioninternational practice at the time specified 0°C as the standardof apprentice armoury inspector, but his yearly pay was only

measurement temperature. The standard temperature in

600 krona. It would be safe to say that the yearly salary of aindustrial length measurement was not specified to be 20°C

subsection chief or section chief was similar to the price of aby CIPM (Comite International des Poids et Measures) until

The History of Gauge Blocks

1931, and then afterwards by the International Organizationfor Standardization (ISO). The root of the current standard
temperature for length measurement can thus be traced toJohansson's time. Johansson maintained this temperature at
the factory in winter using heating 4 .
The accuracy of gauge blocks manufactured in those earlydays is a matter of great interest. Johansson himself gave "theorder of 1μm (0.001mm)" as the answer to this question.
In 1903 Johansson made a cylindrical reference gauge thatwas just 100mm at 20°C, according to his measurements. He
then asked the International Bureau of Weights and Measuresin Paris to measure the gauge to determine the temperature
at which it measured exactly 100mm, which turned out to be

Figure 9 Johansson gauge made in the U.S.

20.63°C. In other words, this reference gauge was found tohave an error of approximately 0.7μm at 20°C 5 .

was within 0.1μm. From that point onwards Johansson knew

The International Bureau of Weights and Measures (BIPM)

he possessed gauge blocks traceable at an extremely highkeeps the International Standard Mètre platinum-iridium alloylevel to the BIPM.

bar, made in 1889, in safe custody at the originally defined

From 1909 the BIPM conducted scientific research on gauge

environmental conditions under which the length was defined,

blocks, which were then being introduced worldwide, andincluding at a temperature of 0°C. It is said that the accuracyreported favourably on their self-checking capability and highof Johansson's gauge blocks at that time in 1908 was withinreliability.

the range of ±1μm when assembled to a dimension within

Johansson revised the initial 102-piece set by adding a

100mm with each block wrung tightly.

1.005mm block (Figure 8) to create a 103-piece set. In

After that, Johansson made 100mm, 50mm and 25mm gauge

1909 he created a 112-piece set by adding 9 blocks withblocks and again asked the BIPM for an accuracy assessment.

sizes of 1.001mm to 1.009mm in increments of 1μm. ThisIn 1912, he received the result, which was that their accuracy

enabled around 200-thousand dimensions to be available inincrements of 1μm.
Johansson was independent from the rifle manufacturer in1911 and established C.E. Johansson Corporation. After thatthe demand for arms greatly increased due to the outbreakof World War I. Johansson's gauge blocks were used by morethan 450 companies in the world and supplied to both friend
and foe alike.
At that time the U.K. and U.S. differed slightly in the definitionof the inch, as well as the standard temperature at which it
was measured.
The U.K. worked to a length standard known as the Imperial

Figure 8	103-piece gauge block set made by Johansson(1899, Johansson Corporation's possession)Standard Yard (36 inches) and defined the reference
temperature as 62 degrees Fahrenheit (16.67°C). One inch in
7

The Birth of Gauge Blocks

the U.K. was precisely 25.399977mm, based on comparison

or square gauge block (SGB) (Figure 10, left). Gauge blocks ofwith the international standard meter. On the other hand,

this type are used even now in the U.S. (Figure 11 and 12). In

the U.S. defined one inch as 25.4000508mm at 68 degrees

Japan, Mitutoyo Corporation started production and sales ofFahrenheit (20°C) (congressionally determined in 1866), which

this type of gauge block in 1982.

amounted to a difference of less than 3 parts per million.
Johansson actually manufactured inch gauge blocks assuming
1 inch was exactly equivalent to 25.4mm at a temperatureof 20°C. In later years when the inch definition between
the U.S. and U.K. was unified to agree with this definition,
Johansson's gauge blocks had penetrated widely in theweapons industry, which then could not help but conform toJohansson's definition. As a result, Johansson might be seenas the originator of the current definition of the inch.
Johansson's gauge blocks were also used at the National

Figure 11 Using square gauge blocks to calibrate an electronic caliper

Bureau of Standards (NBS) and were declared to be strategic

goods . A million pieces (11,000 sets) of his gauge blocks had
been manufactured by 1929. At this time Johansson went
over to America and started production of U.S.-made gauge
blocks (Figure 9) in collaboration with Henry Ford (1863-1947)of the Ford Motor Company.
The National Physical Laboratory (NPL) in the U.K. succeededin trial manufacture of gauge blocks in about 1918, after
which the Pitter Gage Precision Tool Company started
production and sales. Hommel Corporation and othercompanies also sold gauge blocks.
In the U.S., in 1917, a National Bureau of Standards (NBS)
employee, W. E. Hoke, invented a round (later, square) gauge
block with a hole in the middle (Figure 10, right). This designof gauge block enables assembling a stack of blocks with athreaded rod and screws and is referred to as a Hoke Gauge

1

24.

24.

1
Nominal
size

6.7mm
hole

Hoke gauge
Square typeFigure 108Round Hoke gauge blocks witha hole invented in 1917.

Figure 12 Using square gauge blocks in a height comparison measurement

Chapter II Manufacture of Gauge Blocks in Japan

Gauge blocks were manufactured and sold for the first time inJapan by Taisuke Tsugami (1893-1974)

6,7

as gauge block personnel. Meanwhile, Kure Naval Arsenal. He started researchpromoted the development of gauge block technology. In

on the domestic production of gauge blocks in 1923 and1935 Toyo Kogyo Co., Ltd. introduced the technology fromestablished Tsugami Seisakusho Co., Ltd. in 1928 (renamed

the arsenal and started production and sales of gauge blocks.

later, Toyo Seiki Co., Ltd. and currently, Mitsui Seiki Kogyo Co.,

Nachi-Fujikoshi Corp. started gauge block production inLtd.). The company received an industrial incentive payment

1937, and a year later so did the SEKI KOUHAN FACTORY

of 10-thousand yen from the Industrial and Commercial(presently SEKI KOUHAN, LIMITED). Then, in 1955, Mitutoyo

Department and set up an advanced facility with equipment

Manufacture Co., Ltd. (presently Mitutoyo Corporation)from the top manufacturers, such as a constant temperaturestarted sales of gauge blocks and in 1965, Showa Seiko Co.,and humidity room, Zeiss interferometer and SIP jig borer.

Ltd. in Hiroshima started full-scale marketing 9 .

His company succeeded in trial manufacture in 1931 andstarted production and sales of gauge blocks under the Mitsui
Seiki Kogyo brand label in 1934.
Taisuke Tsugami had confidence in the quality of his
company's gauge blocks and regretted that clients did not
believe in their quality merely because they were domestic
products. At that time the military and naval factories had
Johansson gauge blocks that were regarded as the best in
the world. Taisuke Tsugami borrowed those gauge blocks
to check the dimensional stability and made a presentationof the report to the U.K. technical magazine Engineering .
Meanwhile, Johansson presented the research result on
Tsugami's gauge blocks to the Precision Measurement

Association Magazine . The debate continued for 3 years.
After that, Tsugami conducted full-scale production of gauge
blocks in 1937 at Tsugami Seisakusho Co., Ltd. (presently
TSUGAMI Corporation, taking over Toyo Seiki Co., Ltd.)established at Nagaoka in Niigata Prefecture, in addition to
Mitsui Seiki Kogyo Co., Ltd.
Following Tsugami's pioneering lead in Japan, Saburo Kuroda 8
the founder of Kuroda Gauge Manufacturing Company(presently Kuroda Precision Industries), who was independent
from SONOIKE MFG. (presently AMADA), succeeded in
the development of gauge blocks in 1934 and started fullproduction in 1935.
The military and naval forces were enthusiastic aboutengaging in domestic production of gauge blocks, probably
starting production sometime around 1934. Fifty or moreworkers might have worked for Kokura Military Arms Factory9Chapter III Production of Gauge Blocks by Mitutoyo

Figure 15	Model of Kamata Factory (built by Taro Morioka of Kogeisha).
Figure 13 Yehan Numata, the founder of Mitutoyo

the same year he finally succeeded in manufacturing good
Mitutoyo started producing gauge blocks along with domestic

quality micrometers and from the next year, 1937, sales

production of micrometers 10 . Yehan Numata (1897-1994,

commenced (Figure 14).

Figure 13), the founder of Mitutoyo Manufacture Co., Ltd(presently Mitutoyo Corporation), who was a statistics officerof the Cabinet Resource Department at that time, got the

Trial manufacture of gauge blocks
at the Kamata Factoryidea of business promotion for the purpose of gaining funds
for Buddhism missionary work. In 1934 he established a

Micrometers were inspected at the time using Johansson

research laboratory at Musashi Shinden in Tokyo and launchedgauge blocks. Research on gauge blocks was started at thedomestic production of micrometers, which were thenKamata Factory with a view to self-manufacture and trial

imported goods, with several persons employed.

manufacturing of them in 1941 proved successful.

However, the business did not yield the quality of results hedesired, so he resigned from his government post to focus on
his business and constructed a factory at Kamata in Tokyo,

Producing gauge blocks for inhouse use at the Mizonokuchi Plant

naming it Mitutoyo Manufacture (Figure 15). Repeating trial
manufacture and evaluation many times, in December of

In 1940, the Mizonokuchi Plant (Figure 16) at Kawasaki in the
Kanagawa Prefecture went on-line for mass production of
micrometers and the output rose to 1,000 pieces per month.
Mitutoyo started production of gauge blocks at theMizonokuchi Plant, where from 1942 gauge blocks were mass
produced for in-house use to inspect micrometers.
At that time, Mitutoyo used the Zeiss Ultra Optimeter andHorizontal Optimeter for inspection of gauge blocks and,in the next year, succeeded in trial manufacture of its own
electrostatic capacitance electronic micrometer.

Figure 14 Mitutoyo's first micrometer (1937)

10

The History of Gauge Blocks

The Mizonokuchi Plant continued minimal productionof micrometers to preserve the associated production
technologies. Additionally, the Hiroshima Research Laboratory,
founded at Shiwa in Hiroshima Prefecture, the founder'sbirthplace, commenced production of micrometers in 1947 bydemobbed employees, along with existing personnel.
In 1949, in accordance with the founder's original intention,
Mitutoyo restarted production of micrometers at theMizonokuchi Plant and also started production of calipers andFigure 16 Mizonokuchi Plant

Producing gauge blocks for sale atthe Utsunomiya Plant

height gages at the Utsunomiya Plant.
The first time Mitutoyo made sales of gauge blocks was in1955 when the Utsunomiya Plant produced the 8-piece gauge
block set for micrometer inspection (Figure 18).
A measuring instrument of the highest accuracy is essential

In 1944 the Utsunomiya Plant (Figure 17) started operation,

to the production of gauge blocks. Some very high-accuracy

after which the production of gauge blocks was transferredmeasuring instruments were developed by Mitutoyo inthere. In 1945 the Kamata Factory was lost due to war damage

tandem with gauge blocks production.

and the Mizonokuchi Plant was also closed temporarily.

To illustrate examples of these measuring instruments, inSince the domestic market collapsed after World War II,

1957 the Utsunomiya Plant manufactured the gauge block

the production of measuring instruments could not be kept

inclination adjusting device on the built-in gauge block

going because of a sharp downturn in demand. Mitutoyo

measuring instrument in a constant temperature tank supplied

only continued operation with the Utsunomiya Plant that,to the Central Inspection Institute of Weights and Measuresduring this period, produced daily commodities such as

and, in 1953 and 1960, the interferometric length measuring

electric heaters, hair clippers and kitchen knives to support

system on the interferometric standard barometer developed

the livelihood of employees. The Utsunomiya Plant thenby the Central Inspection Institute of Weights and Measures.

manufactured wooden pipes for spinning, automated

In 1964, the second upgraded version of this barometer was

weighing machines and automated weighing and sorting

adopted as the standard laboratory barometer in Japan.

machines for caramel candies, sticks of chewing gum,
Ajinomoto condiments and golf balls, etc., while plant
management planned an early recovery.

Figure 17 Utsunomiya Plant

Figure 18 Gauge block set for micrometer inspection

11

Production of Gauge Blocks by Mitutoyo

Height Masters ) (Figure 21) by using stacked gauge blocks.
Although the Height Master (and associated Check Master )design has been changed a few times, they have been used
regularly by customers for more than half a century andrepresent a truly enduring product (Figure 22, 23 and 24).

Figure 19 Riken-system InterferometerIn 1958, a Riken-system interferometer (using the comparative
method of measurement) (Figure 19) was produced
experimentally and high-accuracy dial indicators with aresolution of 1 μm were put into production. The Utsunomiya
Plant developed a high-accuracy digital micro indicator using a
differential transformer in 1961, and the Research Department

Figure 21	Original Height Master (height checkmicrometer)at Mitutoyo headquarters developed the high-accuracy
Okoshi-system surface roughness tester AA-1 with anenhanced magnification of 24,000X in 1962. Meanwhile, theResearch Department at Mitutoyo headquarters developed the
Ultra Comparator with a resolution of 0.01 μm (Figure 20) byusing the principle of a strain gauge in 1962. This comparator
received an award as one of the Nikkan Kogyo Shinbun Ten
Big New Products in the next year.

Figure 22 Current Height Master (analog type)

In 1957 the Mizonokuchi Plant commenced production ofheight check micrometers (height standards, later renamed

Figure 23 Current Height Master (digital type)Figure 20 Ultra Comparator

12

Figure 24 Current Check Master

The History of Gauge Blocks

Construction of Numata ResearchLaboratory and full-scale
production of gauge blocks
In 1940 the Numata Research Laboratory (Figure 25), later
the factory dedicated to gauge blocks, was constructed
for R&D in measuring instruments in the Shonan area ofChigasaki in Kanagawa Prefecture (nearest station: Tsujido

Figure 26 New factory of Numata Research Laboratory (1966)

on the Tokaido line). However, since it was difficult to importlaboratory machines from German companies during World

Precision Industries made up 40% of the total domestic sales.

War II, the establishment was used as a recreation facility for

Regardless of sales of gauge blocks for micrometer inspection

employees. Eventually, in 1961, the laboratory reverted tosince 1955, Mitutoyo did not secure a strong market positiona factory producing micrometers, micrometer heads, insidebecause of a limited choice of blocks and less sales volume

micrometers, etc.

than other companies at that time.

Toshihide Numata, director (presently a Mitutoyo senior

In 1967, Mitutoyo-brand gauge blocks were introduced to theadviser, 1932- ), who is the eldest son of the founder, andmarket on a full-scale basis. The Numata Research Laboratory

Hiroshi Sasaki, plant manager (former Mitutoyo vice-president)

was rebuilt to become a dedicated gauge block facility andmanaged its operations.

a new two-storey plant was completed in 1966, constructed

According to statistical information from the Ministry offrom well-insulated concrete block and equipped with aInternational Trade and Industry concerning the domestic

constant-temperature room.

gauge block sales situation at that time, the total amountIn the same year, the production of gauge blocks wasof gauge block sales in four companies: Tsugami, Kuroda

transferred from the Utsunomiya Plant to this plant where

Precision Industries, Toyo Kogyo and Nachi-Fujikoshi in 1962

machining and heat-treatment equipment was relocated, or

was 140 million yen a year, and that in five companies,

newly acquired, and a dedicated heat treatment room wasincluding Showa Seiko in 1965, it was 250 million yen a year.

constructed. A lapping machine developed at the Mizonokuchi

The total sales in 1967 was 290 million yen.

Plant was also introduced.

Among those companies, Tsugami's gauge blocks commanded

As a background to the entry into full-scale marketing ofnearly an 80% share of major users and those from Kuroda

Mitutoyo gauge blocks, MTI Corporation (founded in 1963
as a local sales subsidiary in the U.S.) had made a request foran early launch of them onto the market. Mitutoyo madea production plan from the start with a view to the world
market by manufacturing products premised on compliancewith American Standards and domestic standards (as well as
German Standards).

Figure 25	Numata Research Laboratory at the time of starting operations(1961)

13

Production of Gauge Blocks by Mitutoyo

manufacturers were also promoting a shift to machine lappingat that time.
Inspection facilities, including in-house digital micro indicators,
interferometric flatness measuring instruments and the
Koester Interferometer (Figure 28), were relocated and Zeiss
Optimeters (Projektions Optimeter) were introduced. Mitutoyotransferred young employees to the Utsunomiya Plant fortraining in lapping and machining and to the Metrology
Research Laboratory, an Agency of Industrial Science
Technology in the Ministry of International Trade and Industry
Figure 27 Gauge block lapping (1966)

for the acquisition of interferometric measurement technology.
Additionally, three veteran employees were transferred fromThe factory first started production of discrete gauge blocks

the Utsunomiya Plant to the latter.

and then 81-piece block sets (inch sizes). The production

The factory also produced the special gauge blocks for

output reached 1,000 pieces a month in the first year andHeight Masters in addition to standard gauge blocks. In the

10,000 pieces a month the year after.

same year, Mitutoyo commenced sales of the Digital Height

Lapping of gauge blocks (Figure 27) requires a lot of skill.

Master (counter separation type), which was our first digital

Although this had been a hand process for many years, mass

product. Since 1968, Mitutoyo has participated in Gauge

production was implemented from the start by introducing a

Block Round-robin Measurement Comparisons (comparison oflapping machine. This was because machine lapping made itmeasurement accuracy started in 1955 among manufacturers,

possible to manufacture high quality gauge blocks with a highlaboratories and major users that have interferometers)

degree of flatness and parallelism and little variation in size

under the auspices of the Research Laboratory of Metrology,

at low cost, without resort to skilled workers. Other domestic

intending to maintain traceability and improve measurement
technology.

Figure 29 Inspecting gauge blocks (1966)

Figure 28	Koester interferometer (Interference Comparator madeby Carl Zeiss Jena Corporation in former East Germany)

14

The History of Gauge Blocks

History of product development
and technical development
This chapter traces the history of Mitutoyo's gauge block
product and technology development.
1970
Enhanced the range of gauge block sets offered andachieved full-scale entry into the market (103-, 76-, 56-,
47-, 32-, 18- and 9-piece metric sets, and a 10-piece set

positioning unit in addition to automatic calculation,
grade judgment and error judgment functions using acomputer, which later boosted its sales to several major
outside users. Monthly production of 40,000 pieces wasachieved.
1974
Developed an 8-piece set of long gauge blocks (Figure 32)
and a 10-piece set of all-tungsten carbide gauge blocks
for calibrating micrometers.

for calibrating micrometers). In this year the serial number
marking method was improved from that of engravingwith a pantograph to that of imprinting by means ofphotographic film in order to attain clearer letters inadvance of other manufacturers (Figure 30).
1972
Started production of 2mm-base gauge block sets. Thisset was designed to ease the wringing operation bychanging the base dimension from 1mm to 2mm. Thisis because thicker gauge blocks are flatter and therefore

Figure 31	Calibrating gauge blocks with the original automatic calibration
testerwring more readily. Monthly production of 30,000 pieces
was achieved.
1973
Started production of tungsten carbide gauge blocks.
Developed Mitutoyo's first automatic gauge block
calibration tester (Figure 31). This development made it
possible to perform measurement of ultra-high precision
gauge blocks efficiently without requiring special skills.
This epoch-making tester was provided with differential

Figure 32 Long gauge blocks

transformer-type high precision sensors and a cam-type

Figure 30 103-piece gauge block set (manufactured by Mitutoyo)

15

Production of Gauge Blocks by Mitutoyo

1975
Started production of long gauge blocks ranging froma nominal size of 600mm to 1000mm. Succeeded indeveloping the world's first ultra-thin gauge blocks ofnominal size 0.1mm (Figure 33).

Figure 33 Ultra-thin gauge block set

1981
The 20th anniversary of the start of production at the
Numata Research Laboratory. A total production of 5
million pieces had been achieved.
1982

Figure 34 Square gauge blocks

1984
The Automatic Interferometer for Long Gauge Blocks(Figure 35), developed by the Measurement Technology
Research Laboratory, was introduced into the Numata
Research Laboratory where the measurement of longgauge blocks up to a nominal size of 1000mm had been

Started production of square gauge blocks In response to

made possible. In this interferometer the technology

demand from the U.S. (SGB, Hoke-type) (Figure 34).

employed by Mitutoyo for manufacturing the holder

Founded the Measurement Technology Researchpart when the trial production of the 1m-interferometer

Laboratory on the Mizonokuchi site and started thewas carried out at the Central Inspection Institute ofwavelength calibration business for lasers available

Weights and Measures, Agency of Industrial Science andfor absolute measurement of gauge blocks. The laser

Technology (later the Research Laboratory of Metrology)

wavelength calibration system was developed in thein 1957 was utilized. In Japan, this interferometer is usedfollowing year, at which time Mitutoyo's standard supply

only by Mitutoyo and the National Institute of Advanced

system was complete.

Industrial Science and Technology (AIST, the former
Research Laboratory of Metrology), which is one of the
public research agencies.

Figure 35 Interferometer for measuring long gauge blocks

16

The History of Gauge Blocks

Up until then the scale of production of gauge blocks had also
expanded and, therefore, the space available at the Numata

Progress at the Miyazaki Plant

Research Laboratory had become insufficient for reinforcing/augmenting the production facilities. Moreover, since there
was a strong welcome initiative at that time from Miyazaki
Prefecture a plan to found a factory there emerged, andMitutoyo decided to transfer the manufacturing base forgauge blocks to Miyazaki Prefecture by the end of the year.
Practical use of fine ceramics as industrial materials progressedin the 1980s on account of their obvious advantages,
including greater hardness and wear resistance and theircorrosion-free nature as compared to steel, which suggested
the possibility of applying them to gauge block manufacture.
In the same period, also at the Numata Research Laboratory,
the development of ceramic gauge blocks was started. After
performing several trial production runs and evaluating gauge
blocks using various kinds of ceramic materials, they reached
the conclusion that zirconia was the most promising. In 1985

Figure 37	Miyazaki Mitoyo Precision Co., Ltd. (presently Mitutoyo Miyazaki
Plant Co., Ltd.)In October 1985 the production of gauge blocks moved
from the Numata Research Laboratory to Miyazaki (Miyazaki
Prefecture Tano-Cho Tsukijihara Industrial Complex) located in
the south of the country.
The Miyazaki Plant (Figure 37) was Mitutoyo's 12th factoryin Japan and is a state-of-the-art facility dedicated to gauge
block production. It has a large precision measurementa trial was made by manufacturing wear gauge blocks (nominal

room located 5.5m underground to ensure the most stable

1mm and 2mm sizes) from zirconia ceramic, and they wereenvironmental conditions.

introduced at a private exhibition. As to commercialization,

At this time the production of Height Masters (including Check

there still remained the need to reduce material cost and solve

Masters), which had always been produced in the Utsunomiya

some outstanding technical issues (Figure 36).

Operations, was also transferred to the Miyazaki Plant. Next
year the production of long square gauge blocks (SGB) started.
The Miyazaki Plant was founded as the Miyazaki Mitutoyo
Precision Co., Ltd., as one of the Mitutoyo affiliates and,five years later, its name was changed to Miyazaki MitutoyoCo., Ltd., and then changed again to Mitutoyo Hiroshima
Operations Co., Ltd., in 1993. Later it became the Hiroshima
Operations Miyazaki Manufacturing Department and lastly,since April 2009, has become the Miyazaki Plant.
Below is a brief review of the characteristics which a steel
gauge block should possess and the method of manufacture.

Figure 36	Mitutoyo steel gauge blocks (back) and ceramic gauge
blocks (front)

First of all, steel gauge blocks are required to be subject tominimum variation in their size due to wear from normal use,
i.e. wringing, etc. To achieve this, gauge blocks must have a
Vickers Hardness (HV) of 800 or more. Therefore high-carbon
steel, which is easily hardened through quenching (rapid
cooling after heating), must be used as the base material(Figure 38). For commercial production a special carbon tool17

Production of Gauge Blocks by Mitutoyo

Figure 38 Heat treatment line

Figure 40 Heat processing/forming line for ceramics

steel alloy is used. If such material is rapidly cooled (quenched)in water or oil after heating, in a similar way as quenchinga Japanese sword, its crystal structure is transformed into avery hard form. After hardening various kinds of stabilizing
processes, including tempering and annealing, are applied.
The dimensional stability requirement (the amount of secularchange permitted) for a gauge block is very high, and isdefined by one International Standard (ISO3650) to be
0.045μm or less per 100mm per year, and 0.27μm or less per
1m per year in the case of Grade K or 0 (zero) gauge blocks.
Therefore, every gauge block manufacturer makes strenuous
efforts to suppress possible secular change by devising special
heat treatment methods for relieving residual process stresses
in their steel gauge blocks that otherwise would reduce
performance.
In 1988 Mitutoyo started full-scale production and sales of theworld's first zirconia ceramic gauge block called CERA block(rectangular type) (Figure 39).
This snow-white gauge block has remarkable characteristics
including extreme resistance to wear, requires no special
handling (non-corroding) and has very low secular change,

properties that have traditionally been the weakest pointsof steel gauge blocks. In addition, the thermal expansion
coefficient is close to that of steel gauge blocks, so CERA
blocks can be used as direct replacements for steel blocks
without the need for temperature corrections when working
with steel workpieces.
This is in contrast with tungsten carbide gauge blocks,
conventionally marketed as a block with high wear andabrasion resistance, that have a thermal expansion coefficient
only half that of steel blocks and a modulus of elasticity
very different, so they cannot be used easily with steel
components, requiring careful thought and precautions whenusing them to avoid the risk of dimensional errors arising.
The wear and abrasion resistance of CERA blocks is at least
10 times better than steel blocks, and secular change iseven less than the uncertainty resulting from interferometermeasurement, so is practically zero.
Furthermore, to allay any user concerns about the perceived
fragility of ceramics, the material used for CERA blocks has
been made very chip-resistant by implementing an integrated
production system from raw material to finished product(Figure 40) that includes investment in advanced heatprocessing plants and factories dedicated to ceramics, which
has also achieved high quality assurance and a competitive
cost for this product.
In advance of these actions, Mitutoyo employed university
graduates in ceramics and dispatched trainees to the JapaneseFine Ceramics Center in Nagoya in order for them to masterthe heat processing/forming techniques that were needed.
As a result of these efforts there have been almost nocomplaints regarding chipping or cracking of CERA blocks

Figure 39 CERA block18

The History of Gauge Blocks

from users since the introduction of this exceptional productto the market. Thereafter, even though gauge blocks
featuring zirconia began to be marketed by other vendors
both from within Japan and overseas, still the CERA block isviewed throughout the world as the epitome of a ceramic
gauge block, demonstrating the many eminent features of its
type such as long life, freedom from corrosion and extreme
resistant to wear.

History of product development
and technical development(continued)

Figure 42 Automatic Gauge Block Interferometer (GBI)

1994
1990
Started the production of long CERA blocks up to anominal size of 500mm (Figure 41).

Aimed to improve accuracy in comparison measurements
by introducing the Calculation Type Automatic Gauge
Block Interferometer (Figure 43) with Bidirectional Touch
Signal Probe, which was developed at the Kawasaki
Research and Development Center (MKC). Acquired thecertification of the first JCSS (Japanese Calibration Service
System)-authorized calibration laboratory in gauge block
calibration based on the Measurement Law, and the
Tsukuba Research Laboratory acquired the accreditation of
JCSS-authorized calibration laboratory in laser wavelength
calibration. Miyazaki Plant acquired the accreditation

Figure 41 Long CERA blocksof ISO9002 (quality system of the International
Standardization Organization), which was the first within

1991

Mitutoyo's domestic organization.

Started the production of square CERA blocks.
1992
Achieved the total cumulative production of five million
pieces at the Miyazaki Plant.
1993
The Automatic Gauge Block Interferometer (GBI) (Figure 42)
developed at the Kawasaki Research and Development
Center (MKC) was introduced. This interferometer isprovided with a function to automatically read interference
fringes, thus contributing to the improvement of bothaccuracy and efficiency in interferometric measurement.
Up until then, Mitutoyo had used interferometers
manufactured by Zeiss for many years.

Figure 43 Calculation Type Automatic Gauge Block Interferometer19

Production of Gauge Blocks by Mitutoyo

1995
Acquired accreditation as a calibrating organizationthat conforms to ISO/IEC 17025 (general requirements
regarding the capability of a test station and calibratingorganization which is defined by the International
Standardization Organization) from RvA NKO (theNetherlands Calibration Association / Netherlands
Accreditation Organization). Since the JCSS Calibration
Certificate issued by Mitutoyo for a gauge block isunder the endorsement of MRA (Mutual Recognition
Agreement) accreditation based on APLAC (AsiaPacific Laboratory Accreditation Cooperation) and ILAC
(International Laboratory Accreditation Cooperation), it
is also valid in each country (Western and Asian Nations)affiliated to these organizations. Against this background,
Mitutoyo planned to introduce the second version of theAutomatic Gauge Block Interferometer (GBI) that used
two laser wavelengths.
1998
Started production of the world's first low-expansion
glass gauge block, developed as a reference standard insupport of the trend toward temperature-compensatedprecision coordinate measuring machines (CMMs) (Figure

Figure 44	Calibration of a high-precision coordinate measuring machine with
low-expansion glass gauge blocks

2000
Started to sell the 122-piece set which contained thelargest number of gauge blocks ever marketed.
2002
Launched the technology development to process onepiece gauge blocks made to a special dimension (customerspecified dimension). Shortened the delivery period forspecial dimension gauge blocks, and thus gained manycustomers.
200344). Because successful operation of this type of CMM

Announced the introduction of mixed sets of steel blocks

depends on knowing the effect of temperature differences

and CERA blocks. These sets offered increased resistance

between a workpiece and the CMM scales, a smaller

to wear by using CERA blocks for those blocks that are

gauge block with a much smaller coefficient of thermal

most frequently used in normal use. This development

expansion is required in order to minimize uncertainty inwas to meet customer demand for a lower priced, but still

the calibration that establishes this relationship. In thislong lasting, gauge block set.

year, falling as it did on the 10th anniversary of the initialsales of the CERA block, Shunji Sudo (vice plant manager
and quality control section chief of Miyazaki Plant), madeAchieved the world's highest performance level ina research presentation on the phase compensation of

the interferometer measurement capability of gauge

a CERA block at a meeting of the International Society

blocks among JCSS authorized calibration laboratories

for Optical Engineering, SPIE) held in Europe. The(Uncertainty of Measurement = 0.03 micrometre/100mm).

speech concerned the report addressing reliability of theinterferometric measurements of CERA blocks which had
already been widely disseminated.

20

2004

The History of Gauge Blocks

2005
Developed the Mitutoyo-original non-contact typeinterferometer which can measure the thermal expansion
coefficient of gauge blocks to high accuracy.
2006
Started selling the world's first gauge blocks (Steel/CERA
blocks) (Figure 45) designed for applications requiring
blocks calibrated not only for size but also for coefficientof thermal expansion.

Figure 47 Micrometer-check gauge block holder (developed in 2002)

Figure 45	Gauge block with a calibrated coefficient of thermal expansion

2009
Developed the world's first ceramic gauge block with anegligible thermal expansion coefficient. This Zero CERA
block (Figure 46) has been used by universities and researchorganizations, in addition to major company customers, for

Figure 48 122-piece gauge block set (developed in 1999)

research regarding the calibration of coordinate measuringmachines and other high-precision applications.

Figure 46 Zero CERA block21

Afterword

The year 2012 marks 70 years since Mitutoyo first started production of gauge blocks. Since the time when the Numata ResearchLaboratory entered the market on a full-scale production basis, the production of Mitutoyo gauge blocks now exceeds a total of 23
million pieces in 45 years, and they continue to be used all over the world. Advanced processing techniques have been cultivatedby Mitutoyo over the years with its research and development advancing measurement technology and creating new products,
such as new types of gauge block, as well as leading-edge
measurement equipment for gauge block evaluation. With areputation for innovation and reliability endorsed by history,
and an extensive sales/service network stretching throughout
the world, Mitutoyo continues to support manufacturingindustries wherever they may be found.

Written by Tetsuo Kosuda, the Miyazaki Plant Manager.

22

Figure 49 Mitutoyo Miyazaki Plant, Co., Ltd.

<<The History of Gauge Blocks>>
First edition: January, 2013
Not for sale
Publisher: Mitutoyo Corporation
1) Kesakatsu Koizumi (1961). History of Weights and Measures. Central Inspection Institute of
Weights and Measures of the Agency of Industrial Science and Technology.
2) Tamotsu Aoki (1933). Precision Measurement and Measuring Instruments. Maruzen.
3) Nobuo Suga. The Master of Measurement - Carl E. Johansson. Serial article carried in the inhouse newsletter Approach of Mitutoyo Corporation. Based on a Japanese translation of Carl
Edvard Johansson: The Master of Measurement (Johansson).
4) Masaji Sawabe: Normal Temperature in Industrial Measurement - Circumstances of Its
Establishment and the Problems. Research of Machines (2001), Vol. 53, No. 7.
5) Ted Doiron. 20°C - A Short History of the Standard Reference Temperature for Industrial

8) Kuroda Precision Industries, Ltd. 70-Year Magazine.
9) Mikuro (1978). Japanese Precision Measuring Instruments Association's Memorial Magazine
for the 20th Anniversary of Foundation.
10) The following documents/materials of Mitutoyo Corporation:· Shokichi Miyazaki: Searching for the Root of Measuring Instruments - Micrometer, VernierCaliper, and Gauge block (Mitutoyo Museum)· History of Mitutoyo - Guiding the Numata Memorial Hall (Mitutoyo Numata Memorial Hall)· Sasaki Hiroshi Lecture Record: 50 Years of Mitutoyo Gauge Blocks (1998)· Mitutoyo Numata Memorial Hall

Dimensional Measurements. Journal of Research of the National Institute of Standards and· Facilities and source materials possessed by the Mitutoyo Museum

Technology (2007), 112, 1-23.

· Mitutoyo 50-year magazine

6) Taisuke Tsugami: Gauge Blocks and Myself. Mikuro: Japanese Precision Measuring Instruments
Association's Memorial Magazine for the 20th Anniversary of Foundation (1978).
7) Kenzo Tsugami (1962). Factory Measuring Instrument Lecture 8 Block Gauge. Nikkan Kogyo
Shimbun.

· Mitutoyo Mizonokuchi Plant 50-year magazine· Mitutoyo Utsunomiya Operations 50-year magazine· Mitutoyo Miyazaki Plant 10-year magazine· Mitutoyo Catalog and Website Home Page

Copyright © Mitutoyo Corporation 2013
The contents of this document are protected by law. Do not reproduce, reprint, quote, or modify without permission.

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