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How to Select the Optimum Preferred Metric Sizes and Help Cut Manufacturing Costs

Choose the best metric standard sizes and compete on the global market.

Last modified: 2012-10-16

Preferred Metric Sizes, Tolerance Zones and Fits               

TABLE 1 Preferred Metric Sizes

TABLE 2 Fastener Sizes

TABLE 3 Metal Sheet Sizes

TABLE 4 Steel Plate Sizes

TABLE 5 Tolerance Zones for Holes

TABLE 6 Tolerance Zones for Shafts

TABLE 7 Round Steel Bar Tolerances

TABLE 8 Preferred Fits

How It All Started

Industry Users of METRIC STANDARDS Book, Software or Consulting Services

   How do you select the optimum metric sizes when you design a new metric product? Will material stock, cutting tools, fasteners, etc. be readily available where parts are to be produced?  If not, this may cause a cost penalty and added manufacturing time. If you select from the First, Second or Third choice sizes shown in TABLE 1 Preferred Sizes, you will ensure that design and manufacturing practices follow the established global metric standards.

   The selection of a preferred size in the customary inch system has been helped by the fractional system to some extent.  In the inch design you would select the whole inch sizes first, and then in increments of 1/2, 1/4, 1/8, etc.  The metric system does not use fractions, and there are 25.4 millimeters sizes to choose from in each inch.  This is why the preferred numbering system or the preferred metric sizes (ISO 497 R''20 and ANSI B4.2) is so important to use in all metric product designs. For more details see: the METRIC STANDARDS for Worldwide Manufacturing books listed.

   Changing to the metric system presents an opportunity for companies to unify metric standards worldwide and encourage the use of more interchangeable parts.  These can be mass produced in fewer varieties which benefit consumers and producers alike. 

   To make parts interchangeable, other factors must also be interchangeable, such as the nominal size of a part, its tolerances, and material quality.  A bolt, for example, must have the same physical size, tolerance, coating and strength class.  Steel plates are interchangeable when the thickness, size, tolerance, and the steel quality are sufficiently close to swapping one manufacturer to another.  More importantly, purchasing interchangeable parts and components around the world provides an opportunity to reduce manufacturing costs.

Preferred Metric Sizes

   The preferred numbering system has played a major role in the development of metric standards. This is a geometrical series of numbers adopted worldwide. Its first known application was in the 1870’s by Charles Renard, a French army captain who reduced the different diameters of rope for military balloons from 425 to 17. The R5, R10 and R20 series refers to the Renard 5 (first choice sizes 60 % increments), Renard 10 (second choice sizes 25 % increments) and Renard 20 (third choice sizes 12 % increments) series of preferred numbers, see ISO 3.

   Nominal metric sizes are identical where the metric system has been in use for several years.   Here is how the preferred metric nominal sizes were developed and how these chosen sizes reflect preferred metric standard sizes for threaded fasteners, metal sheets, steel plates, bars, etc already in use throughout the world.

   How do the preferred metric sizes relate to the customary inch sizes and the preferred numbers are shown in TABLE 1.

TABLE 1 Preferred Metric Sizes (ANSI B4.2)

Preferred Sizes mm 

 

Preferred Sizes Inch

 

Preferred Numbers 

First

Second

Third

mm

Fractions

Decimals

First

Second

Third

R5"

R10"

R20"

 

 

 

R5

R10

R20

4

 

 

3.97

5/32

0.156

4

 

 

 

 

4.5

4.37

11/64

0.172

 

 

4.5

 

5

 

4.76

3/16

0.188

 

5

 

 

 

5.5

5.56

7/32

0.219

 

 

5.6

6

 

 

6.35

1/4

0.25

6.3

 

 

 

 

7

7.14

9/32

0.281

 

 

7.1

 

8

 

7.94

5/16

0.313

 

8

 

 

 

9

8.73

11/32

0.344

 

 

9

10

 

 

9.53

3/8

0.375

10

 

 

 

 

11

11.11

7/16

0.438

 

 

11.2

 

12

 

12.7

1/2

0.5

 

12.5

 

 

 

14

14.29

9/16

0.563

 

 

14

16

 

 

15.88

5/8

0.625

16

 

 

 

 

18

17.46

11/16

0.688

 

 

18

 

20

 

19.05

3/4

0.75

 

20

 

 

 

22

22.23

7/8

0.875

 

 

22.4

25

 

 

25.4

1

 

25

 

 

 

 

28

28.58

1 1/8

1.125

 

 

28

 

30

 

30.16

1 3/16

1.188

 

31.5

 

 

 

35

34.93

1 3/8

1.375

 

 

35.5

40

 

 

39.69

1 9/16

1.563

40

 

 

GO

STOP

CAUTION

 

    The ANSI preferred metric sizes are identical to those in the ISO 497 R20'' rounded series selected years ago. The intent of the number series shown is to help reduce the number of standard sizes for screw threads, metal sheets and plates,  round metal bars, lifting capacities, hydraulic cylinder diameters, etc.

The preferred size range from 4 through 40 mm may be extended to cover smaller or larger sizes by just multiplying or dividing sizes shown by 10. For instance, 60-mm sizes would be a preferred choice as would 2.5-mm devices.

   For example, the six first choice thread sizes shown in TABLE 2 are recommended to replace the 61 other thread sizes listed. The first choice sizes are according to the R5" series of preferred sizes shown in TABLE 1.  Less savings will be achieved if you select the twelve ISO (green) first and second choice sizes shown or the 14 ANSI (bold) first choice sizes. The cost reduction becomes substantial when you figure thousands of dollars savings for each unique fastener size that can be eliminated from the product design.

 TABLE 2 Fastener Sizes

ISO 262 Metric (mm)

Unified Inch

Coarse

 

Coarse

Fine

 

Coarse

Fine

R5"

R10"

R20"

 

mm

Inch

 

M2.5

 

 

 

2.51

#3-48

#3-56

 

M3

 

 

2.8

#4-40

#4-48

 

 

 

 

3.2

#5-40

#5-44

 

 

M3.5

 

3.5

#6-32

#6-40

M4

 

 

 

4.2

#8-32

#8-36

 

 

M4.5

 

4.8

#10-24

#10-32

 

M5

 

 

5.5

#12-24

#12-28

M6

 

 

 

6.3

1/4-20

1/4-28

 

M8

 

M8x1

7.9

5/16-18

5/16-24

M10

 

 

M10x1.25

9.5

3/8-16

3/8-24

 

 

 

 

10.9

7/16-14

7/16-20

 

M12

 

M12x1.25

12.7

1/2-13

1/2-20

 

 

M14

M14x1.5

14.3

9/16-12

9/16-18

M16

 

 

M16x1.5

15.9

5/8-11

5/8-18

 

 

M18

M18x1.5

 

 

 

 

M20

 

M20x1.5

19.1

3/4-10

3/4-16

 

 

M22

M22x1.5

22.2

7/8-9

7/8-14

M24

 

 

M24x2

25.4

1-8

1-12

 

 

M27

M27x2

28.6

1 1/8-7

1 1/8-12

 

M30

 

M30x2

31.8

1 1/4-7

1 1/4-12

GO

CAUTION

STOP

 NOTES:  1. The most commonly strength classes for threaded fasteners are ISO 5.8, 8.8, and 10.9 specified in the  ISO 898/I standard, which correspond to the customary grades SAE 2, 5, and 8.  Other important ISO strength classes; ISO 4.6, 4.8, 9.8 and 12.9     2.  The medium thread fit 6H for nuts and 6g for screws are used in most applications. The close fit, 4g6g, is used for some set and socket screws.

    The metric coarse thread pitch is slightly smaller (finer) compared to the customary unified coarse thread pitch. For example; the metric coarse thread M8 has the thread pitch 1.25 mm and the inch thread 5/16-18 (7.94 mm) has the thread pitch 1.41 mm.

   Preferred metric sizes for thin metal flat products (sheets) in the range from 0.4 through 4 mm follow the sizes shown in TABLE 3. We used to specify even gage numbers for cold rolled material years ago, and now with the First Choice selection in the ANSI B32.100 standard, it is recommended you specify the first choice sizes or in four gage number increments.

 TABLE 3  Metal Sheet Sizes

Preferred Metric (mm)

Customary Inch

 

ANSI B32.100

 

 

 

 

 

First

Second

Third

 

Decimal

Gage

Choice

Choice

Choice

mm

Inch

Number

0.4

 

 

0.378

 0.0149

 28 Ga

 

 

0.45

0.417

 0.0164

 27 Ga 

 

0.5

 

0.455

 0.0179

 26 Ga

 

 

0.55

0.531

 0.0209

 25 Ga

0.6

 

 

0.607

 0.0239

 24 Ga

 

 

0.7

0.683

 0.0269

 23 Ga

 

0.8

 

0.759

 0.0299

 22 Ga

 

 

0.9

0.836

 0.0329

 21 Ga

1

 

 

0.912

 0.0359

 20 Ga

 

 

1.1

1.062

 0.0418

 19 Ga

 

1.2

 

1.214

 0.0478

 18 Ga

 

 

1.4

1.367

 0.0538

 17 Ga

1.6

 

 

1.519

 0.0598

 16 Ga 

 

 

1.8

1.709

 0.0673

 15 Ga 

 

2

 

1.897

 0.0747

 14 Ga 

 

 

2.2

2.278

 0.0897 

 13 Ga 

2.5

 

 

2.657

 0.1046

 12 Ga 

 

 

2.8

 

 

 

 

3

 

3.038

 0.1196

 11 Ga 

 

 

3.5

3.416

 0.1345

 10 Ga 

4

 

 

4.176

0.1644

  8 Ga 

GO

CAUTION

 

STOP

 

 

   Preferred metric, standard metric and customary inch steel plate sizes are shown in TABLE 4. It is recommended selections be made from the preferred metric column marked first and second choice. Selection of first choice sizes will further reduce the number of plate sizes from nine to five. This is a huge cost reduction compared with the 19 inch plate sizes that used to be stocked by a large USA company. Steel plate sizes shown are those specified in the ANSI B32.100 standard.

 TABLE 4  Steel Plate Sizes

Preferred Metric (mm)

 

Customary Inch

 

ASME B32.100 

 

 

First

Second

First

Second

Third

 

Choice

Choice

Choice

Choice

Choice

mm

Inch

 Inch

4

 

 

 

 

 

 

 

4.5

 

 

 

 

5

 

4.76

3/16

 

 

 

5.5

5.56

 

7/32

6

 

 

6.35

1/4

 

 

 

7, 7.5

7.14

 

9/32

 

8

 

7.9

5/16

 

 

 

9

8.73

 

11/32

10

 

 

9.5

3/8

 

 

 

 

10.3

 

13/32

 

 

11

10.9

7/16

 

 

12

 

11.9

 

15/32

 

 

 

12.7

1/2

 

 

 

14

14.3

 

9/16

 

 

15

 

 

 

16

 

 

15.9

5/8

 

 

 

18

17.5

 

11/16

 

 

 

19.1

3/4

 

 

20

 

20.6

 

13/16

 

 

22

22.2

7/8

 

 

 

 

23.8

 

15/16

25

 

 

25.4

1

 

GO

CAUTION

STOP

Preferred Tolerance Zones

   The ISO tolerance zones shown here are those specified in the ANSI B4.2 standard and tabulated in the reference material. Those shown in the green areas are those used in the preferred fits.

   The ISO System of Limits and Fits has been in use in many countries for more than 70 years.  Cold finished round bars held to the tolerance zones, h11, h9, h7 and h6, are covered in national standards throughout the world as shown in TABLE 7. GO-NOGO gages to inspect parts and reamers to produce the holes to these tolerance zones are frequently readily available. Designed software where you can enter metric or inch fit conditions, and compare them with a proven fit, has been available since 1997. A second online version was available for two years, and a new third online version will be released soon.

The ISO System of Limits and Fits offer industries in USA numerous savings opportunities. The required documentations to help cut costs in terms of engineering time, tooling and material stock has been prepared, and it is up to us to take advantage of the system. The software program, ISOTOLTM, make the limit dimensions quick to calculate and copy without errors, and can maximize those opportunities while saving time. Preferred Sizes and tolerances help reduce the number of different hole and shaft sizes used in products.

 TABLE 5  TOLERANCE ZONES FOR HOLES (ANSI B4.2)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

H1

 

JS1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

H2

 

JS2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

H3

 

JS3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

H4

 

JS4

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

G5

H5

 

JS5

K5

M5

N5

P5

R5

S5

T5

U5

V5

X5

Y5

Z5

 

 

 

 

 

 

F6

G6

H6

J6

JS6

K6

M6

N6

P6

R6

S6

T6

U6

V6

X6

Y6

Z6

 

 

 

 

D7

E7

F7

G7

H7

J7

JS7

K7

M7

N7

P7

R7

S7

T7

U7

V7

X7

Y7

Z7

 

 

 

C8

D8

E8

F8

G8

H8

J8

JS8

K8

MS

N8

P8

R8

S8

T8

U8

V8

XS

Y8

Z8

 

A9

B9

C9

D9

E9

F9

G9

H9

 

JS9

K9

M9

N9

Y9

R9

S9

T9

U9

V9

X9

Y9

Z9

 

A10

B10

C10

D10

E10

F10

G10

H10

 

JS10

K10

M10

N10

P10

R10

S10

T10

U10

V10

X10

Y10

Z10

 

A11

B11

C11

D11

E11

F11

 

H11

 

JS11

 

 

 

 

 

 

 

 

 

 

 

 

A12

B12

C12

D12

E12

 

 

H12

 

JS12

 

 

 

 

 

 

 

 

 

 

 

 

A13

B13

C13

 

 

 

 

H13

 

JS13

 

 

 

 

 

 

 

 

 

 

 

 

A14

B14

 

 

 

 

 

H14

 

JS14

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

H15

 

JS15

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

H16

 

JS16

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Legend: First choice tolerance zones are shown in green areas (ANSI B4.2 preferred)

 

             Second choice tolerance zones are shown in yellow areas (ISO 1829 selected)

 

             Third choice tolerance zones shown in read areas 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TABLE 6  TOLERANCE ZONES FOR SHAFTS (ANSI B4.2)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

h1

 

js1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

h2

 

js2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

h3

 

js3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

g4

h4

 

js4

k4

m4

n4

p4

r4

s4

t4

u4

v4

x4

y4

z4

 

 

 

 

 

 

f5

g5

h5

j5

js5

k5

m5

n5

p5

r5

s5

t5

u5

v5

x5

y5

z5

 

 

 

 

 

e6

f6

g6

h6

j6

js6

k6

m6

n6

p6

r6

s6

t6

u6

v6

x6

y6

z6

 

 

 

 

d7

e7

f7

g7

h7

j7

js7

k7

m7

n7

p7

r7

s7

t7

u7

v7

x7

y7

z7

 

 

 

c8

d8

e8

f8

g8

h8

 

js8

k8

m8

n8

p8

r8

s8

t8

u8

v8

x8

y8

z8

 

a9

b9

c9

d9

e9

f9

g9

h9

 

js9

k9

m9

n9

p9

r9

s9

t9

u9

v9

x9

y9

z9

 

a10

b10

c10

d10

e10

f10

 

h10

 

js10

 

 

 

 

 

 

 

 

 

 

 

 

 

a11

b11

c11

d11

e11

 

 

h11

 

js11

 

 

 

 

 

 

 

 

 

 

 

 

 

a12

b12

c12

d12

 

 

 

h12

 

js12

 

 

 

 

 

 

 

 

 

 

 

 

 

a13

b13

c13

 

 

 

 

h13

 

js13

 

 

 

 

 

 

 

 

 

 

 

 

 

a14

b14

 

 

 

 

 

h14

 

js14

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

h15

 

js15

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

h16

 

js16

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Legend: First choice tolerance zones are shown in green areas (ANSI B4.2 preferred)

 

             Second choice tolerance zones are shown in yellow areas (ISO 1829 selected)

 

             Third choice tolerance zones shown in read areas 

 

 

 

 

 

   Hole basis fits with hole tolerances H11, H9, H8 and H7 help rationalize on standard cutting tools and gages, whereas shaft basis fits with shaft tolerances h11, h9, h7 and h6 help rationalize on standard round steel bars available in all major industrial countries. The ANSI B32.100 standard specify the above shaft tolerances and diameters, and the sizes are according to those shown in TABLE 1.  How the tolerance zones apply in national standards are shown in TABLE 7 below.

  TABLE 7  Round Cold Finished Steel Bars

Country

National Standard

ISO Product Tolerance

 

Other ISO Shaft Tolerances

Global

ISO 683-18

h11

h9

h7

h6

H12, h10, h8 

USA

ANSI B32.100

h11

h9

h7

h6

  

Japan

JIS G3123

h11

h9

h7

h6

h13, h12, h10, h8

Germany

DIN EN 10278

h11

h9

h7

h6

H12, h10, h8 

France

NF EN 10278

h11

h9

h7

h6

H12, h10, h8 

Italy

UNI EN 10278

h11

h9

h7

h6

H12, h10, h8 

UK

BS EN 10278

h11

h9

h7

h6

H12, h10, h8 

Australia

AS 1654*

h11

h9

h7

H6

 

 

 

GO

CAUTION

*This is a preferred tolerance standard and not a steel product standard

Ten Preferred Hole and Shaft Basis Fits

   The ANSI standard and software have ten preferred hole and shaft basis fits ranging from LOOSE RUNNING to FORCE fits as shown in TABLE 8.  It is recommended you use hole basis fits in most applications since it helps you reduce the cost of cutting tools and gages.  However, it may be to your advantage to use shaft basis fits where you have a standard shaft size in a machine with bearings, couplings, sprockets, gears, and other components attached to it.    Examples include knitting, printing, and farm machines. Each preferred fit has the same clearance or interference for hole or shaft basis fit listed on the same line. The UK and Australian standards shown above also have ten hole and shaft basis fits, but the fit H9/d9 and D9/h9 has replaced the H9/d10 and D10/h9.  Input from the automotive industries in USA demanded we add the interference fit H7/u6 and U7/h6 to the ANSI B4.2 standard. We combined two clearance fits into one, and ended up with the ten Preferred Fits as shown below but with the same hole (H11, H9, H8 and H7) and shaft (h11, h9, h7 and h6) tolerance zones:

 TABLE 8  Preferred Fits (ANSI B4.2)

 

ISO SYMBOL

DESCRIPTION

 

 

Hole

Shaft

 

 

Basis

Basis

 

 

H11/c11

C11/h11

Loose running fit for wide commercial tolerances or allowances

 

 

 

 

on external members.

 More

 

H9/d9

D9/h9

Free running fit not for use where accuracy is essential, but good for large

 Clearance

Clearance

 

 

temperature variations, high running speeds, or heavy journal pressures.

 

 

H8/f7

F8/h7

Close running fit for running on accurate machines and for accurate

 

 Fits

 

 

location at moderate speeds and journal pressures.

 

 

H7/g6

G7/h6

Sliding fit not intended to run freely, but to move and turn freely

 

 

 

 

and locate accurately.

 

 

H7/h6

H7/h6

Locational clearance fit provides snug fit for locating stationary parts;

 

 

 

 

 but can be freely assembled and disassembled.

 

Transition 

H7/k6

K7/h6

Locational transition fit for accurate location, a compromise

 

 

 

 

between clearance and interference.

 

Fits

H7/n6

N7/h6

Locational transition fit for more accurate location where

 

 

 

 

greater interference is permissible.

 

 

H7/p61

P7/h6

Locational interference fit for parts requiring rigidity and alignment with

 

 

 

 

prime accuracy of location but without special bore pressure requirements.

 

Interference

H7/s6

S7/h6

Medium drive fit for ordinary steel parts or shrink fits on light sections, the

 

 

 

 

tightest fit usable with cast iron.

 More

Fits

H7/u6

U7/h6

Force fit suitable for parts which can be highly stressed or for shrink fits where the heavy pressing forces required are impractical.

 Interference

 

GO 

CAUTION 

 

 

1Transition fit for basic sizes in range from 0 through 3 mm.

Source: Kverneland, Knut O: “METRIC STANDARDS for Worldwide Manufacturing” published by GOmetricUSA.org (ASME Press) 2012 Electronic (2007 Print) 800p 500 tables ISBN: 0974447773 (0791802612)

References:

Kverneland, Knut O:  METRIC STANDARDS for Worldwide Manufacturing” published by GOmetricUSA.org (ASME Press) 2012 Electronic (2007 Print) 800p 500 tables ISBN: 0974447773 (0791802612)

ANSI B4.2-1978 Preferred Metric Limits and Fits

ANSI B32.100-2005 Preferred Metric Sizes for Flat, Round, Square, Rectangular, and Hexagonal Metal Products

How It All Started  

The book, METRIC STANDARDS for Worldwide Manufacturing (800 pages, 500 tables, see: www.GOmetricUSA.org or www.kok.com for more details) was developed over more than 40 years of hard work and sometimes struggles. The participation during 1972 and 1973 as the Massey Ferguson member of an ad hoc metric study committee of the Society of Automotive Engineers (SAE) Off-Road Vehicle Council with members from the other farm machine producers such as John Deere, Caterpillar, Clark, Case, International Harvester, etc. gave me the idea to author the book. The first positive break came when the Past Director of Engineering Standards (Past President of ANSI) for General Motors endorsed the project and made it possible to use International Organization for Standardization (ISO),  American Society of Mechanical Engineers (ASME)  and Industrial Fasteners Institute (IFI) standards in the proposed publication. He also nominated me to chair the ANSI B4 committee on Limits and Fits, and we drafted and published several standards.  The most important one, ANSI B4.2-1978 Preferred Metric Limits and Fits, became an important part of my publishing efforts.  The ISO tolerance software  (ISOTOLTM ) was also developed and published in agreement with the above standard.  Later the ANSI B32.100-2005 Preferred Metric Sizes for Flat, Round, Square, Rectangular, and Hexagonal Metal Products was also drafted by me.  The preferred sizes and tolerance zones, h11, h9, h7 and h6, covered in the ANSI B4.2 standard are also covered in the new metal products standard, which are standard tolerances for round material stock in all major industrial countries in the world. At that time, I worked for the global company, Massey Ferguson in Detroit, and they were also very much interested in me developing drafting and engineering standards to be used in their worldwide engineering and manufacturing operations.

World Metric Standards for Engineering was published by Industrial Press in New York 1978.  It sold in the thousands of copies around the world. The publishing company was not interested to publish my proposed second edition since ASME required royalty payments for use of their standards. The result was I worked out an agreement with ASME Press to publish the book. The title was changed to METRIC STANDARDS for Worldwide Manufacturing, and the second edition of the book was published in 1996.

In 2002 I proposed to publish an electronic version of the book. At that time, ASME Press, had no interest in helping me publish the e-book, but they gave me permission to publish it on my own.  The third edition of the metric handbook was published in 2003 and distributed by the American National Standards Institute (ANSI) Electronic Standards Store .  Many companies now make the e-book available on multiple work stations over their Intranet.  Each year a new updated edition was published and the seventh edition in 2007.  ASME Press decided to publish a hard copy of the book directly from my electronic 2007 edition, and in 2010 they market the e-book (2007 version). Customers may now buy the electronic (2012 version) or the paperback (2007 version) from me using most credit cards or PayPal. See the Order Form.

Industry Users of METRIC STANDARDS Book, Software or Consulting Services

  1. "The METRIC STANDARDS for Worldwide Manufacturing  book is recommended used in every machine shop and design office converting to the metric system of measure".  Stan Jakuba,  Metrication Consultant, e-mail jakubast at gmail.com, phone 860 521 7924
     
  2. "The METRIC STANDARDS for Worldwide Manufacturing  book is an essential tool for any operation involved in the business of engineering and manufacturing of products in compliance with world standards and the international marketplace".  - Lowell Foster, Technology Concepts and Engineering Int, e-mail  lofosgdt at minn.net, phone 612 722 9115
  3. I think the ISOTOLTM software is an excellent tool  for analyzing and harmonizing fits and tolerances of metric and inch designs.  It's a real timesaver because it minimizes errors when looking up numbers repeatedly in the ISO tables.   Mike E Yamat myamat at cooperpower.com; Phone 414 768 8303; Fax 414 768 8236 (User of metric book and software) Cooper Power Systems, 2800 9th Ave, S Milwaukee WI 53172

  4.  Rick wrote the following about the computer program; "ISOTOLTM interfaces just fine with AutoCAD. The software works just fine with all MS Windows versions and MDT. It is straight forward and easy to use. It is a simple program that would be of great value to anyone that needs to figure tolerancing".  Rick Novara ricknovara at compuserve.com; Phone 704 921 0303; Fax 704 921 0304, Novara Engineering, 12325 Mallard Ridge Drive, Charlotte NC 28269.

The 2012 Electronic 8th Edition of METRIC STANDARDS for Worldwide Manufacturing or hard copy (2007 edition) ASME Press, 800 pages, 500 tables. Do you need help with bringing your business in tune with Global Manufacturing and Engineering? Contact Knut, and I shall be happy to help you (See Consulting Services). The new ISOTOLTM Computer Tolerance Software provides the powerful tool you need to help cut costs in  manufacturing and engineering.  

GO metricUSATM.org, Inc. 318 St Andrews Road Statesville NC 28625-4659 USA, E-mail kok at GOmetricUSA.org  Phone 704 990 8449


How the ISO Tolerance System can help Cut Manufacturing and Engineering Costs

ISOTOLTM on ISO Tolerances

Last modified: 2012-10-21

ISO tolerance standards offer industry a savings opportunity. New software program, ISOTOLTM  make those standards more easily available and can maximize those opportunities while saving time. Preferred Metric Sizes and tolerances helps reduce the number of hole and shaft sizes specified.

Ten preferred hole basis fits with hole tolerances identified by ASME B4.2 as holes H11, H9, H8 and H7 help rationalize on standard cutting tools and gages, whereas the ten preferred shaft basis fits with shaft tolerances h11, h9, h7 and h6 help rationalize on standard round steel bars available in all major industrial countries. The new ASME B32.100-2005 standard specify the above shaft tolerances. See the 2012 editions of the METRIC STANDARDS  for Worldwide Manufacturing  for the American standard sizes and tolerances.  The ASME standard and software show ten preferred hole and shaft basis fits ranging from LOOSE RUNNING to FORCE fits.  Each hole basis fit has a corresponding shaft basis fit with the same clearance or interference.

The system needs no particular CAD software. Users still must use standard hole or shaft sizes in order to save in manufacturing. Engineers in the EU countries have taken advantage of the system for over 70 years, and many users there still use published tables or recall the allowances from memory.

The ASME B4.2 standard shows tables of allowances for the ISO tolerance zones, and limit dimensions for the preferred fits and sizes. In the USA, these tables are published in the Machinery's Handbook and the METRIC STANDARDS  for Worldwide Manufacturing books.

Time spent searching tables and trying to understand the system will be saved by using the two programs. You also save time comparing the new metric fits with the old customary inch fits, and you can quickly modify proposed fits to give similar conditions as those proven in use. For more information about the ISO tolerance system and CD, just enter one of the following web page on the Internet.

The ISOTOLTM  Computer Tolerance Software provides the powerful tool you need to cut costs in manufacturing and engineering.

International Date Inscription

All numeric ISO date and military time inscriptions

Last modified: 2012-10-21  

The all-numeric writing of dates varies in different parts of the world.  The date April 2, 2012 is written as follows:

Global ISO 8601           :     2012-04-02     or   YEAR-MONTH-DAY

North America              :       4-2-2012          or    MONTH-DAY-YEAR

Traditional Europe (EU) :     2-4-2012          or     DAY-MONTH-YEAR.  EU has now adopted use of the ISO standard, and released the European Norm EN 28601. 

We in USA use MONTH-DAY-YEAR date system.  The Europeans have used   DAY-MONTH-YEAR on all numeric dates. It is relatively easy for us to switch, since we are used to the month-day sequence.  Having worked for multinational companies, this could cause costly mistakes.  I just translated a contract where the USA parties misunderstood the German date by 6 months.

EU and many other countries have now adopted the ISO 8601 standard sequence of   YEAR-MONTH-DAY for all numeric dates.

The military 24 hour time designation is used throughout the world.  Many countries do not have nor use the AM and PM designations in their language.  To be specific,  such as in airline, bus or train schedules, the 24 hour time designation is used.  For example the time 1:30 PM  has the international or military inscription as follows; 13:30.

The MS Windows 8, 7, XP, 2000, NT, 98 or 95 has settings for the ISO date and 24 hour time designations.

Copyright © 2012 GO metricUSATM.org, Inc.  Last modified: 2012-10-21

News

Relevant news stories related to the advancement and implmentation of metric system in the USA.

Site lauch: 2011-01-19 The official launch of the web site for http://www.GOmetricUSA.org. The first METRIC HOME page; http://www.kok.com was published more than 20 years ago.