UNITED STATES DEPARTMENT OF COMMERCE

BUREAU OF STANDARDS

AMERICAN NATIONAL

SCREW THREAD TABLES

FOR SHOP USE

II. Special Threads

MISCELLANEOUS PUBLICATION OF THE BUREAU OF STANDARDS, No. 99

ERRATA

B. S. Mi so . Pub. No. 99-

Page Table Column

Line

(below

heading)

Incorrect

value

v.Jorrect

value

k

5

g

10

SS

gg

27

2g

29

d

4-th

5 th

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2

12

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20

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• 0179

UNITED STATES DEPARTMENT OF COMMERCE

R. P. LAMONT, Secretary

BUREAU OF STANDARDS

GEORGE K. BURGESS, Director

MISCELLANEOUS PUBLICATION OF THE BUREAU OF STANDARDS, No. 99 AMERICAN NATIONAL

SCREW THREAD TABLES

FOR SHOP USE

IL Special Threads

[Recommended Commercial Standard]

SEPTEMBER 24, 1929

UNITED STATES

GOVERNMENT PRINTING OFFICE

WASHINGTON : 1929

For sale by the Superintendent of Documents, Washington, D. C. Price 10 cents

AMERICAN NATIONAL SCREW-THREAD TABLES FOR SHOP USE

II. SPECIAL THREADS

ABSTRACT

This publication presents in compact form the tables of dimensions of special screw threads having the American National form of thread (60°), as published in the 1928 Report of the National Screw Thread Commission (Sees. IV and XD), Bureau of Standards Miscellaneous Publication, No. 89. 1 These tables cover the

basic sizes, limiting dimensions, and tolerances for the American National 12-pitch thread series and other screw threads of special diameters, pitches, and lengths of engangement.

CONTENTS

Page

I. American National 12-pitch thread series 1 Table 87. American National 12-pitch thread series 3 Table 88. Limiting dimensions and tolerances, classes 1, 2, 3, and 4 fits, American National

12-pitch thread series 4

II. Screw threads of special diameters, pitches, and lengths of engagement 7 Table 27. Thread dimensions of special screw threads, classes 1, 2, 3, and 4 fits 8 Table 28. Pitch diameter tolerances for special screw threads, class 1, loose fit 9 Table 29. Pitch diameter tolerances for special screw threads, class 2, free fit___ 12 Table 30. Pitch diameter tolerances for special screw threads, class 3, medium fit 15 Table 31. Pitch diameter tolerances for special screw threads, class 4, close fit 18

I. AMERICAN NATIONAL 12-PITCH THREAD SERIES

Where special threads are required, it is sometimes essential to select a certain pitch as standard for a range of sizes. Also, in general practice, where the pitch of a special thread is optional, the uniform use of a selected pitch is advantageous. For such applications the 12 pitch

is widely used, particularly for two distinct purposes as given below, but for different reasons.

Sizes of 12-pitch threads from one-half inch to and including 1% inches are used in railroad

practice, which requires that worn stud holes be retapped with a tap of the next larger size, the

increment being one-sixteenth inch throughout most of the range.

The 12-pitch threads are also widely used in machine construction, as for thin nuts on

shafts and sleeves. From the standpoints of good design and simplification of practice, it is desirable to maintain shoulder diameters to one-eighth-inch steps. The 12 pitch is the coarsest,

for a thread of basic depth, which will permit a threaded collar which screws onto a threaded

shoulder to slip over a shaft, the difference in diameter between shoulder and shaft being

one-eighth inch.

1 The complete report may be procured from the Superintendent of Documents, U. S. Government Printing

Office, Washington, D. C, at 50 cents per copy.

1
NATIONAL SCREW THREAD COMMISSION —P +• P

Note—No allowance is shown, mum screw are basic.

Fig. 3.

American National form of thread

This condition exists in class 2, free fit, and class 3, medium fit, where both the minimum nut and the maxin= number of threads per inch H=0.866025 p, depth of 60° sharp v thread h=0.649519 p, depth of American National form of thread %h=0.541266 p, maximum depth of engagement

.F= 0.125000 p, width of flat at crest and root of American National form /= 0.108253 pi = HH J-depth of truncation

Meav/L/*£ Shows

Fig. 10.

Illustration of tolerances and crest clearances for class 3, medium fit
DIMENSIONS OF SPECIAL SCREW THREADS

Table 87.American National 1%-pitch thread series

3

Identification

Threads per inch

Basic diameters

Major

diameter

Pitch diameter Minor

diameter K

Metric equivalent of major

diameter

Y2-- 9U 1

. %-

%-

lKe1/s 2 m.

IK 2

l%.

1/2 2 1%.

2__.

Wy

2%.

3__.

12

1212

12

1212

12

12

12

12

12

121212

1212

12

12

12

1212

12

Inches

0. 5000

. 5625

. 6250

. 6875

. 7500

. 8125

. 8750

. 9375

1. 0000

1. 0625

1. 1250

1. 1875

1. 2500

1. 3125

1. 3750

1. 5000

1. 7500

2. 0000

2. 2500

2. 5000

2. 7500

3. 0000

Inches

0. 4459

. 5084

. 5709

. 6334

. 6959

. 7584

. 8209

. 8834

. 9459

1. 0084

1. 0709

1. 1334

1. 1959

1. 2584

1. 3209

1. 4459

1. 6959

1. 9459

2. 1959

2. 4459

2. 6959

2. 9459

Inches

0. 3917

. 4542

. 5167

. 5792

. 6417

.7042

. 7667

. 8292

. 8917

. 9542 0167

0792

1417 2042

1. 2667

1. 3917

1. 6417

1. 8917

2. 1417

2. 3917

2. 6417

2. 8917

1 Standard size of the American National coarse-thread series.

2 Standard size of the American National fine-thread series.
4 NATIONAL SCREW THREAD COMMISSION

Table 88.

Limiting dimensions and tolerances, classes 1,2,3, and Jj-fits, American National 12-pitch thread series

Dimensions and tolerances

1 BOLTS AND SCREWS

[Max__

Class 1. major diameter \ Min__

lTol._.

Classes 2, 3, and 4, major

diameter

| rp Qj Class 1, minor diameter. _ Max.4 Classes 2, 3, and 4, minor diameter Max.4 __

Class 1, loose fit, pitch, di- {JJfn ameter, (t61.II

Class 2, free fit, pitch di- f ]^f*"

ameter |to1

~

Class 3, medium fit, pitch f^f*"

diameter [Tol

~~

Class 4, close fit, pitch di- f j^f*"

ameter

I Tol

NUTS AND TAPPED HOLES

Classes 1, 2, 3, and 4, major di- ameter „ Min.5 _ _

Classes 1, 2, 3, and 4, minor f JJf

X_ " diameter

| To^n " ~

Classes 1, 2, 3, and 4, pitch di- ameter Min_ _ Class 1, pitch diameter {toT"

Class 2, pitch diameter {xoT*""

Class 3, pitch diameter {toI*"

Class 4, pitch diameter

Size, (inches)

Inch

0. 4976

. 4818

. 0158

. 5000

. 4888

. 0112

.3954

.3978

.4435

. 4356

. 0079

. 4459

. 4403

. 0056

. 4459

. 4419

. 0040

. 4464

. 4444

. 0020

5000

4225

4098

0127

. 4459

. 4538

. 0079

. 4515

. 0056

. 4499

. 0040

. 4479

. 0020

Inch

0. 5601

. 5443

. 0158

. 5625

. 5513

. 0112

. 4579

. 4603

. 5060

. 4981

. 0079

. 5084

. 5028

. 0056

. 5084

. 5044

. 0040

. 5089

. 5069

. 0020

5625

4850

4723

0127

5084

5163 0079

5140

0056

5124

0040

5104

0020

Inch

0. 6226

. 6068

. 0158

. 6250

. 6138

. 0112

. 5204

. 5228

. 5685

. 5606

. 0079

. 5709

. 5653

. 0056

. 5709

. 5669

. 0040

. 5714

. 5694

. 0020

6250

5438

5348

0090

5709

5788

0079

5765

0056

5749

0040

5729

0020

Inch

0. 6851

. 6693

. 0158

. 6875

. 6763

. 0112

. 5829

. 5853

. 6310

. 6231 .0079

. 6334

. 6278

. 0056

. 6334

. 6294

. 0040

. 6339

. 6319

. 0020

6875

6063

5973 0090

6334

6413

0079

6390

0056

6374

0040

6354

0020

. Inch

0. 7476

. 7318

. 0158

. 7500

. 7388

. 0112

. 6454

. 6478

. 6935

. 6856

. 0079

. 6959

. 6903

. 0056

. 6959

. 6919

. 0040

. 6964

. 6944

. 0020

7500

6688

6598

0090

6959

7038

0079

7015

0056

6999

0040

6979

0020

Inch

0. 8101

. 7493

. 0158

. 8125

. 8013

. 0112

. 7079

. 7103

. 7560

. 7481

. 0079

. 7584

. 7528

. 0056

. 7584

. 7544

. 0040

. 7589

. 7569

. 0020

. 8125

. 7313

. 7223

. 0090

7584

7663

0079

7640

0056

7624

0040

7604

0020

Inch

0. 8726

. 8568

. 0158

. 8750

. 8638

. 0112

. 7704

.7728

. 8185

. 8106

. 0079

. 8209

. 8153

. 0056

. 8209

. 8169

. 0040

. 8214

. 8194

. 0020

8750

7938

7848

0090

8209

8288

0079

8265

0056

8249

0040

8229

0020

Footnotes at end of table.
DIMENSIONS OF SPECIAL SCREW THREADS 5

Table 88.Limiting dimensions and tolerances, classes 1, 2, 3, and 4 fits, American National 12-pitch thread

series—Continued

Dimensions and tolerances 1

1 BOLTS AND SCREWS

[Max..

Class 1, major diameter |Min__

^Tol_._

[Max__

Classes 2, 3, and 4, major diameter J Min_ _ 1To1___

Class 1, minor diameter Max*..

Classes 2, 3, and 4, minor diameter. _ Max 4 __ [Max__

Class 1, loose fit, pitch diameter \ Min__

(Tol___

(Max..

Class 2, free fit, pitch diameter { Min__

|Tol___

(Max..

Class 3, medium fit, pitch diameter. A Min_ _ [Tol___

[Max__

Class 4, close fit, pitch diameter { Min__

(Tol___

NUTS AND TAPPED HOLES

Classes 1, 2, 3, and 4, major diameter. _Min.5 _ [Max..

Classes 1, 2, 3, and 4, minor diameterJ Min_ _ iTol___

Classes 1, 2, 3, and 4, pitch diameter. _ Min __ Class 1, pitch diameter -{toT^"

Class 2, pitch diameter I'M*

-

Class 3, pitch diameter "{toT"

Class 4, pitch diameter {toT"~

Size, (inches)

1 m 3 13/16 IK 3 Me m

10 11 13 14 15 16

Inch

0. 9976

. 9818

. 0158

Inches

1. 0601

1. 0443

. 0158

Inches

1. 1226

1. 1068

. 0158

Inches

1. 1851

1. 1693

. 0158

Inches

1. 2476

1. 2318

. 0158

Inches

1. 3101

1. 2943

. 0158

Inches

1. 3726

1. 3568

. 0158

1. 0000

. 9888

. 0112

1. 0625

1. 0513

. 0112

1. 1250

1. 1138

. 0112

1. 1875

1. 1763

. 0112

1. 2500

1. 2388

. 0112

1. 3125

1. 3013

. 0112

1. 3750

1. 3638

. 0112

. 8954

. 8978

. 9579

. 9603

1. 0204

1. 0228

1. 0829

1. 0853

1. 1454

1. 1478

1. 2079

1. 2103

1. 2704

1. 2728

. 9435

. 9356

. 0079

1. 0060

. 9981

. 0079

1. 0685

1. 0606

. 0079

1. 1310

1. 1231

. 0079

1. 1935

1. 1856 .0079

1. 2560

1. 2481

. 0079

1. 3185

1. 3106

.0079

. 9459

. 9403

. 0056

1. 0084

1. 0028

.0056

1. 0709

1. 0653

. 0056

1. 1334

1. 1278

. 0056

1. 1959

1. 1903 .0056

1. 2584

1. 2528

.0056

1.3 09

1. 3153

.0056

. 9459

. 9419

. 0040

1. 0084

1. 0044

. 0040

1. 0709

1. 0669

. 0040

1. 1334

1. 1294

. 0040

1. 1959

1. 1919

. 0040

1. 2584

1. 2544

. 0040

1. 3209

1. 3169

. 0040

. 9464

. 9444

. 0020

1. 0089

1. 0069

. 0020

1. 0714

1. 0694

. 0020

1. 1339

1. 1319

. 0020

1. 1964

1. 1944

. 0020

1. 2589

1. 2569

. 0020

1. 3214

1. 3194

. 0020

1. 0000 1. 0625 1. 1250 1. 1875 1. 2500 1. 3125 1. 3750

. 9188

. 9098

. 0090

. 9813

. 9723

. 0090

1. 0438

1. 0348

. 0090

1. 1063

1. 0973

.0090

1. 1688

1. 1598

. 0090

1. 2313

1. 2223

. 0090

1. 2938

1. 2848

. 0090

. 9459 1. 0084 1. 0709 1. 1334 1. 1959 1. 2584 1. 3209

. Q^38 yooo

. 0079

1. UIOO

. 0079

1. Ul Co

. 0079

1 1 4.1 3 .00791 9038

. 0079

1 9AAQ

. 0079

1 Q988

. 0079

. 9515

. 0056

1. 0140

. 0056

1. 0765

. 0056

1. 1390

. 0056

1. 2015

. 0056

1. 2640

. 0056

1. 3265

. 0056

. 9499

. 0040

1. 0124

. 0040

1. 0749

. 0040

1. 1374

. 0040

1. 1999

. 0040

1. 2624

. 0040

1. 3249

. 0040

. 9479

. 0020

1. 0104

. 0020

1. 0729

. 0020

1. 1354

. 0020

1. 1979

. 0020

1. 2604

. 0020

1. 3229

. 0020

Footnotes at end of table.
6 NATIONAL SCREW THREAD COMMISSION

Table 88.

Limiting dimensions and tolerances, classes 1,2, 8, and 4 fits, American National 12-pitch thread

series—Continued

Dimensions and tolerances

Size, (inches)

18 19

2H

20

2H

28 BOLTS AND SCREWS

[Max..

Class 1, major diameter ^Min_.

[Tol...

fMax_.

Classes 2, 3, and 4, major diameter. A Min_.

(Tol... Class 1, minor diameter Max.4 _. Classes 2, 3, and 4, minor diameter. .Max.4 ..

Class 1, loose fit, pitch diameter.

Class 2, free fit, pitch diameter.

Max..

Min_.

Tol... Max..

Min_.

Tol... [Max..

Class 3, medium fit, pitch diameter. _] Min_

(Tol... [Max..

Class 4, close fit, pitch diameter ^Min_.

|Tol__.

NUTS AND TAPPED HOLES

Classes 1, 2, 3, and 4, major diameter_Min.5 _. [Max..

Classes 1, 2, 3, and 4, minor diameterJ Min.

[Tol... Classes 1, 2, 3, and 4, pitch diameter. _ Min__

Class 1, pitch diameter {toT^"

Class 2, pitch diameter {to}*'

Class 3, pitch diameter {toT"

Class 4, pitch diameter -{toT"

Inches

1. 4976

1. 4818

. 0158

1. 5000

1. 4888

.0112

1. 3954

1. 3978

1. 4435

1. 4356

. 0079

1. 4459

1. 4403

. 0056

1. 4459

1. 4419

. 0040

1. 4464

1. 4444

. 0020

1. 5000

1. 4188

1. 4098

.0090

1. 4459

1. 4538

.0079

1. 4515

.0056

1. 4499

. 0040

1. 4479

. 0020

Inches

1. 7476

1. 7318

. 0158

1. 7500

1. 7388

. 0112

1. 6454

1. 6478

1. 6935

1. 6829

. 0106

1. 6959

1. 6882

.0077

1. 6959

1. 6896

. 0063

1. 6964

1. 6933

. 0031

1. 7500

Inches

1. 9976

1. 9818

. 0158

2.0000

1. 9888

. 0112

Inches

2. 2476

2. 2318

.0158

8954

8978

1

1. 6598

.0090

1. 6959

1. 7065

.0106

1. 7036

. 0077

1. 7022

.0063

1. 6990

. 0031

1. 9435

1. 9329

. 0106

1. 9459

1. 9382

. 0077

1. 9459

1. 9396

. 0063

1. 9464

1. 9433

. 0031

2. 0000

1. 9188

1. 9098

. 0090

1. 9459

1. 9565

.0106

1. 9536

. 0077

1. 9522

.0063

1. 9490

.0031

2500

2388

0112

2. 1454

2. 1478

2. 1935

2. 1823

. 0112

2. 1959

2. 1876

. 0083

2. 1959

2. 1890

. 0069

2. 1964

2. 1930

. 0034

2. 2500

2. 1688

2. 1598

. 0090

2. 1959

2. 2071 .0112

2. 2042

.0083

2. 2028

i

. 0069

2. 1993

. 0034

Inches

2. 4976

2. 4818

. 0158

2. 5000

2. 4888

. 0112

2. 3954

2. 3978

2. 4435

2. 4323

.0112

2. 4459

2. 4376

.0083

2. 4459

2. 4390

. 0069

2. 4464

2. 4430

. 0034

2. 5000

2. 4188

2. 4098

.0090

2. 4459

2. 4571

.0112

2. 4542

.0083

2. 4528

.0069

2. 4493

. 0034

Inches

2. 7476

2. 7318

.0158

7500

7388

0112

2. 6454

2. 6478

2. 6935

2. 6823

. 0112

2. 6969

2. 6876

.0083

2. 6959

2. 6890

. 0069

2. 6964

2. 6930

.0034

2. 7500

2. 6688

2. 6598

.0090

2. 6959

2. 7071 .0112

2. 7042

.0083

2. 7028

. 0069

2. 6993

. 0034

Inches

2. 9976

2. 9818

. 0158

3. 0000

2. 9888

.0112

2. 8954

2. 8978

2. 9435

2. 9323

.0112

2. 9459

2. 9376

.0083

2. 9459

2. 9390

.0069

2. 9464

2. 9430

. 0034

3. 0000

2. 9188

2. 9096

.0090

2. 9459

2. 9571 .0112

2. 9542

.0083

2. 9528

.0069

2. 9493

.0034

1 Tolerances are based on a length of engagement of 1 inch.

3 Standard size screw and nut of the American national coarse-thread series.

8 Standard size screw and nut of the American national fine-thread series.

4 Dimensions given for the maximum minor diameter of the screw are figured to the intersection of the worn

tool arc with a center line through crest and root. The minimum minor diameter of the screw shall be that cor- responding to a fiat at the minor diameter of the minimum screw equal to YsXp, and may be determined by- subtracting 0.0541 inch from the minimum pitch diameter of the screw.

5 Dimensions for the minimum major diameter of the nut correspond to the basic flat, (Y&Xp), and the

profile at the major diameter produced by a worn tool must not fall below the basic outline. The maximum

major diameter of the nut shall be that corresponding to a flat at the major diameter of the maximum nut equal

to jiiXp, and may be determined by adding 0.0662 inch to the maximum pitch diameter of the nut.
DIMENSIONS .OF SPECIAL SCREW THREADS 7

II. SCREW THREADS OF SPECIAL DIAMETERS, PITCHES, AND LENGTHS OF

ENGAGEMENT

For threaded parts such as hub and radiator caps in the automotive industry, threaded

collars on machine tools, etc., where the diameters are larger, the pitches finer, and the lengths

of engagement shorter than for bolt and nut practice Tables 27, 28, 29, 30, and 31 are ar- ranged herein, and are intended to cover all practical combinations of diameter, pitch, length

of engagement, and class of fit. The use of these tables instead of the application of formulas

to determine limiting dimensions of a special thread facilitates placing dimensions on drawings. Also, in cases of special threads of the same diameter, pitch, and class of fit, but

slightly different lengths of engagement, the threads may be gaged by a single set of gages, as identical pitch diameter tolerances will be applied.

Rules for Use of Tables.—For consistent application of these pitch-diameter tolerance

tables to all cases, adherence to the following rules relative to the use of the tables is necessary:

1. All thread dimensions of threads of special diameters, pitches, and lengths of engagement, except pitch diameter tolerances, are derived from Table 27. Pitch diameter tolerances

are taken from Tables 28, 29, 30, and 31, depending upon the class of fit required.

Tolerances on pitch diameter corresponding to major diameters between those for which

values are given in the tables shall be those of the next larger diameter.

2. Tolerances on pitch diameter for pitches between those for which values are given in

the tables shall be those of the next coarser pitch, except that for screws having 80, 72, 44, 13,

11, 9, 7, 5, or 4:}i threads per inch, lengths of engagement of one and one-half diameters or less, and diameters less than the standard diameters for the respective pitches as given in Section

III 2 for standard sizes and pitches, the tolerances given in Section III shall be used

3. Tolerances on pitch diameter for pitches coarser than 4 threads per inch shall be the same as those for 4 threads per inch.

4. Tolerances on pitch diameter when the length of engagement is y2} or IK, inches for 12 threads per inch and finer, or 1, or 3, inches for pitches coarser than 12 threads per inch, shall correspond to the interval of which these are the upper limits.

5. Tolerances on pitch diameter for lengths of engagement greater than those for which

values are given shall be the maximum values listed for the pitch concerned.

Example: 3% inch, 16-thread, class 1, with allowance on screw, one-half inch length of

engagement

From Table 28: Pitch diameter tolerance =0. 0095

Also from Table 27, for the screw: Maximum major diameter =3. 2500 —0. 0018=3. 2482

Minimum major diameter =3. 2482— . 0126 = 3. 2356

Maximum minor diameter =3. 2500— . 0785 =3. 1715 Maximum pitch diameter =3. 2500— . 0424 =3. 2076

Minimum pitch diameter =3. 2076- . 0095 = 3. 1981 And for the nut: Minimum major diameter =3. 2500

Minimum minor diameter =3. 2500— . 0677=3. 1823 Maximum minor diameter =3. 1823+ . 0068 =3. 1891 Minimum pitch diameter =3. 2500- . 0406 =3. 2094

Maximum pitch diameter =3. 2094+ . 0095 = 3. 2189

2 Of the 1928 report. 61053°—29 2
8 NATIONAL SCEEW THREAD COMMISSION

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. . . . . o

Tfrl O TH 00 O iO CM CM CO Tfr lO CO OOOO

00 iCN CO

as 00 os ^ CO t> 00 o OOOrH

10 co 00 co

CM lO O rH

t-h t-h CM CO O ^ CO o 00 O rH rH rH rH rH £00000 •—H o

tHOOOCM O CO CO CM

CM CM CM CO OOOO

00 CM O CO

to O CO CO COtH^uO OOOO

tO T-H O t-H o 00 o o OOt-Ht-H

rH CO tO CM O r-s£ O rH CO CO 00

<U rH rH rH rH rH SOOOOO '—H o

CO CM rH IO O CO J> CM CM CM CM CO OOOO

t-H CO rH t-H CO O CO-* CO^^iO OOOO

O CM CO ^ lO t-H 00 CM CO 00 O CO O O t-H rH

00 TjH CM rH O CM -si-l t- OS W t-H rH rH rH rH

K£00000 -l o

t-H 00-*

CM CM CM CO OOOO

WTtHOtO

CM 00 CO CO •* -* tO OOOO

00 CO t— 00 1> -* CM 00 c© 00 t-h CO OOHH

OOO^JH 000

-si CO tJH -* xo ^00000 £00000 ^

o

-* CM CO CM tO CO CO l> OOOO

CM O 00 CM 00 OS OS t-H O O O t-h OOOO00 CM CM O CM to O 00

rH t-h CM CM OOOO

CM CO CM 00 CM

tO tO CO CO 1> ^OOOOO £000 00

CO O CM CM

S>> 00 OS o

O O O t-h OOOO

CM O 00

00 CM OS O t-h CM CM tH OOOO

OOOOO ^OOOOO 3-200000 £00000 . . . . o

OOOO

OOOO OOOO

OOOO OOOO

l> 00 OS O t-h

-«£ O O O rH t-H "OOOOO £00000

t-h (N CO to O O O 1

!

CO 00 t-H TiH

t-h t-H CM CM OOOO OOOO

00 t* TjH TjH CM COtJH CO OOOO

<* CO 00 O CO

CO to tJt * CO

CM 00 -hh O

CO CM CM CM 00 CO r}H CM o r-ir-ir-lT-i rH 00 CO ^

^° 2 <d 5 « -e

M)03 2 O 03 S S^.S'S^ o

03 bD rt § O +=» llj^lo?

g-cS-sa^

a ^o ^

.a «t-sa'S

B 03 ^ jh 03 ft %f*£i S ^ 03 O^H-"

.9 03 -g s j s

03 n O.S O 03

C3 73

03 03 rQ >» HCj IS rQ rCJ „, 03 73 +» 03 22 > (h bC fn ^3

03 g S 03 C3 tti J

3.1 1 = na as

1
DIMENSIONS OP SPECIAL SCREW THREADS

Table 28.

Pitch diameter tolerances for special screw threads, class 1, loose Jit

9

Threads per inch

Lengths of engage- ment Pitch diameter tolerances for diameters up to and including—

From—

To and

includ- ing— Ms inch Y& inch Yie inch J4 inch % inc a Yz inch % inch

64

56

48

40

36

Indies

I /

I Vi

I %

Inches

1/

%

1/

lA

1/

y

iy

y

iy

y

iy

y

iy

y

iy

3y

iy

Inch

0. 0026

. 0028

. 0052

. 0031

. 0054

. 0034

. 0057

Inch

0. 0026

. 0028

. 0054

. 0031

. 0056

1

. 0034

. 0057

. 0036

. 0057

. 0038

. 0057

Inch

0. 0034

.0034

. 0055

. 0034

. 0057

. 0034

. 0057

. 0036

. 0057

. 0038

. 0057

. 0043

. 0057

. 0046

. 0057

. 0051

. 0057

. 0098

Inch

0. 0038

. 0038

. 0056

. 0038

. 0057

. 0038

. 0057

. 0038

. 0057

. 0038

. 0057

2 . 0043

. 0057

. 0046

. 0057

1

. 0051

. 0057

. 0100

. 0057

. 0057

. 0102

. 0063

. 0063

. 0105

Inch

0. 0042

. 0044

. 0056

. 0046

. 0057

. 0046

. 0057

. 0046

. 0057

. 0046

. 0057

. 0046

. 0057

2

. 0046

. 0057

. 0051

. 0057

. 0102

. 0057

. 0057

. 0104

1

. 0063

. 0063

. 0107

. 0070

. 0070

. 0111

. 0075

. 0079

. 0115

Inch

0. 0044

. 0046

. 0056

. 0048

. 0057

. 0051

. 0057

. 0051

. 0057

. 0051

. 0057

. 0051

. 0057

. 0051

. 0057

2

. 0051

. 0057

. 0102

. 0057

. 0057

. 0106

. 0063

. 0063

. 0109

. 0070

. 0070

. 0113

. 0077

. 0079

. 0117

. 0087

. 0117

. 0167

. 0095

. 0125

. 0175

Inch

0. 0047

. 0049

. 0056

. 0051 .0057

. 0054

. 0057

. 0056

. 0057

. 0057

. 0057

. 0057

. 0057

. 0057

.0057

. 0057

.0057

. 0102

. 0057

. 0057

. 0109

. 0063

2 . 0063

.0112

. 0070

. 0070

. 0116

. 0079

. 0079

. 0120

1

. 0092

. 0120

. 0171

. 0098

. 0128

. 0178

. 0109

. 0139

. 0189

I y

32

28

{ y

24

I y

20 /

I I'A

18 H

I 1/2

16

3y

1/2 3y

iy

3y

iy

3

13

6

136

136

y

I iy

14 ___ H

I 1/2

12 y

10 { i

I 3

8 j 1

I 3

6 | 1

I 3

1 Standard size of the American National coarse-thread series.

2 Standard size of the American National fine-thread series. Note.—It is preferable to avoid the use of tolerances set in italics by choosing a closer fit. shorter length of engagement, coarser pitch, or smaller diameter.
10 NATIONAL SCREW THREAD COMMISSION

Pitch diameter tolerances for special screw threads, class 1, loose fit—Continued

64.

56.

48_

40.

36.

32_

28.

24.

20.

18.

16.

14.

12.

10.

Threads per inch

Lengths of engage- ment

FromInches

Y2 IK

v-A

1H

/2 1/2

To and

includ- ing—

Inches

1/2

1/2%

1/2 1/

1/2X

1/

3%

l/2 3H

1/

3

136

13

6

136

136

Pitch diameter tolerances for diameters up to and including1 inch

Inch

0. 0050

. 0052

. 0056

. 0054

. 0062

. 0057

. 0068

. 0058

. 0070

. 0060

. 0070

. 0063

. 0070

. 0066

. 0070

. 0070

. 0070

. 0102

. 0070

. 0070

. 0112

. 0070

. 0070

. 0115

. 0070

2

. 0070

. 0119

. 0079

. 0079

. 0123

. 0093

. 0123

. 0173

1

. 0111

. 0131

. 0181

. 0112

. 0142

. 0192

. 0130

. 0160

. 0210

inches

Inch

0. 0052

. 0056

. 0056

. 0058

. 0062

. 0061

. 0068

. 0063

. 0072

. 0065

. 0076

. 0067

. 0079

. 0070

. 0079

. 0074

. 0079

. 0102

. 0077

. 0079

. 0114

. 0079

. 0079

. 0120

. 0079

. 0079

. 0123

. 0079

. 0079

. 0127

. 0098

. 0128

.0178

. 0111

. 0135

. 0185

. 0116

1

. 0145

. 0196

. 0134

. 0164

. 0215

2 inches 3 inches 4 inches 6 inches 8 inches

Inch Inch Inch Inch Inch

0. 0062

. 0062

. 0065

. 0068

. 0067

. 0072

. 0069

. 0076

. 0071

. 0086

. 0074

. 0089

0. 0072

. 0072

. 0075

. 0076

. 0077

. 0086

. 0080

. 0092

0. 0083

. 0086

. 0086

. 0092

. 0078 . 0084 . 0090 0. 0099

. 0093 . 0099 . 0102 . 0102

. 0102 . 0102 . 0102 . 0102

. 0080 . 0087 . 0092 . 0101 0. 0109

. 0095 . 0102 . 0107 . 0114 . 0114

. 0114 . 0114 . 0114 . 0114 .0114

. 0083 . 0090 . 0095 . 0104 . 0112

. 0098 . 0105 . 0110 . 0119 . 0126

. 0123 . 0126 . 0126 . 0126 . 0126

. 0087 . 0093 . 0099 . 0108 . 0115

. 0102 . 0108 . 0114 . 0123 . 0130

. 0127 . 0133 . 0139 . 0140 . 0140

. 0091 . 0097 . 0103 . 0112 . 0119

. 0106 . 0112 . 0118 . 0127 . 0134

. 0131 . 0137 . 0143 . 0152 . 0158

. 0102 . 0108 . 0113 . 0122 . 0130

2

. 0132 . 0138 . 0143 . 0152 . 0160

. 0181 . 0184 .0184 . 0184 . 0184

. 0111 . 0115 . 0121 . 0130 . 0137

. 0139 2 . 0145 . 0151 . 0160 . 0167

. 0189 . 0195 . 0201 . 0210 . 0217

. 0120 . 0126 . 0132 . 0141 .0148

. 0150 . 0156 . 0162 . 0171 . 0178

. 0200 . 0206 . 0212 . 0221 . 0228

. 0138 . 0145 . 0150 . 0159 . 0167

. 0168 1

. 0204 . 0204 . 0204 . 0204

. 0218 . 0225 . 0230 . 0239 . 0247

1 Standard size of the American National coarse-thread series.

2 Standard size of the American National fine-thread series. Note.—It is preferable to avoid the use of tolerances set in italics by choosing a closer fit, shorter length of engagement, coarser pitch, or smaller diameter.
DIMENSIONS OF SPECIAL SCREW THREADS

Table 28.Pitch diameter tolerances for special screw threads, class 1, loose jit—Continued

11

Threads per inch

Lengths of engage- ment

From—

To and

includ- ing—

Pitch diameter tolerances for diameters up to and including—

10 inches 12 inches 14 inches 16 inches 18 inches 20 inches

18.

16.

14.

12.

10.

Inches

72 IK

1/2

1/2/2 1/2

Inches%

1/2/

1/2

1/2 3%

3

13

6

136

13

6

13

6

Inch

0. 0114

. 0114

.0114

.0118

. 0126

. 0126

. 0122

. 0137

. 0140

. 0126

. 0141 .0158

. 0136

. 0166

. 0184

.0144

.0174

. 0222

.0155

.0185

.0235

.0173

. 0204

. 0253

Inch

0. 0124

. 0126

. 0126

. 0128

.0140

. 0140

.0132

. 0147

. 0158

. . 0142

. 0172

. 0184

. 0150

. 0180

.0161

.0191

. 0241 .0179

.0209

. 0259

Inch Inch Inch Inch)

0. 0133

. Olio

.0140

. 0138

. 0153

. 0158

. 0148

.0178

. 0184

. 0156

. 0186

. 0166

. 0196

.0246

. 0185

. 0215

. 0265

0. 0138

.0140

.0140

.0143

. 0158

. 0158

.0153

.0183

.0184

.0161

.0191

0. 0148

. 0158

. 0158

. 0158

.0184

.0184

. 0166

. 0196

.0172

. 0202

. 0252

.0190

. 0220

. 0270

. 0176

. 0206

.0256

. 0195

. 0225

. 0275

0. 0152

.0158

.0158

.0163

.0184

.0184

.0170

. 0200

.0181

. 0211 .0261

. 0199

. 0229

. 0279 Note.—It is preferable to avoid the use of tolerances set in italics by choosing a closer fit. shorter length of engagement, coarser pitch, or smaller diameter.
12 NATIONAL SCREW THREAD COMMISSION

Table 29.

Pitch diameter tolerances for special screw threads, class 2, free fit

Threads per inch

Lengths of engage- ment

From- To andinclud- ing—

Pitch diameter tolerances for diameters up to and including

H6 inch H inch 16 inch H inch % inch H inch

64.

56.

48.

40.

36.

32.

28.

24.

20.

18.

16.

14.

12.

10.

Inches

V2 1/2

1H

1/

Inches

1/

Z

1/

N

%

1/2%

1/

H

1/2

/2 1/2

/2 1/

31/

3z

1/2 3

13

6

13

6

13

6

Inch

0. 0019

. 0020

. 0038

. 0022

. 0039

. 0024

. 0041

Inch

0. 0019

. 0020

. 0040

. 0022

. 0041

1

. 0024

. 0041

. 0025

. 0041

. 0027

. 0041

Inch

0. 0024

. 0024

. 0040

. 0024

. 0041

. 0024

. 0041

. 0025

. 0041

. 0027

. 0041

. 0031

. 0041

. 0033

. 0041

. 0036

. 0041

Inch

0. 0027

. 0027

. 004-0

. 0027

. 0041

. 0027

. 0041

. 0027

. 0041

. 0027

. 0041

2

. 0031

. 0041

. 0033

. 0041

1

. 0038

. 0041

. 0039

. 0041

. 0079

. 0040

. 0045

. 0080

Inch

0. 0030

. 0031

. 0040

. 0032

. 0041

. 0033

. 0041

. 0033

. 0041

. 0033

. 0041

. 0033

. 0041

2

. 0033

. 0041

. 0036

. 0041

. 0041

. 0041

. 0081

1

. 0045

. 0045

. 0082

. 0045

. 0049

. 0084

. 0046

. 0056

. 0086

Inch

0. 0032

. 0033

. 0040

. 0034

. 0041

. 0035

. 0041

. 0036

. 0041

. 0036

. 0041

. 0036

. 0041

. 0036

. 0041

2

. 0036

. 0041

. 0041

. 0041

. 0082

. 0045

. 0045

. 0084

. 0048

. 0049

. 0086

. 0048

. 0056

. 0088

. 0056

. 0088

. 0128

. 0060

. 0090

. 0140

1 Standard size of the American National coarse-thread series.

2 Standard size of the American National fine-thread series. Note.—It is preferable to avoid the use of tolerances set in italics by choosing a closer fit, shorter length

of engagement, coarser pitch, or smaller diameter.
DIMENSIONS OF SPECIAL SCKEW THREADS

Table 29.

Pitch diameter tolerances for speical screw threads, class 2, free fit—Continued

13

Threads per inch

Lengths of engage ment

From- To andinclud- ing—

Pitch diameter tolerances for diameters up to and including1 inch 134 inches 2 inches 3 inches 4 inches 6 inches 8 inches

Inch Inch Inch Inch Inch

0. 0048

. 0048

. 0050

. 0050

. 0051

. 0054

. 0052

. 0062

. 0054

. 0066

0. 0054

.0054

. 0058

. 0062

. 0060

. 0066

0. 0062

. 0062

. 0065

. 0066

. 0056 . 0062 .0067 0. 0072

. 0071 . 0072 . 0072 . 0072

. 0057 . 0063 . 0069 . 0078 0. 0082

. 0072 . 0078 . 0082 . 0082 . 0082

. 0082 . 0082 . 0082 . 0082 . 0082

. 0058 . 0065 . 0070 . 0079 . 0087

. 0073 . 0080 . 0085 . 0090 . 0090

. 0090 . 0090 . 0090 . 0090 . 0090

. 0060 . 0066 . 0072 . 0081 . 0088

. 0075 . 0081 . 0087 . 0096 . 0098

. 0098 . 0098 . 0098 . 0098 . 0098

. 0062 . 0068 . 0074 . 0083 . 0090

. 0077 . 0083 . 0089 . 0098 .0105

. 0100 . 0108 . 0112 . 0112 . 0112

. 0070 . 0076 . 0082 . 0091 . 0098

2

. 0100 . 0108 . 0112 . 0121 . 0128

. 0128 . 0128 . 0128 . 0128 . 0128

. 0076 . 0080 . 0085 . 0094 . 0102

. 0104 2

. 0110 . 0115 . 0124 . 0132

. 0152 . 0152 . 0152 .0152 .0152

. 0079 . 0085 . 0091 . 0100 .0107

. 0109 . 0115 . 0121 . 0130 . 0137

. 0159 . 0165 . 0171 . 0180 .0187

. 0088 . 0095 . 0100 . 0109 . 0117

. 0118 K 0140 . 0140 . 0140 . 0147

. 0168 .0175 . 0180 . 0189 . 0197

64.

56.

48.

40.

36.

32.

28.

24.

20.

18.

16.

14.

12.

10.

Inches Inches

i k

72 1/2

1/2

/2

, itf

1/

1/2K

1/

1/2

72 1/2

1/2

1/2

1/2 3

72 IK

72 1/2 3

1/2 3

13

6

136

13

6

136

Inch

0. 0038

Inch

. 0038

. 0040

0. 0040

. 0040

. 0039

. 0044

. 0044

.0044

. 0041

. 0048

. 0045

. 0048

. 0042

. 0049

. 0046

. 0050

. 0043

. 0049

. 0047

. 0054

. 0044

. 0049

. 0048

. 0056

. 0045

. 0049

. 0050

. 0056

. 0047

. 0049

. 0052

. 0056

. 0049

. 0049

. 0082

. 0053

. 0056

. 0082

. 0049

. 0049

. 0090

. 0054

. 0056

. 0090

. 0049

2

. 0049

. 0092

. 0056

. 0056

. 0096

. 0054

. 0056

. 0094

. 0056

2

. 0056

. 0098

. 0064

. 0094

. 0128

. 0066

. 0098

. 0128

K 0076

. 0095

. 0145

. 0076

. 0100

. 0150

. 0071

. 0101

. 0151

. 0075

K 0101 .0155

. 0080

. 0110

. 0160

. 0084

. 0114

. 0164

1 Standard size of the American National coarse-thread series.

2 Standard size of the American National fine-thread series. Note.—It is preferable to avoid the use of tolerances set in italics by choosing a closer fit, shorter length

of engagement, coarser pitch, or smaller diameter.
NATIONAL SCREW THEEAD COMMISSION

Table 29.

Pitch diameter tolerances for special screw threads, class 2, free fit—Continued

16.

14.

12.

10

Threads per inch

Lengths of engage- ment

FromInches

V2 1/2

1/2

To and

includ- ing—

Inches %

1/2

/2 1/2 3ik

3

13

6

13

6

13

6

136

Pitch diameter tolerances for diameters up to and including—

10 inches

Inch

0. 0090

. 0090

. 0090

. 0095

. 0098

. 0098

. 0097

. 0112

. 0112

. 0105

. 0128

. 0128

. 0109

. 0139

. 0152

. 0114

. 0144

. 0194

. 0123

. 0153

. 0203

12 inches

Inch

0. 0098

. 0098

. 0098

. 0103

. 0112

. 0112

. 0111

. 0128

. 0128

. 0115

. 0145

. 0152

. 0120

. 0150

. 0200

. 0129

. 0159

. 0209

14 inches

Inch

0. 0109

. 0112

. 0112

. 0116

. 01 28

. 0128

. 0120

. 0150

. 0152

. 0126

. 0156

. 0202

. 0135

. 0165

. 0215

16 inches

Inch

0. 0112

. 0112

. 0112

. 0122

. 0128

. 0128

. 0125

. 0152

. 0152

. 0131

. 0161

0140

0170

0220

18 inches

Inch

0. 0126

. 0128

. 0128

. 0130

. 0152

. 0152

. 0136

. 0166

0145

0175

0225

20 inches

Inch

0. 0128

. 0135

. 0152

. 0152

. 0140

. 0170

. 0149

. 0199

. 0229

24 inches

Inch

0. 0143

. 0152

.0152

. 0149

. 0179

. 0158

. 0188

. 0238 Note.—It is preferable to avoid the use of tolerances set in italics by choosing a closer fit, shorter length

of engagement, coarser pitch, or smaller diameter.
DIMENSIONS OF SPECIAL SCREW THREADS

Table 30.

Pitch diameter tolerances for special screw threads, class 8, medium fit

15

Threads per inch

64

56

48

40

36

32

28

24

20

18

16

14.

12.

10.

8_.

6_.

Lengths of engage- ment

FromInches

Y2

l

1 ^

l/2 /

To and

includ- ing—

Inches1/2/

/

1/2

72

72 V/2

1/

Y2 1/2 3/

1/2 3

/2 1/2 3

1/2 3

13

6

13

6'

136

Pitch diameter tolerances for diameters up to and includingHe inch

Inch

0. 0014

. 0030

. 0015

. 0030

. 0016

. 0030

. 0017

. 0030

H inch

Inch

0. 0014

. 0030

. 0015

. 0030

. 0016

. 0030

». 0017

. 0030

. 0018

. 0030

. 0019

. 0030

3A& inch

Inch

0. 0017

.0030

. 0017

. 0030

. 0017

. 0030

. 0017

. 0030

. 0018

. 0030

. 0019

. 0030

. 0022

. 0030

. 0024

. 0030

. 0025

. 0030

. 0065

inch

Inch

0. 0019

. 0030

. 0019

. 0030

. 0019

. 0030

. 0019

. 0030

. 0019

. 0030

. 0019

. 0030

2. 0022

. 0030

. 0024

. 0030

K 0026

. 0030

. 0066

. 0027

. 0030

. 0067

. 0028

. 0032

. 0068

% inch

Inch

0. 0023

. 0030

. 0024

. 0030

. 0024

. 0030

. 0024

. 0030

. 0024

. 0030

. 0024

. 0030

. 0024

. 0030

2

. 0024

. 0030

. 0026

. 0030

. 0068

. 0030

. 0030

. 0069

K 0032

. 0032

. 0070

. 0032

. 0036

. 0071

. 0032

. 0040

. 0071

Yi inch

Inch

0. 0025

. 0030

. 0026

. 0030

. 0026

. 0030

. 0026

. 0030

. 0026

. 0030

. 0026

. 0030

. 0026

. 0030

. 0026

. 0030

2 0026

. 0030

. 0070

. 0030

. 0030

. 0071

. 0032

. 0032

. 0071

. 0036

. 0036

. 0071

. 0036

. 0040

. 0071

. 0040

. 0071

. 0120

. 0042

. 0071

. 0122

1 Standard size of the American National coarse-thread series.

a Standard size of the American National fine-thread series.
16 NATIONAL SCREW THREAD COMMISSION

Table 30.

Pitch diameter tolerances for special screw threads, class 8, medium fit—

Continued

Threads per inch

64 I

56 I " 1

40 I

36 I

32 I

28 1

24 I

20 I

18 I

16 I

14

12 I

10 I

8_ I

6____

4

Lengths of engage- ment

FromInches /

ft 1/

/

1/2

To and

includ- ing—

Inches

72 1/2

1/2

1/2

%

1/

1/2

1/2

/2 1/

3

1/2 3

3

1/2 3

13

6

13

6

13

6

136

Pitch diameter tolerances for diameters up to and including—

1 inch

Inch

0. 0031

. 0036

. 0032

. 0036

. 0032

. 0036

. 0033

. 0036

. 0033

. 0036

. 0034

. 0036

. 0034

. 0036

. 0035

. 0036

. 0036

. 0036

. 0071

. 0036

. 0036

. 0071

. 0036

. 0036

. 0071

. 0036

2. 0036

. 0071

. 0040

. 0040

. 0071

. 0046

. 0071

. 0126

K 0054

. 0071

. 0128

. 0054

. 0071

. 0130

. 0055

. 0085

. 0135

1H inches

Inch

0. 0036

. Q038

. 0036

. 0040

. 0037

. 0040

. 0037

. 0040

. 0038

. 0040

. 0038

. 0040

. 0039

. 0040

. 0040

. 0040

. 0040

. 0040

. 0071

. 0040

. 0040

. 0071

. 0040

. 0040

. 0071

. 0040

. 0040

. 0071

. 0040

2

. 0040

. 0071

. 0050

. 0071

. 0128

. 0054

. 0071

. 0132

. 0055

1. 0071

. 0135

. 0059

. 0089

. 0139

2 inches

Inch

0. 0038

. 0038

. 0040

. 0040

. 0041

. 0044

. 0041

. 0048

. 0042

. 0050

. 0042

. 0054

. 0043

. 0058

. 0044

. 0059

. 0045

. 0060

. 0072

. 0045

. 0060

. 0082

. 0046

. 0061

. 0084

. 0047

. 0062

. 0084

. 0048

. 0063

. 0084

. 0054

2. 0084

. 0128

. 0056

. 0086

. 0136

. 0059

. 0089

. 0139

. 0063

. 0093

. 0143

inches

Inch

0. 0044

. 00U

. 0048

. 0048

. 0048

. 0050

. 0048

. 0054

. 0049

. 0062

. 0050

. 0065

. 0051

. 0066

. 0072

. 0051

. 0066

. 0052

. 0067

. 0090

. 0053

. 0068

. 0092

. 0054

. 0069

. 0092

. 0060

. 0092

. 0128

. 0062

2 0092

. 0142

. 0065

. 0095

. 0145

. 0070

K 0097

. 0150

4 inches

Inch

0. 0050

. 0050

. 0054

.0054

. 0054

. 0062

. 0055

. 0066

. 0056

. 0071

. 0072

. 0057

. 0072

. 0082

. 0058

. 0073

. 0090

. 0058

. 0073

. 0098

. 0059

. 0074

. 0099

. 0066

. 0099

. 0128

. 0068

. 0099

. 0148

. 0070

. 0100

. 0150

.0075

. 0105

. 0155

inches

Inch

0. 0062

. 0062

. 0064

. 0066

. 0065

. 0072

. 0072

. 0066

. 0081

. 0082

. 0066

. 0081

. 0090

. 0067

. 0082

. 0098

. 0068

. 0083

. 0108

. 0075

. 0108

. 0128

. 0077

. 0108

. 0152

. 0079

. 0109

. 0159

. 0084

. 0114

. 0164

8 inches

Inch

0. 0072

. 0072

. 0072

. 0073

. 0082

. 0082

. 0074

. 0089

. 0090

. 0075

. 0090

. 0098'

. 0076

. 0091

. 0112

. 0082

. 0112

. 0128

. 0084

. 0114

. 0152

. 0087

.0117

. 0167

. 0092

. 0122

. 0172

1 Standard size of the American National coarse-thread series.

2 Standard size of the American National fine-thread series. Note.—It is preferable to avoid the use of tolerances set in italics by choosing a closer fit, shorter length

of engagement, coarser pitch, or smaller diameter.
DIMENSIONS OF SPECIAL SCREW THREADS

Table 30.

Pitch diameter tolerances for special screw threads, class 8, medium fit—Continued

17

Threads per inch

Lengths of engage- ment

From- To andinclud- ing—

Pitch diameter tolerances for diameters up to and including—

10 inches 12 inches 14 inches 16 inches 18 inches 20 inches 24 inches

18.

16.

14.

12.

10.

InchesIK

l/2

1/2/

1/2

Inches1/2

/2 1/2 3/

1/2 3

1/2 3

13

6

136

136

136

Inch

0. 0080

Inch

. 0082

. 0081

. 0090

. 0090

. 0082

. 0097

. 0098

. 0083

. 0098

. 0112

. 0089

. 0119

. 0128

. 0091

. 0121

. 0152

. 0094

. 0124

. 0174

. 0098

. 0128

. 0178

0. 0087

. 0090

. 0090

. 0088

. 0098

. 0098

. 0089

. 0104

. 0112

. 0095

. 0125

. 0128

. 0097

. 0127

. 0152

. 0100

. 0130

. 0180

. 0104

. 0134

. 0184

Inch Inch Inch Inch Inch

0. 0093

. 0098

. 0098

. 0094

. 0109

. 0112

. 0101

. 0128

. 0128

. 0102

. 0132

. 0152

. 0105

. 0135

. 0185

. 0110

. 0140

. 0190

0. 0098

. 0098

. 0098

. 0099

. 0112

. 0112

. 0106

. 0128

0. 0104

. 0112

. 0112

. 0111

0108

. 0138

. 0152

. 0110

. 0140

. 0190

. 0115

. 0145

. 0195

0128

0113

0143 0152

0115

0145

0195

0120

0150

0200

0. 0109

. 0112

. 0112

. 0115

. 0128

. 0128

. 0117

. 0147

. 0152

. 0120

. 0150

. 0200

. 0124

. 0154

. 0204

0. 0124

. 0128

. 0128

. 0126

. 0152

.0152

. 0128

. 0158

. 0202

.0133

. 0163

. 0213 Note.—It is preferable to avoid the use of tolerances set in italics by choosing a closer fit, shorter length

of engagement, coarser pitch, or smaller diameter.
18 NATIONAL SCEEW THREAD COMMISSION

Table 31.

Pitch diameter tolerances for special screw threads, class 4, close Jit

Threads per inch

64.

56.

4S.

40.

36.

32.

28.

24.

20.

18.

16.

14.

12.

10.

Lengths of engage- ment

FromInches

iy2

To and

includ- ing—

Inchesiy2

1/2 3

1^2 3

Pitch diameter tolerances for diameters up to and including

Yi6 inch

Inch

0. 0007

. 0015

. 0028

. 0007

. 0015

. 0028

. 0008

. 0015

. 0029

. 0009

. 0015

. 0029

\i inch

Inch

0. 0007

. 0015

. 0029

. 0007

.0015

. 0029

. 0008

. 0015

. 0030

1 . 0009

. 0015

. 0030

. 0009

. 0015

. 0030

. 0010

. 0015

. 0030

He inch

Inch

0. 0009

. 0015

. 0030

. 0009

. 0015

. 0030

. 0009

. 0015

. 0030

. 0009

. 0015

. 0031

. 0009

. 0015

. 00.31

. 0010

. 0015

. 0031

. 0011

. 0015

. 0032

. 0012

. 0015

. 0032

. 0012

. 0015

. 0032

]4 inch

Inch

0. 0010

. 0015

. 0031

. 0010

. 0015

. 0031

. 0010

. 0015

. 0031

. 0010

. 0015

. 0032

. 0010

. 0015

. 0032

. 0010

. 0015

. 0032

2

. 0011

. 0015

. 0032

. 0012

. 0015

. 0033

K 0013

. 0015

. 0033

. 0013

. 0015

. 0033

. 0014

. 0016

. 0034

% inch

Inch

0. 0012

0. 0015

. 0032

. 0012

. 0015

. 0032

. 0012

. 0015

. 0032

. 0012

. 0015

. 0033

. 0012

. 0015

. 0033

. 0012

. 0015

. 0033

. 0012

. 0015

. 0033

2

. 0012

. 0015

. 0034

. 0013

. 0015

. 0034

. 0015

. 0015

. 0034

1. 0016

. 0016

. 0035

. 0016

. 0018

. 0035

. 0016

. 0020

. 0036

H inch

Inch

0. 0013

. 0015

. 0033

. 0013

. 0015

. 0033

. 0013

. 0015

. 0033

. 0013

. 0015

. 0034

. 0013

. 0015

. 0034

. 0013

. 0015

. 0034

. 0013

. 0015

. 0034

. 0013

. 0015

. 0035

2. 0013

. 0015

. 0035

. 0015

. 0015

. 0035

. 0016

. 0016

. 0036

. 0018

. 0018

. 0036

. 0018

. 0020

. 0036

. 0020

. 0036

. 0060

. 0021

. 0036

. 0061

1 Standard size of the American National coarse-thread series.

2 Standard size of the American National fine-thread series.
Table 31

DIMENSIONS OF SPECIAL SCREW THREADS

.

Pitch diameter tolerances for special screw threads, class 4, close fit—

1

•Continued

19

Pitch diameter tolerances for diameters up to and including— Threads per inch From—

To and

includ- 1 inch \Yi inches 2 inches 3 inches 4 inches 6 inches 8 inches

Inches Inches Inch Inch Inch Inch Inch Inch Inch

Y2 0. 0016 0. 0018 0. 0020 0. 0023 0. 0026 0. 0030 0. 0034

64 IY2 . 0018 . 0020 . 0027 . 0030 . 0033 . 0038 . 0038

11/ 3 . 0036 . 0036 . 0Q88 . 0038 . 0038 . 0088 . 0038

. 0016 . 0018 . 0020 . 0023 . 0026 . 0030 . 0034

56 1/2 1/2 . 0018 . 0020 . 0027 . 0031 . 0033 . 0038 . 0040

i 1/2 3

aao/2

. UUoo AAO/3

. UUoo . 0040 . 0040 . 0040 . 0040 . 0040

. 0016 . 0018 . 0020 . 0023 . 0026 . 0031 . 0034

48 I/2 . 0018 . 0020 . 0028 . 0031 . 0034 . 0038 . 0042

[ 1% 3 . 0036 . 0036 . 0040 . 0043 . 0044 . 0044 . 0044

Y2 . 0016 . 0018 . 0021 . 0024 . 0027 . 0031 . 0035

40 IY2 . 0018 . 0020 . 0028 . 0031 . 0034 . 0038 . 0042

11/

l VA . UU06 AAO C!

. UUoo . 0041 . 0044 . 0047 AA A O. UU45 . 0048

Y2 . 0017 . 0019 . 0021 . 0024 . 0027 . 0031 .0035

36 % IY2 . 0018 . 0020 . 0028 . 0031 . 0034 . 0039 . 0042

11/

I 1/2 3

aao/2

. UUoo . 0036 . 0041 . 0044 . 0047 AA r A. 0U5U . 0050

. 0017 . 0019 . 0021 . 0024 . 0027 . 0031 . 0035

32 I/2 . 0018 . 0020 . 0029 . 0032 . 0034 . 0039 . 0043

11/

1 1% . UUoo AAO/2

. UUoo . 0041 AA A A

. UU44 AA A n

. UU47 AA C 1. UU51 aa er a. UU54

. 0017 . 0019 . 0021 . 0024 . 0027 . 0032 .0036

28 IK . 0018 . 0020 . 0029 . 0032 . 0035 . 0039 . 0043

1 1/

I 1/2 QO aaoc . UUoo AAQA . UUoo AA A 1

. UU41 AA A A

. UU44 AA A 1. UU47 . UU52 AACC

. UUoO

. 0018 . 0020 . 0022 . 0025 . 0028 . 0032 . 0036 24 Vi 1/4 . 0018 . 0020 . 0029 . 0032 . 0035 . 0040 . 0043

11/

I 1/4 AAOC

. UUOO AAO/3

. UUoo . 0042 AA A e. UU45 AA A O. UU48 AACO. 0052 . UUoo

Y2 . 0018 . 0020 . 0022 . 0025 . 0028 . 0033 . 0036

20 1/2 . 0018 . 0020 . 0030 . 0033 . 0036 . 0040 . 0044

l 1/4 3 . 0036 . 0036 . 0042 . 0045 . 0048 . 0053 . 0056

H . 0018 . 0020 . 0023 . 0026 . 0028 . 0033 . 0037

18 1/2 . 0018 . 0020 . 0030 . 0033 >

. 0036 . 0040 . 0044

11/

I 1/4 3 . 0036 . UUoo . 0042 . 0046 *

. 0048 AACO

. UUoo AA CT. 0U57

Y2 . 0018 . 0020 . 0023 .0026 . 0029 . 0033 . 0037

16 1/2 . 0018 . 0020 . 0030 . 0033 . 0036 . 0041 . 0044

1 1/

I 1/4 AA O O

. UUoo . UUoo AA A O. 0042 AA A a. UU40 AA A A

. uu4y AA CO

. UUoo . UUo7 H . 0018 . 0020 . 0023 . 0026 . 0029 . 0034 . 0038

14 H IK 2

. 0018 . 0020 . 0031 . 0034 . 0037 . 0041 . 0045

I 1>4 3 . 0036 AAO/2

. UUoo . 0042 . 0046 AA A A. 0049 AA C A

. UU54 . UU58

. 0020 . 0020 . 0024 . 0027 . 0030 . 0034 . 0038

12 Y2 1/4 . 0020 2

. 0020 . 0031 . 0034 . 0037 . 0042 . 0046

1 1/ AAO/2

. UUOO AAO/2. UUoo AA A O. 0042 AA A a

. UU4o AA CA

. UUoU AA C A 0U54 AACO . UU58

1 A

l . 0023 . 0023 . 0027 . 0030 . 0033 . 0037 . 0041

| 1 3 . 0036 . 0036 2. 0042 . 0046 . 0050 . 0054 . 0058

l 3 6 . 0063 . 0065 . 0067 . 0070 . 0073 . 0077 . 0081

8

1 *. 0027 . 0027 . 0028 . 0031 . 0034 . 0038 . 0042

J 1 QO . 003fi uuou • 003fi UVJOU 004-3 2 004fi 00 ^0 . 00^4. \jyjort . UUOO

I 3 6 . 0084 . 0066 . 0068 . 0071 . 0074 . 0078 . 0082

6

1 . 0027 . 0027 . 0029 . 0032 . 0035 . 0040 . 0043

1 3 . 0036 K 0036 . 0044 . 0047 . 0050 . 0055 . 0058

I 3 6 . 0065 .0067 . 0069 . 0072 . 0075 . 0080 . 0083

1 . 0028 . 0030 . 0032 . 0035 . 0038 . 0042 . 0046

4 | 1 3 . 0043 . 0045 . 0047 1. 0048 . 0053 . 0057 . 0061

I 3 6 . 0068 . 0070 . 0072 .0075 . 0078 . 0082 . 0086

1 Standard size of the American National coarse-thread series.

2 Standard size of the American National fine-thread series. Note.—It is preferable to avoid the use of tolerances set in italics by choosing a shorter length of engage- ment, coarser pitch, or smaller diameter.

I
20 NATIONAL SCREW THREAD COMMISSION

Table 31.

Pitch diameter tolerances for special screw threads, class 4, close fit—Continued

Threads per in

Lengths of engage- ment

From

To and

includ- ing—

Pitch diameter tolerances for diameters up to and including—

10 inches 12 inches 14 inches 16 inches 18 inches 20 inches 24 inches

64.

56.

48.

40.

36.

32.

28.

24.

20.

18.

16.

14.

12.

10.

Inches /

1/2

Y2 i/2

V2 1/2

V2 1/2

V2 iy2

1/2

/2

VA

h

/

VA

Inches Inch

0. 0037

. 0038

. 0088

y2 . 0037

iy2 . oo%o

3 . 0040

1/2 3

1/2/

1/2 3

-72

1/2 3

/2 1/2 3 /

1/2 3%

1/2 3

136

136

13

6

13

6

Inch Inch Inch Inch Inch Inch

. 0038

. 0044

. 0044

. 0038

. 0046

. 0048

. 0038

. 0046

. 0050

. 0038

. 0046

. 0054

. 0039

. 0046

. 0059

. 0039

. 0047

. 0059

. 0040

. 0047

. 0060

. 0040

. 0047

. 0060

. 0040

. 0048

. 0060

. 0041

. 0048

. 0061

. 0041

. 0049

. 0061

. 0044

. 0061

. 0084

. 0045

. 0061

. 0085

. 0047

. 0062

. 0087

. 0049

. 0064

. 0089

0. 0040

. 0040

. 0040

. 0041

. 0044

. 0044

. 0041

. 0048

. 0048

. 0041

. 0049

. 0050

. 0041

. 0049

. 0054

. 0042

. 0049

. 0062

. 0042

. 0050

. 0062

. 0043

. 0050

. 0063

. 0043

. 0050

. 0063

. 0043

. 0051

. 0063

. 0044

. 0051

. 0064

. 0044

. 0052

. 0064

. 0048

. 0064

. 0088

. 0048

. 0064

. 0088

. 0050

. 0065

. 0090

. 0052

. 0067

. 0092

0. 0044

. 0044

. 0044

. 0044

. 0048

. 0048

. 0044

. 0050

. 0050

. 0044

. 0052

. 0054

. 0045

. 0052

. 0062

. 0045

. 0052

. 0065

. 0046

. 0053

. 0066

. 0046

. 0053

. 0066

. 0046

. 0054

. 0066

. 0047

. 0054

. 0067

. 0047

. 0055

. 0067

. 0050

. 0067

. 0090

. 0051

. 0067

. 0091

. 0053

. 0068

. 0093

. 0055

. 0070

. 0095

0. 0046

. 0048

. 0048

. 0047

. 0050

. 0050

. 0047

. 0054

. 0054

. 0047

. 0055

. 0062

. 0048

. 0055

. 0066

. 0048

. 0056

. 0068

. 0048

. 0056

. 0068

. 0049

. 0056

. 0069

. 0049

. 0057

. 0069

. 0050

. 0057

. 0070

. 0053

. 0070

. 0093

. 0054

. 0070

. 0094

. 0055

. 0070

. 0095

. 0058

. 0073

. 0098

0. 0049

. 0050

. 0050

. 0049

. 0054

. 0054

. 0050

. 0057

. 0062

. 0050

. 0057

. 0066

. 0050

. 0058

. 0070

. 0051

. 0058

. 0071

. 0051

. 0059

. 0071

. 0052

. 0059

. 0072

. 0052

. 0060

. 0072

. 0055

. 0072

. 0095

. 0056

. 0072

. 0096

. 0058

. 0073

. 0098

. 0060

. 0075

. 0100

0. 0052

. 0054

. 0054

. 0052

. 0059

. 0062

. 0052

. 0060

. 0066

. 0053

. 0060

. 0072

. 0053

. 0061

. 0073

. 0053

. 0061

. 0073

. 0054

. 0061

. 0074

. 0054

. 0062

. 0074

. 0058

. 0074

. 0098

. 0059

. 0074

. 0099

. 0060

. 0075

. 0100

. 0062

. 0077

. 0102

0. 0056

. 0062

. 0062

.0057

.0064

. 0066

. 0057

. 0065

.0072

. 0057

. 0065

. 0077

. 0058

. 0065

. 0078

. 0058

. 0066

. 0078

. 0059

. 0066

.0079

. 0062

. 0079

. 0102

. 0063

.0079

. 0103

. 0064

. 0079

.0104

. 0066

. 0082

. 0106

of tolerances set in italics by choosing a shorter length of engage- o



-
4