UNITED STATES DEPARTMENT OF COMMERCE

BUREAU OF STANDARDS

AMERICAN NATIONAL

SCREW THREAD TABLES

FOR SHOP USE

L Standard Threads

(Coarse and Fine Thread Series)

MISCELLANEOUS PUBLICATION OF THE BUREAU OF STANDARDS, No. 98

UNITED STATES DEPARTMENT OF COMMERCE

R. P. LAMONT, Secretary

BUREAU OF STANDARDS

GEORGE K. BURGESS, Director

MISCELLANEOUS PUBLICATION OF THE BUREAU OF STANDARDS, No. 98 AMERICAN NATIONAL

SCREW THREAD TABLES

FOR SHOP USE

I. Standard Threads

(Coarse and Fine Thread Series)

[Recommended Commercial Standard]

SEPTEMBER 23, 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

I. STANDARD THREADS (COARSE AND FINE THREAD SERIES)

ABSTRACT

This publication makes available for convenient use six of the most essential tables of dimensions of fastening screws as published in the 1928 Report of the National Screw Thread Commission (Sec. Ill and Appendix 4), Bureau of Standards Miscellaneous Publication No. 89.1 These tables cover the basic sizes, limiting

dimensions, tolerances, and tap-drill sizes for the American National coarse and fine thread series.

CONTENTS

I. American National coarse-thread series Table 1. American National coarse-thread series Table 15. Limiting dimensions and tolerances, classes 1, 2, 3, and 4 fits, American National

coarse-thread series

II. American National fine-thread series Table 2. American National fine-thread series Table 16. Limiting dimensions and tolerances, classes 1, 2, 3, and 4 fits, American National

fine-thread series

III. Appendix—tap drill sizes Table 107. Sizes c«f tap drills, American National coarse-thread series Table 108. Sizes of tap drills, American National fine-thread series

Figure 3.

American National form of thread

Note: No allowance is shown. This condition exists in class 2, free fit, and class 3, medium fit, where both the minimum nut and the maxi- mum screw are basic. NOTATION n=number of threads per inch

£T=0.866025 p, depth of 60° sharp V thread

A=0.649519 p, depth of American National form of thread

$6ft=0.541266 p, maximum depth of engagement

.F=0.125000 p, width of flat at crest and root of American National form

/=0.108253 p = }&H depth of truncation =46 A J

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.
NATIONAL SCREW THREAD COMMISSION

Si

I CI

lis

Heavy L/r^a. Shows

Figure 7.

Illustration of tolerances and crest clearances for class 2, free fit
DIMENSIONS OF STANDARD SCREW THREADS 3

I. AMERICAN NATIONAL COARSE-THREAD SERIES

The American National coarse-thread series is recommended for general use in engineering

work, in machine construction where conditions are favorable to the use of bolts, screws, and

other threaded components where quick and easy assembly of the parts is desired, and for all work where conditions do not require the use of fine-pitch threads.

Table 1.

American National coarse-thread series

Identification Basic diameters Thread data

Threads

per inch

71 Major

diameter D

Pitch diameter E

Minor, diameter K

Metric

equivalent

of major

diameter

Pitch V

Depth of thread

h

Basic width of

flat

Minimum

width of

flat at major di- ameter of nut

p/24

Helix angle

at basic pitch di- ameter

s

64

5648

40

40

32

3224

24

20

1816

14

1312

1110

98

77

6

54/2

Inches

0. 073

. 086

. 099

. 112

. 125

. 138

. 164

. 190

. 216

. 2500

. 3125

. 3750

. 4375

. 5000

. 5625

. 6250

. 7500

. 8750

1. 0000

1. 1250

1. 2500

1. 5000

1. 7500

2. 0000

2. 2500

2. 5000

2. 7500

3. 0000

3. 0000

Inches

0. 0629

. 0744

. 0855

. 0958

. 1088

. 1177

. 1437

. 1629

. 1889

. 2175

. 2764

. 3344

. 3911

. 4500

. 5084

. 5660

. 6850

. 8028

. 9188

1. 0322

1. 1572

1. 3917

1. 6201

1. 8557

2. 1057

2. 3376

2. 5876

2. 8376

2. 8144

Inches

0. 0527

. 0628

. 0719

. 0795

. 0925

. 0974

. 1234

. 1359

. 1619

. 1850

. 2403

. 2938

. 3447

. 4001

. 4542

. 5069

. 6201

. 7307

. 8376

. 9394

1. 0644

1. 2835

1. 4902

1. 7113

1. 9613

2. 1752

2. 4252

2. 6752

2. 6288

mm

1. 854

2. 184

2. 515

2. 845

3. 175

3. 505

4. 166

4. 826

5. 486

6. 350

7. 938

9. 525

11. 113

12. 700

14. 288

15. 875

19. 050

22. 225

25. 400

28. 575

31. 750

38. 100

44. 450

50. 800

57. 150

63. 500

69. 850

76. 200

76. 200

Inch

0. 01562

. 01786

. 02083

. 02500

. 02500

. 03125

. 03125

. 04167

. 04167

. 05000

. 05556

. 06250

. 07143

. 07692

. 08333

. 09091

. 10000

. 11111

. 12500

. 14286

. 14286

. 16667

. 20000

. 22222

. 22222

. 25000

. 25000

. 25000

. 28571

Inch

0. 01015

. 01160

. 01353

. 01624

. 01624

. 02030

. 02030

. 02706

. 02706

. 03248

. 03608

. 04059

. 04639

. 04996

. 05413

. 05905

. 06495

. 07217

. 08119

. 09279

. 09279

. 10825

. 12990

. 14434

. 14434

. 16238

. 16238

. 16238

. 18558

Inch

0. 00195

. 00223

. 00260

. 00312

. 00312

. 00391

. 00391

. 00521

. 00521

. 00625

. 00694

. 00781

. 00893

. 00962

. 01042

. 01136

. 01250

. 01389

. 01562

. 01786

. 01786

. 02083

. 02500

. 02778

. 02778

. 03125

. 03125

. 03125

. 03571

Inch

0. 00065

. 00074

. 00087

. 00104

. 00104

. 00130

. 00130

. 00174

. 00174

. 00208

. 00231

. 00260

. 00298

. 00321

. 00347

. 00379

. 00417

. 00463

. 00521

. 00595

. 00595

. 00694

. 00833

. 00926

. 00926

. 01042

. 01042

. 01042

. 01190

3122

26

45

1150

58

39

1 1140

24

20

7595640

3129

31

15

1115

11

1 55

1 57

1 46

1 36

1 51

1 Optional. Standard for marine work.
4 NATIONAL SCREW THREAD COMMISSION

Table 15.

Limiting dimensions and tolerances, classes 1, 2, 3, and 4 fits, American National coarse-thread series

Machine screw number

1 2 3 4 5 6 8

Threads per inch

64 56 48 40 40 32

BOLTS AND SCREWS

!Max._

Min_ _ Tol—

!Max__

Min_ _ Tol_—

Class 2, major diameter (threaded [Max. _ parts of unfinished, hot-rolled \ Min_ _ material) I I Tol

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

Min_ _ Tol_„

!Max._

Min__

Tol...

Class 3, medium fit, [Max.

pitch diameter. { Min.

lTol_.

[Max..

Class 4, close fit, pitch diameter { Min__

[Tol__.

NUTS AND TAPPED HOLES

Classes 1, 2, 3, and 4, major diameter. Min.2 . [Max..

Classes 1, 2, 3, and 4, minor diameter _< Min_

lTol_.

Classes 1, 2, 3, and 4, pitch diameter _ Min __ Class 1, loose fit, pitch diameter {toT*

--

Class 2, free fit, pitch diameter {toT*"

Class 3, medium fit, pitch diameter_{^x -

Class 4, close fit, pitch diameter {toT*"

Inch

0. 0723

.0671

.0052

.0730

. 0692

. 0038

.0730

. 0678

. 0052

.0531

.0538

.0622

.0596

.0026

.0629

. 0610

.0019

.0629

. 0615

. 0014

. 0630

. 0623

. 0007

.0730

. 0604

. 0561

. 0043

. 0629

. 0655

. 0026

. 0648

. 0019

. 0643

. 0014

. 0636

. 0007

Inch

0. 0852

. 0796

. 0056

. 0860

. 0820

. 0040

. 0860

. 0804

. 0056

. 0633

.0641

.0736

. 0708

. 0028

. 0744

. 0724

. 0020

. 0744

. 0729

. 0015

. 0746

. 0739

. 0007

. 0860

. 0715

. 0667

. 0048

.0744

. 0772

. 0028

. 0764

. 0020

. 0759

. 0015

. 0751

. 0007

Inch

0. 0981

. 0919

.0062

. 0990

. 0946

. 0044

. 0990

. 0928

. 0062

.0725

.0734

. 0846

. 0815

. 0031

. 0855

. 0833

. 0022

. 0855

. 0839

. 0016

. 0857

. 0849

. 0008

.0990

. 0820

. 0764

. 0056

. 0855

. 0886

. 0031

. 0877

. 0022

. 0871

. 0016

. 0863

. 0008

Inch

0. 1110

. 1042

. 0068

. 11-20

. 1072

. 0048

. 1120

. 1052

. 0068

. 0803

.0813

. 0948

. 0914

. 0034

. 0958

. 0934

. 0024

. 0958

. 0941

. 0017

. 0960

. 0951 .0009

. 1120

. 0913

. 0849

. 0064

. 0958

. 0992

. 0034

. 0982

. 0024

. 0975

. 0017

. 0967

. 0009

Inch

0. 1240

. 1172 .0068

. 1250

. 1202

. 0048

. 1250

. 1182

. 0068

.0933

.0943

. 1078

. 1044 .0034

. 1088

. 1064

. 0024

. 1088

. 1071

. 0017

. 1090

. 1081

. 0009

1250

1043 0979

0064

1088

1122 0034

1112 0024

1105 0017

1097 0009

Inch

0. 1369

. 1293 .0076

. 1380

. 1326

. 0054

. 1380

. 1304

. 0076

. 0986

. 0997

. 1166

. 1128

. 0038

. 1177

. 1150

. 0027

. 1177

. 1158

. 0019

. 1179

. 1169

. 0010

1380 1118

1042 0076

1177

1215 0038

1204 0027

1196 0019

1187 0010

1 See footnote 1 on page 12. 2 See footnote 2 on page 12.
DIMENSIONS OF STANDAKD SCREW THREADS 5

Table 15.

Limiting dimensions and tolerances, classes 1, 2, 3, and 4 fits, American National coarse-thread series—

Continued

Machine screw number or nominal size

10 12 H Me H H

Threads per inch

24 24 20 18 16 14 13

1 9 10 11 12 13 14 15 BOLTS AND SCREWS

[Max..

Class 1, major diameter \ Min__

lTol___

Inch

0. 1887

. 1795

. 0092

Inch

0. 2147

. 2055

. 0092

Inch

0. 2485

. 2383

. 0102

Inch

0. 3109

. 2995

. 0114

Inch

0. 3732

. 3606

. 0126

Inch

0. 4354

. 4214

. 0140

Inch

0. 4978

. 4830

. 0148

[Max..

Classes 2, 3, and 4, major diameter.J Min__

[Tol___

. 1900

. 1834

. 0066

. 2160

. 2094

. 0066

. 2500

. 2428

. 0072

. 3125

. 3043

. 0082

. 3750

. 3660

. 0090

. 4375

. 4277

. 0098

. 5000

. 4896

. 0104

Class 2, major diameter (threaded [Max..

parts of unfinished, hot-rolled I Min_ _ material)- . [Tol

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

. 1900

. 1808

. 0092

. 1376

. 1389

. 2160

. 2068

. 0092

. 1636

. 1649

. 2500

. 2398

. 0102

. 1872

. 1887

. 3125

. 3011

. 0114

. 2427

. 2443

.3750

. 3624

. 0126

. 2965

. 2983

. 4375

. 4235

. 0140

. 3478

. 3499

. 5000

. 4852

. 0148

. 4034

. 4056

[Max..

Class 1, loose fit, pitch diameter { Min,.-

[To1___

. 1616

. 1570

. 0046

. 1876

. 1830

. 0046

. 2160

. 2109

. 0051

. 2748

. 2691

. 0057

. 3326

. 3263

. 0063

. 3890

. 3820

. 0070

. 4478

. 4404

. 0074

[Max..

Class 2, free fit, pitch diameter. _ { Min__

[Tol___

. 1629

.'1596

. 0033

. 1889

. 1856

. 0033

. 2175

. 2139

. 0036

. 2764

. 2723

. 0041

. 3344

. 3299

. 0045

. 3911

. 3862

. 0049

. 4500

. 4448

* . 0052

f Max. _ Class 3, medium fit, pitch diameter. \ Min_ _ [Tol

. 1629

. 1605

. 0024

. 1889

. 1865

. 0024

. 2175

. J149

. 0026

. 2764

. 2734

. 0030

. 3344

. 661Z

. 0032

. 3911

. o87o

. 0036

. 4500

. 4463

. 0037

[Max..

Class 4, close fit, pitch diameter \ Min__

[Xol

NUTS AND TAPPED HOLES

. 1632

. 1620

. 0012

. 1892

. 1880

. 0012

. 2178

. 2165

. 0013

. 2767

. 2752

. 0015

. 3348

. 3332

. 0016

. 3915

. 3897

. 0018

. 4504

. 4485

. 0019

Classes 1, 2, 3, and 4, major diameter. Min.2 _ oi fin . ol^O 4-^7*; . "±0 4 o [Max..

Classes 1, 2, 3, and 4, minor diameter _{ Min. _ lTol___

. 1541

. 1449

. 0092

. 1801

. 1709

. 0092

. 2060

. 1959

. 0101

. 2630

. 2524

. 0106

. 3184

. 3073

. 0111

. 3721

. 3602

. 0119

. 4290

. 4167

. 0123

Classes 1, 2, 3, and 4, pitch diameter. Min _ _ . 1629 . 1889 . 2175 . 2764 .3344 . 3911 . 4500

Class 1, loose fit, pitch diameter {tqI*

- . 1675

. 0046

. 1935

. 0046

. 2226

. 0051

. 2821

. 0057

. 3407

. 0063

. 3981

. 0070

. 4574

. 0074

Class 2, free fit, pitch diameter |J^X-- . 1662

. 0033

. 1922

. 0033

. 2211

. 0036

. 2805

. 0041

. 3389

. 0045

. 3960

. 0049

. 4552

.0052

Class 3, medium fit, pitch diameter. _|^^

x_ -

. 1653

. 0024

. 1913

. 0024

. 2201

. 0026

. 2794

. 0030

. 3376

. 0032

. 3947

. 0036

.4537

.0037

Class 4, close fit, pitch diameter {tcJ

X~~ . 1641

. 0012

. 1901

. 0012

. 2188

. 0013

. 2779

. 0015

. 3360

. 0016

. 3929

. 0018

.4519

. 0019

1 See footnote 1 on page 12. 2 See footnote 2 on page 12.
6 NATIONAL SCREW THREAD COMMISSION

Table 15.

Limiting dimensions and tolerances, classes 1, 2, 8, and 4- fits, American National coarse-thread series—

Continued

Ha ft U 7A 1 m m

Threads per inch

19 20 21 22 BOLTS AND SCREWS

[Max__

Class 1, major diameter ^Min__

[To1___

{Max

Min

Tol

Class 2, major diameter [Max__

(threaded parts of unfin-jMin__

ished, hot-rolled material) [Tol

Class 1, minor diameter Max.1 -- Classes 2, 3, and 4, minor diameter Max.1 .. Class 1, loose fit, pitch di-{^[fx-- ameter [Tol

Class 2, free fit, pitch diam-fJJ^--

eter {Tol."

Class 3, medium fit, pitch/^fx -- diameter

ITol

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

ameter |Toi

" NUTS AND TAPPED HOLES

Classes 1, 2, 3, and 4, major diameter Min.2 __ Classes 1, 2, 3, and 4, minor} ^

x -- diameter

[Tol

Classes 1, 2, 3, and 4, pitch diameter Min__

Class 1, loose fit, pitch di-|Max__

ameter \Tol

Class 2, free fit, pitch diam-/Max__

eter \ToL__

Class 3, medium fit, pitch fMax__

diameter \Tol

Class 4, close fit, pitch di-/Max__

ameter \Tol

Inch

0. 5601

. 5443

. 0158

. 5625

. 5513

. 0112

. 5625

. 5467

. 0158

. 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. 6224

. 6054

. 0170

. 6250

. 6132

. 0118

. 6250

. 6080

. 0170

. 5109

. 5135

. 5634

. 5549

. 0085

. 5660

. 5601

. 0059

. 5660

. 5618

. 0042

. 5665

. 5644

. 0021

. 6250

. 5397

. 5266

. 0131

5660

5745

0085

5719 0059

5702 0042

5681 0021

Inch

0. 7472

. 7288

. 0184

. 7500

. 7372

. 0128

. 7500

. 7316

. 0184

. 6245

. 6273

. 6822

. 6730

. 0092

. 6850

. 6786

. 0064

. 6850

. 6805

. 0045

. 6856

. 6833

. 0023

7500

6553 6417

0136

6850

6942 0092

6914 0064

6895 0045

6873 0023

Inch

0. 8719

. 8519

. 0200

. 8750

. 8610

. 0140

. 8750

. 8550

. 0200

. 7356

. 7387

. 7997

. 7897

. 0100

. 8028

. 7958

. 0070

. 8028

. 7979

. 0049

. 8034

. 8010

. 0024

8750

7689 7547

0142

8028

8128 0100

8098 0070

8077

0049 8052

0024

Inch

0. 9966

. 9744

. 0222

1. 0000

. 9848

. 0152

L 0000

. 9778

. 0222

. 8432

. 8466

. 9154

. 9043

. 0111

. 9188

. 9112

. 0076

. 9188

. 9134

. 0054

. 9195

. 9168

. 0027

1. 0000

. 8795

. 8647

. 0148

9188

9299

0111 9264 0076

9242 0054

9215 0027

Inches

1. 1211

1. 0963

. 0248

1. 1250

1. 1080

. 0170

1. 2500

1. 1002

. 0248

. 9458

. 9497

1. 0283

1. 0159

. 0124 L 0322

1. 0237

. 0085

1. 0322

1. 0263

. 0059

1. 0330

1. 0300

. 0030

1. 1250

. 9858

. 9704

. 0154

1. 0322

1. 0446

. 0124

1. 0407

. 0085

1. 0381

. 0059

1. 0352

. 0030

Inches

1. 2461

1. 2213

. 0248

1. 2500

1. 2330

. 0170

1. 2500

1. 2252

. 0248

i. 0708

i. 0747

1. 1533

1. 1409

. 0124

I. 1572

1. 1487

. 0085

1. 1572

1. 1513

. 0059

1. 1580

1. 1550

. 0030

I. 2500

1. 1108

1. 0954

. 0154

1. 1572

1. 1696

. 0124

1. 1657

. 0085

1. 1631

. 0059

1. 1602

. 0030

1 See footnote 1 on page 12. 2 See footnote 2 on page 12.
DIMENSIONS OF STANDARD SCREW THREADS

Table 15.

Limiting dimensions and tolerances, classes 1, 2, 8, and J^fits, American National coarse-thread series—

Continued

Sizes m 2 2% 3 3

Threads per inch

5 m

'

4 4 4 3^

i U 25 26 27 28 29 30 BOLTS AND SCREWS

fMax__

< Min

Inches

1. 7448

1. 7110

Inches

1. 9943

1. 9575

laches

2. 2443

2. 2075

Inches

2. 4936

2. 4528

Inches

2. 7436

2. 7028

Inches

2. 9936

2. 9528

Inches

2. 9927

2. 9469

[Tol— . 0458 AOO O

. 0338 . 0368 . 0368 A A AO. 0408 A /< AO . 0408 . 0408

CilticcOQ 9 Q onrl 4. tyi q t <^\t* i o "m o"f or* fMax__

< Min

lTol__-

1. 7500

1. 7268

2. 0000

1. 9746

. UZ54

2. 2500

2. 2246

not;,)

2. 5000

2. 4720

. U280

2. 7500

2. 7220

3. 0000

2. 9720 AOOA . Uz80

3. 0000

2. 9686

. 0314

Class 2, major diameter (threaded

£><x.I- Uo UI Li111 IHJ.olXt?vIy 111? 1* I Ullt/U. ll±<a- terial) _ _ (Max__

J Min

[To1_~_~

1. 7500

1. 7162

A09C

2. 0000

1. 9632

f\oao

. Uouo

2. 2500

2. 2132

. Oooo

2. 5000

2. 4592

A/! AO

2. 7500

2. 7092

A/f AO . 04U8

3. 0000

2. 9592

A A AO

3. 0000

2. 9542

. 0458

Class 1, minor diameter _ _ _ __ Max.1 .. 1. 4994 1. 7217 1. 9717 2. 1869 2. 4369 2. 6869 2. 6421

Classes 2, 3, and 4, minor diameter. _ Max.1 . . 1. 5046 1. 7274 1. 9774 2. 1933 2. 4433 2. 6933 2. 6494

Class 1, loose fit, pitch diameter

fMax__

{Min..

iTol...

1. 6149

1. 5980

. 0169

1. 8500

1. 8316

. 0184

2. 1000

2. 0816

. 0184

2. 3312

2. 3108

. 0204

2. 5812

2. 5608

. 0204

2. 8312

2. 8108

. 0204

2. 8071

2. 7842

. 0229

Class 2, free fit, pitch diameter. _ _ fMax__

jMin__

1. 6201

1. 6085

1. 8557

1. 8430

2. 1057

2. 0930

2. 3376

2. 3236

2. 5876

2. 5736

2. 8376

2. 8236

2. 8144

2. 7987

ITol... . 0116 . 0127 . 0127 . 0140 . 0140 . 0140 . 0157

Class 3, medium fit, pitch diameter.

fMax__

{Min__

ITol—

1. 6201

1. 6119

. 0082

1. 8557

1. 8468

. 0089

2. 1057

2. 0968

. 0089

2. 3376

2. 3279

. 0097

2. 5876

2. 5779

. 0097

2. 8376

2. 8279

. 0097

2. 8144

2. 8037

. 0107

Class 4, close fit, pitch diameter

[Max..

{Min..

iTol...

1. 6211

1. 6170

. 0041

1. 8568

1. 8524

. 0044

2. 1068

2. 1024

. 0044

2. 3389

2. 3341

. 0048

2. 5889

2. 5841

. 0048

2. 8389

2. 8341

. 0048

2. 8160

2. 8107

. 0053

NUTS AND TAPPED HOLES

Classes 1, 2, 3, and 4, major diameter. Min.2 __ 1. 7500 2. 0000 2. 2500 2. 5000 2. 7500 3. 0000 3. 0000

Classes 1, 2, 3, and 4, minor diameter.

fMax__

Min__

Tol...

1. 5551

1. 5335

. 0216

I. 7835

1. 7594

. 0241

2. 0335

2. 0094

. 0241

2. 2564

2. 2294

. 0270

2. 5064

2. 4794

. 0270

2. 7564

2. 7294

. 0270

2. 7216

2. 6907

. 0309

Classes 1, 2, 3, and 4, pitch diameter. Min. . 1. 6201 1. 8557 2. 1057 2. 3376 2. 5876 2. 8376 2. 8144

Class 1, loose fit, pitch diameter /Max..

\Tol___

1. 6370

. 0169

1. 8741

. 0184

2. 1241

. 0184

2. 3580

. 0204

2. 6080

. 0204

2. 8580

. 0204

2. 8373

. 0229

Class 2, free fit, pitch diameter /Max..

ITol...

1. 6317

. 0116

1. 8684

. 0127

2. 1184

. 0127

2. 3516

. 0140

2. 6016

. 0140

2. 8516

. 0140

2. 8301 .0157

Class 3, medium fit, pitch diameter. /Max..

ITol...

1. 6283

. 0082

1. 8646

. 0089

2. 1146

. 0089

2. 3473

. 0097

2. 5973

. 0097

2. 8473

. 0097

2. 8251 .0107

Class 4, close fit, pitch diameter /Max..

ITol—

1. 6242

. 0041

1. 8601

. 0044

2. 1101

. 0044

2. 3424

. 0048

2. 5924

. 0048

2. 8424

. 0048

2. 8197

. 0053

1 See footnote 1 on page 12, 2 See footnote 2 on page 12. 60930°—29 2
8 NATIONAL SCREW THREAD COMMISSION

II. AMERICAN NATIONAL FINE-THREAD SERIES

The American National fine-thread series is recommended for general use in automotive

and aircraft work, for use where the design requires both strength and reduction in weight,

and where special conditions require a fine thread.

Table 2.

American National fine-thread series

Identification Basic diameters Thread data

Threads

per inch n Major

diameter D

80

72

645648

44

40

3632

2828

24

2420

20

18

18

16

14

14

1212

1210

10

Inches O 060

. 073

. 086

. 099

. 112

. 125

. 138

. 164

. 190

. 216

. 2500

. 3125

. 3750

. 4375

. 5000

. 5625

. 6250

. 7500

. 8750

1. 0000

1. 1250 L 2500

1. 5000

1. 7500

2. 0000

2. 2500

2. 5000

2. 7500

3. 0000

Pitch diameter E

Inches

0. 0519

. 0640

. 0759

. 0874

. 0985

. 1102

. 1218

. 1460

. 1697

. 1928

. 2268

. 2854

. 3479

. 4050

. 4675

. 5264

. 5889

. 7094

. 8286

. 9536

0709

1959 4459

1. 6850

1. 9350

1688 4188

6688

9188

Minor

diameter K

Metric

equivalent

of major

diameter

Inches

0. 0438

. 0550

. 0657

. 0758

. 0849

. 0955

. 1055

. 1279

. 1494

. 1696

. 2036

. 2584

. 3209

. 3725

. 4350

. 4903

. 5528

. 6688

. 7822

. 9072

1. 0167

1. 1417

1. 3917

1. 6201

1. 8701 0876

3376

5876 8376

mm

1. 524

1. 854

2. 184

2. 515

2. 845

3. 175

3. 505

4. 166

4. 826

5. 486

6. 350

7. 938

9. 525

11. 113

12. 700

14. 288

15. 875

19. 050

22. 225

25. 400

28. 575

31. 750

38. 100

44. 450

50. 800

57. 150

63. 500

69. 850

76. 200

Pitch P

Inch

0. 01250

01389

01562

01788

02083

02273

02500

02778

03125

03571

03571 04167

04167

05000

05000

05556

05556

06250

07143

07143

08333

08333

08333

10000

10000

12500 12500

12500

12500

Depth of thread

h

Inch

0. 00812

. 00902

. 01015

. 01160

. 01353

. 01476

. 01624

. 01804

. 02030

. 02320

. 02320

. 02706

. 02706

. 03248

. 03248

. 03608

. 03608

. 04059

. 04639

. 04639

. 05413

. 05413

. 05413

. 06495

. 06495

. 08119

. 08119

. 08119

. 08119

Basic width of

flat P/8

Inch

0. 00156

00174

00195

00223

00260

00284

00312

00347

00391 00446

00446

00521

00521 00625

00625

00694

00694

00781 00893

00893

01042

01042

01042

01250

01250

01562

01562

01562

01562

Minimum

width of

flat at major di- ameter of nut

p/24

Inch

0. 00052

. 00058

. 00065

. 00074

. 00087

. 00095

. 00104

. 00116

. 00130

. 00149

. 00149

. 00174

. 00174

. 00208

. 00208

. 00231

. 00231

. 00260

. 00298

. 00298

. 00347

. 00347

. 00347

. 00417

. 00417

. 00521

. 00521

. 00521

. 00521

Helix angle

at basic pitch di- ameter

s

23

57

45

43

5145

44

28

3 21

3 22

5240

1115

1 5755

4336

34

22

25

16

3

557

57

5147
DIMENSIONS OF STANDARD SCREW THREADS 9

Table 16.Limiting dimensions and tolerances, classes 1, 2, 3, and 4 fits, American National fine-thread series

Machine screw number

l 3 3 4 5 6

Threads per inch

80 72 64 * 56 48 44 40

1 2 3 4 5 6 7 8 BOLTS AND SCREWS

Max..

Class 1. major diameter _{ Min__

iTol—

Inch

0. 0593

. 0545

. 0048

Inch

0. 0723

. 0673

. 0050

Inch

0. 0853

. 0801

. 0052

Inch

0. 0982

. 0926

. 0056

Inch

0. 1111

. 1049

.. 0062

Inch

0. 1241

. 1177

. 0064

Inch

0. 1370

. 1302

. 0068

[Max..

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

iTol—

. 0600

. 0566

. 0034

. 0730

. 0694

. 0036

. 0860

. 0822

. 0038

. 0990

. 0950

. 0040

. 1120

. 1076

. 0044

. 1250

. 1204

. 0046

. 1380

. 1332

. 0048

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

. 0440

. 0447

. 0553

. 0560

. 0661

. 0668

. 0763

.0771

. 0855

.0864

. 0962

. 0971

. 1063

. 1073

C TV If ^ -FT Max. _ Class 1, pitch diameter {Min__

lTol___

. 0512

. 0488

. 0024

. 0633

. 0608

. 0025

. 0752

. 0726

. 0026

. 0866

. 0838

. 0028

. 0976

. 0945

. 0031

. 1093

. 1061

. 0032

. 1208

. 1174

. 0034

f Max. _ Class 2, pitch diameter \ Min__

ITol...

. 0519

. 0502

. 0017

. 0640

. 0622

.0018

. 0759

. 0740

. 0019

.0874

.0854

. 0020

. 0985

. 0963

. 0022

. 1102

. 1079

. 0023

. 1218

. 1194

. 0024

f Max. _ Class 3, pitch diameter I Min_ _ [Tol

. 0519

. 0506

. 0013

. 0640

.0627

. 0013

.0759

.0745

. 0014

. 0874

. 0859

. 0015

. 0985

. 0969

. 0016

. 1102

. 1086

. 0016

. 1218

. 1201

. 0017

[Max..

Class 4, pitch diameter \ Min_ - ITol—

. 0520

. 0514

. 0006

. 0641

. 0634

. 0007

. 0760

. 0753

. 0007

. 0876

. 0869

. 0007

. 0987

. 0979

. 0008

. 1104

. 1096

. 0008

. 1220

. 1211

. 0009

NUTS AND TAPPEiD HOLiil fc> Classes 1, 2, 3, and 4, major diameter. Min.2 . 0600 .0730 . 0860 . 0990 . 1120 . 1250 . 1380 [Max..

Classes 1, 2, 3, and 4, minor diameter.^ Mm. _ [Tol___

. 0492

. 0465

. 0027

. 0610

. 0580

. 0030

. 0724

. 0691

. 0033

. 0834

. 0797

. 0037

. 0937

. 0894

. 0043

. 1049

. 1004

. 0045

. 1158

. 1109

. 0049

Classes 1, 2, 3, and 4, pitch diameter. Mm. _ . 0519 . 0640 . 0759 . 0874 . 0985 . 1102 . 1218

Class 1, pitch diameter . |Max_

_

. 0543

. 0024

.0665

. 0025

. 0785

. 0026

. 0902

. 0028

. 1016

. 0031

. 1134

. 0032

. 1252 .0034

Class 2, pitch diameter {toT"

.0536

. 0017

. 0658

. 0018

.0778

. 0019

. 0894

. 0020

. 1007

. 0022

. 1125

. 0023

. 1242

. 0024

Class 3, pitch diameter {toI*'

. 0532

. 0013

. 0653

. 0013

. 0773

. 0014

. 0889

. 0015

. 1001 .0016. 1118

. 0016

. 1235

. 0017

Class 4, pitch diameter {tc?"

. 0525

. 0006

. 0647

. 0007

. 0766

. 0007

. 0881

. 0007

. 0993

. 0008

. 1110

. 0008

. 1227

. 0009

1 See footnote 1 on page 12, 2 3ee footnote 2 on page 12.
10 NATIONAL SCREW THREAD COMMISSION

Table 16.

Limiting dimensions and tolerances, classes 1, 2, 8, and 4 fits, American National fine-thread series- Continued

Machine screw number or nominal size

8 10 12 H Me %

Tlireads per inch

32 28 24

BOLTS AND SCREWS

[Max..

Class 1, major diameter \ Min_.

[Max..

Classes 2, 3, and 4, major diameter- - \ Min_.

|To1,_. Class 1, minor diameter Max.1 .. Classes 2, 3, and 4, minor diameter. Max.1 .

.

[Max..

Class 1, pitch diameter \ Min_.

lTol__.

{Max..

Min_

.

Tol__.

[Max..

Class 3, pitch diameter |Min_.

[Tol__.

[Max_.

Class 4, pitch diameter <Min_.

lTol__.

NUTS AND TAPPED HOLES

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

Classes 1, 2, 3, and 4, minor diameter I Min.

.

[Tol...

Classes 1, 2, 3, and 4, pitch diameter. Min_.

Class 1, pitch diameter {toT*"'

Class 2, pitch diameter {toT"

Class 3, pitch diameter --{toT*"

Class 4, pitch diameter {toT"

Inch

0. 1629

. 1557

. 0072

. 1640

. 1590

. 0050

. 1288

. 1299

. 1449

. 1413

. 0036

. 1460

. 1435

. 0025

. 1460

. 1442

. 0018

. 1462

. 1453

. 0009

. 1640

. 1391

. 1339

. 0052

. 1460

. 1496

. 0036

. 1485

. 0025

. 1478

. 0018

. 1469

. 0009

Inch

0. 1889

. 1813

. 0076

. 1900

. 1846

. 0054

. 1506

. 1517

. 1686

. 1648

. 0038

. 1697

. 1670

. 0027

. 1697

. 1678

. 0019

. 1699

. 1689 .0010

. 1900

1618

1562 0056

1697

1735 0038

1724 0027

1716 0019

1707 0010

Inch

0. 2148

. 2062

. 0086

. 2160

. 2098

. 0062

. 1710

. 1722

. 1916

. 1873

. 0043

. 1928

. 1897

. 0031

. 1928

. 1906

. 0022

. 1930

. 1919

. 0011

.2160

1833

1773 0060

1928

1971 0043

1959

0031 1950 0022

1939 0011

Inch

0. 2488

. 2402

. 0086

. 2500

. 2438

. 0062

. 2050

. 2062

. 2256

. 2213

. 0043

. 2268

. 2237

.0031

. 2268

. 2246

. 0022

. 2270

. 2259

. 0011

. 2500

. 2173

. 2113

. 0060

. 2268

. 2311

. 0043

. 2299

. 0031

. 2290

. 0022

. 2279

. 0011

Inch

0. 3112

. 3020

. 0092

. 3125

. 3059

. 0066

. 2601

. 2614

. 2841

. 2795

. 0046

. 2854

. 2821

. 0033

. 2854

. 2830

. 0024

. 2857

. 2845

. 0012

.3125

. 2739

. 2674

. 0065

. 2854

. 2900

. 0046

. 2887

. 0033

. 2878

. 0024

. 2866

.0012

Inch

0. 3737

. 3645

. 0092

. 3750

. 3684

. 0066

. 3226

. 3239

. 3466

. 3420

. 0046

. 3479

. 3446

. 0033

. 3479

. 3455

. 0024

.3482

. 3470

. 0012

. 3750

. 3364

. 3299

. 0065

. 3479

. 3525

. 0046

. 3512

. 0033

. 3503

. 0024

. 3491

. 0012

1 See footnote 1 on page 12. 2 See footnote 2 on page 12,
DIMENSIONS OF STANDARD SCREW THREADS H

Table 16.

Limiting dimensions and tolerances, classes 1, 2, 3, and 4 fits, American National fine-thread series—

Continued

Sizes

Y* % % l W

Threads per inch

20 18 18 16 * 14 14 12 12

1 16 17 18 19 20 21 22 23 BOLTS AND SCREWS

[Max__

Class 1, major diameter \ Min__

[Tol

Inch

0. 4985

. 4883

. 0102

Inch

0. 5609

. 5495

. 0114

Inch

0. 6234

. 6120

. 0114

Inch

0. 7482

. 7356

. 0126

Inch

0. 8729

. 8589

. 0140

Inch

0. 9979

. 9839

. 0140

Inches

1. 1226

1. 1068

. 0158

Inches

1. 2476

1. 2318

. 0158

f Max

Classes 2, 3, and 4, major di-l -^.^ ameter _ _ _ _

j rpQj

. 5000

. 4928

. 0072

. 5625

. 5543

. 0082

. 6250

. 6168

. 0082

. 7500

. 7410

. 0090

. 8750

. 8652

. 0098

1. 0000

. 9902

. 0098

1. 1250

1. 1138

. 0112

1. 2500

1. 2388

. 0112

Class 1, minor diameter Max.1 .. Classes 2, 3, and 4, minor di- ameter. _ Max.1 .

. 4372

. 4387

. 4927

. 4943

. 5552

. 5568

. 6715

. 6733

. 7853

. 7874

. 9103

. 9124

1. 0204

1. 0228

1. 1454

1. 1478 [Max..

Class 1, pitch diameter { Min__

[Tol___

. 4660

. 4609

! 0051

. 5248

. 5191

! 0057

. 5873

. 5816

. 0057

. 7076

. 7013

! 0063

. 8265

. 8195

! 0070

. 9515

. 9445

! 0070

1. 0685

1. 0606

'. 0079

1. 1935

1. 1856

'. 0079

[Max..

Class 2, pitch diameter <Min__

[Tol...

. 4675

. 4639

. 0036

. 5264

. 5223

. 0041

. 5889

. 5848

. 0041

. 7094

. 7049

. 0,045

. 8286

. 8237

. 0049

. 9536

. 9487

. 0049

1. 0709

1. 0653

. 0056

1. 1959

1. 1903

. 0056

[Max..

Class 3, pitch diameter I Min__

IToL__

. 4675

'. 4649

. 0026

. 5234

. 0030

. 5889

! 5859

. 0030

. 7094

1 7062

. 0032

. 8286

! 8250

. 0036

. 9536

.' 9500

. 0036

1. 0709

1. 0669

. 0040

1. 1959

1. 1919

. 0040

[Max..

Class 4, pitch diameter \ Min__

[Tol...

. 4678

. 4665

. UUlO

. 5267

. 5252

nni ^ . UUlO

. 5892

. 5877

. nni UUXQK

. 7098

. 7082

. 0016

. 8290

. 8272

. 0018

. 9540

. 9522

. 0018

1. 0714

1. 0694

1. 1964

1. 1944 0090

NUTS AND TAPPED HOLES

Classes 1, 2, 3, and 4, major

diameter. _ Min.2 _ . 5000 . 5625 . 6250 . 7500 . 8750 1. 0000 1. 1250 1. 2500

„ 1 o o „ „ j a „„ f -IVlax

Classes 1, 2, 6, and 4, minor 1 jyjj n

diameter --|Tol

. 4531

. 4459

. 0072

. 5100

. 5024

. 0076

. 5725

. 5649

. 0076

. 6903

. 6823

. 0080

. 8062

. 7977

. 0085

. 9312

. 9227

. 0085

1. 0438

1. 0348

. 0090

1. 1688

1. 1598

. 0090

Classes 1, 2, 3, and 4, pitch

diameter. _ __Min__ . 4675 . 5264 . 5889 . 7094 . 8286 . 9536 1. 0709 1. 1959

Class 1, pitch diameter {toI*

-- . 4726

. 0051

. 5321

. 0057

. 5946

. 0057

.7157

. 0063

.8356

. 0070

. 9606

. 0070

1. 0788

. 0079

1. 2038

.0079

_<i , . f ]VTa,x Class 2, pitch diameter lTol

~~ . 4711

. 0036

. 5305

. 0041

. 5930

. 0041

. 7139

. 0045

.8335

. 0049

.9585

. 0049

1. 0765

. 0056

1. 2015

.0056

Class 3, pitch diameter {toI*"

. 4701

. 0026

. 5294

. 0030

. 5919

. 0030

. 7126

. 0032

. 8322

. 0036

. 9572

. 0036

1. 0749

. 0040

1. 1999 .0040

Class 4, pitch diameter {toT^

- . 4688

. 0013

. 5279

. 0015

. 5904

. 0015

. 7110

. 0016

.8304

. 0018

. 9554

. 0018

1. 0729

. 0020

1. 1979

. 0020

1 See footnote 1 on page 12. 2 See footnote 2 on page 12.
12 NATIONAL SCEEW THEEAD COMMISSION

Table 16.

Limiting dimensions and tolerances, classes 1, 2, S, and 4 fits, American National fine-thread series—Con.

Sizes 2H

Threads per inch

2H 2H

25 27 29 BOLTS AND SCREWS

fMax__

Class 1, major diameter <Min__

lTol___

[Max__

ses 2, 3, and 4, major diameter. _^ Min__

[Tol___

Class 1, minor diameter Max.1 -- Classes 2, 3, and 4, minor diameter.- Max.1 .- [Max__

Class 1, pitch diameter ^Min__

[Tol___

[Max..

Class 2, pitch diameter <Min__

lTol___

[Max__

Class 3, pitch diameter \ Min_ _ [To1_._

[Max__

Class 4, pitch diameter \ Min_ _ [To1___

NUTS AXD TAPPED HOLES

Classes 1, 2, 3, and 4, major diameter. Min.2 __ [Max..

Classes 1, 2, 3, and 4, minor diameterJ Min. _ ITo1___

Classes 1, 2, 3; and 4. pitch diameter, Min

Class 1, pitch diameter {to**"

Class 2, pitch diameter {toT""

Class 3, pitch diameter {to**"

Class 4, pitch diameter {to*"

Inches

1. 4976

1. 4818

. 0158

1. 5000

1. 4888

. 0112

1. 3954

L 3978

1. 4435

1. 4356

. 0079 4459

4403

0056 4459

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 L 7472

1. 7288

. 0184

1. 7500

1. 7372

. 0128

1. 6245

1. 6273

1. 6822

1. 6690

. 0132

1. 6850

1. 6750

. 0100

1. 6850

1. 6766

. 0084

1. 6856

1. 6814

. 0042

1. 7500

1. 6525

1. 6417

. 0108

1. 6850

1. 6982

. 0132

1. 6950

. 0100

1. 6934

. 0084

1. 6892

. 0042

Inches

1. 9972

1. 9788

. 0184

2. 0000

1. 9872

. 0128

1. 8745

1. 8773

1. 9322

1. 9190

. 0132

1. 9350

1. 9250

. 0100

1. 9350

1. 9266

. 0084

1. 9356

1. 9314

. 0042

2. 0000

1. 9025

1. 8917

. 0108

1. 9350

1. 9482

. 0132

1. 9450

. 0100

1. 9434

. 0084

1. 9392

. 0042

Inches

2. 2466

2. 2244

. 0222

2. 2500

2. 2348

. 0152

2. 0932

2. 0966

2. 1654

2. 1509

. 0145

2. 1688

2. 1578

. 0110

2. 1688

2. 1596

. 0092

2. 1695

2. 1649

. 0046

2. 2500

2. 1282

2. 1147

. 0135

2. 1688

2. 1833

. 0145

2. 1798

. 0110

2. 1780

. 0092

2. 1734

. 0046

Inches

2. 4966

2. 4744

. 0222

2. 5000

2. 4848

. 0152

2. 3432

2. 3466

2. 4154

2. 4009

. 0145 4188

4078

0110

4188

4096

0092 4195

4149

0046

2. 5000

2. 3782

2. 3647

. 0135

2. 4188

2. 4333

. 0145

2. 4298

. 0110

2. 4280

. 0092

2. 4234

. 0046

Inches

2. 7466

2. 7244

. 0222

2. 7500

2. 7348

. 0152

5932

5966 6654

6509

. 0145

2. 6688

2. 6578

. 0110

6596

0092

6695 6649

0046

2. 7500

2. 6282

2. 6147

. 0135

2. 6688

2. 6833

. 0145

2. 6798

. 0110

2. 6780

. 0092

2. 6734

. 0046

1 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 corresponding to a fiat at the minor diameter of the minimum screw equal to ){X p, and may be determined

by subtracting the basic thread depth, h (or 0.6495 p), from the minimum pitch diameter of the screw.

2 Dimensions for the minimum major diameter of the nut correspond to the basic flat (}£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 lit Xp, and may be determined by adding V/tXh (or 0.7939 p) to the maximum pitch diameter of the nut.
DIMENSIONS OF STANDAED SCREW THREADS 13

III. APPENDIX

TAP DRILL SIZES

Table 107.Sizes of tap drills, American National coarse-thread series

Minor diameter of nut

Threads

per inch

Basic

64

56

48

40

40

32

32

24

24

20

18

16

14

Inch

0. 0527

. 0628

. 0719

. 0795

. 0925

. 0974

. 1234

. 1359

. 1619

. 1850

. 2403

. 2938

.3447

Maximum

Inch

0. 0604

. 0715

. 0820

. 0913

. 1043

. 1118

. 1378

. 1541

. 1801

. 2060

. 2630

.3184

.3721

Minimum

Inch

0. 0561

. 0667

. 0764

. 0849

. 0979

. 1042

. 1302

. 1449

. 1709

. 1959

. 2524

.3073

. 3602

Stock drills within limits on minor diameter of nut Numbered and fractional-inch sizes

Nominal size

No. 53. No. 51. No. 50.

' b/U inch. No. 47

_

No. 46_ No. 45 _ No. 44. No. 43.

No. 40. No. 39. No. 38. No. 37. No. 36_

Yu inch. No. 35_ No. 34_ No. 29.

No. 26. No. 25. No. 24. No. 23. '% inch. No. 17_. No. 16_. No. 15 No. 9___ No. 8___ No. 7___

1 %i inch. No. 6___ No. 5___

Yiq inch. .0U.

Diameter

Inch

0. 0595

. 0670

. 0700

. 0781

. 0785

. 0810

. 0820

. 0860

. 0890

. 0980

. 0995

. 1015

. 1040

. 1065

. 1094

. 1100

. 1110

. 1360

. 1470

. 1495

. 1520

. 1540

. 1719

. 1730

. 1770

. 1800

. 1960

. 1990

. 2010

. 2031

. 2040

. 2055

. 2570

. 2610

. 3125

. 3160

. 3680

Per cent of depth of basic thread

67

82

69

77

76

67

6380

71

837972

657870

69

67

69

79

7570

67

81

7972

67

83

79

7572

716977

7177

73

75

Metric sizes

Nominal

size

mm

1. 5 1.7

1. 75

1. 8

2.

Diameter

2. 7

2. 75

2. 8

3. 4

3. 5

3. 7

3. 75

3. 8

3. 9

4. 4

4. 5

5.

5. 1 5.2

6.5 6.6

7. 9

8.

9. 2

9. 25

9. 3

9. 4

Inch

0. 0591

. 0669

. 0689

. 0709

. 0787

0866

0886

0906

0984

1024

1063

1083 1102

1339

1378 1457

1476

1496

1535 1732

1772

1968 2008

2047

2559

2598

3110

3150

3622

3642

3661

3701

Per cent of depth of basic thread
14 NATIONAL SCREW THREAD COMMISSION

Table !l07.

Sizes of tap drills, American National coarse-thread series—Continued

Size of thread

%-

k-

%-

i_.

1M

VA

m

2_.

3..

.

Threads

per inch

13

12

1110

9

4/2

4

4

4

Minor diameter of nut

Basic

Inches

0. 4001

. 4542

. 5069

. 6201

. 7307

. 8376

. 9394 i 0644

1. 2835

1. 4902

l[ 7113 I 9613

2. 1752

2. 4252

2. 6752

2. 6288

Maximum

Inches

0. 4290

. 4850

. 5397

. 6553

. 7689

. 8795

. 9858

1. 1108

1. 3376

1. 5551

1. 7835

2. 0335

2. 2564

2. 5064

2. 7564

2. 7216

Minimum

Inches

0. 4167

. 4723

. 5266

. 6417

. 7547

. 8647

. 9704

1. 0954

1. 3196

1. 5335

1. 7594

2. 0094

2. 2294

2. 4794

2. 7294

2. 6907

Stock drills within limits on minor diameter of nut Numbered and fractional-inch sizes

Nominal size

2 }U inch.

31/u inch. % inch.

7/s inch

6 %t inch V/u inches 1% inches-

_

l

35/u inches, _

1

4 %4 inches.

l

25

/z2 inches. f2%4 inches-.

\2y32 inches.

(2 15/U inches.

12^4 inches.

_

r2 3 ^64 inches.

_

inches

'2 4 %4 inches. 2% inches.

_

/24 %4 inches. 12% inches.

Diameter

Inches

0. 4219

. 4844

. 5312

. 7656

. 8750

. 9844

1. 1094

1. 3281

1. 5469

7656 7812

0156

0312

2344 2500

4844

5000

7344

7500

7031 7188

Per cent of depth of basic thread

78

72

7976

77

76

76

79

78

8176

817682

77

8277

82

7780

76

Metric sizes

Nominal

size

12.

13. 5

16. 5

19. 5

22.

25.

28.

39.

39. 5

45.

51. 5

57.

63.

63. 5

69. 5

70. 68. 5

69.

Diameter

Inches

0. 4724

. 5315

. 6496

. 7677

. 8661

. 9842

1. 1024

1. 5354

1. 5551

1. 7716

2. 0276

2. 2441

2. 4803

2. 5000

2. 7362

2. 7559

2. 6968

2. 7165

Per cent of depth of* basic thread

83

7977

7482

7680

83

75

79

77

79

83

77

8175

82

76
DIMENSIONS OF STANDAED SCREW THREADS

Table 108.—Sizes of tap drills, American National fine-thread series 15

Threads

per inch

80

72

6456

48

44

40

36

32

28

28

24

24

20

20

18

18

1614

14

12

12

1210

10

Minor diameter of nut

Basic

Inches

0. 0438

. 0550

. 0657

. 0758

. 0849

. 0955

. 1055

. 1279

. 1494

. 1696

. 2036

. 2584

. 3209

. 3725

. 4350

. 4903

. 5528

. 7822

. 9072

1. 0167

1. 1417

1. 3917

1. 6201

1. 8701

2. 0876

2. 3376

2. 5876

2. 8376

Maximum

Inches

0. 0492

0610

0724

0834

0937

1049

1158

1391

1618

1833

2173

2739

3364

3906

. 4531

. 5100

. 5725

. 6903

. 8062

. 9312

1. 0438

1. 1688

1. 4188

1. 6525

1. 9025

2. 1282

2. 3782

2. 6282

2. 8782

Minimum

Inches

0. 0465

. 0580

. 0691

. 0797

.0894

. 1004

. 1109

. 1339

. 1562

. 1773

. 2113

. 2647

. 3299

. 3834

. 4459

. 5024

. 5649

. 6823

. 7977

. 9227

1. 0348

1. 1598

1. 4098

1. 6417

1. 8917

2. 1147

2. 3647

2. 6147

2. 8647

Stock drills within limits on minor diameter of nut Numbered and fractioual-inch sizes Metric sizes

Nominal size

No. 56__ %4 inch__ No. 53. No. 50. /No. 46.

I No. 45. j%2 inch. \No. 42_

/No. 38. \No. 37. /No. 34.

I No. 33. (No. 29.

Yz2 inch. No. 22_ No. 21 _ No. 20

_

/No. 15. \No. 14. No. 3_.

IT.

W2 %4 inch.

inch.

}{& inch. 0)

0)

2y$ inches.

2%, inches. 2% inches.

2}i inches.

Diameter

Inches

0. 0465

. 0469

. 0595

. 0700

. 0810

. 0820

. 0938

. 0935

. 1015

. 1040

. 1110

. 1130

. 1360

. 1562

. 1570

. 1590

. 1610

. 1800

. 1820

. 2130

2720

3320

3860

3906

4531 5062

6875

0)

0)

2. 1250

2. 3750

2. 6250

2. 8750

Per cent of depth of basic thread

83

8175

79

787367

6880

718377

78

83

8176

7178

73

80

75

79

79

72

72

78

77

0)

C) 77

77

7777

Nominal

size

mm

1. 2

1. 25

1. 5

1. 8

2. 1

2. 3

2. 9

3. 4

3. 5

4.4. 1

4. 6

5. 4

5. 5

6. 9

8. 4

8. 5

9. 75

9. 8

9. 9

11. 5

14. 5

17. 5

23. 5

26. 5

29. 5

36.0)

0)

54,

66. 5

73.

Diameter

Inches

0. 0472

. 0492

. 0591

. 0709

. 0827

0906

1024

1142

1339 1378

1$75 1614

1811

. 2126

. 2165

. 2677

. 2717

. 3307

. 3346

. 3839

. 3858

. 3898

. 4528

. 5709

. 6890

(0

. 9252

1. 0433

1. 1614

1. 4173

0)

2. 1260

2. 6181

2. 8740

1 No standard size. o

#J