Errata to ASME B1.10M-1997 Unified Miniature Screw Threads

Errata to

ASME B1.10M-1997 Unified Miniature Screw Threads

On page 6, in Table 2, under the fifth column heading Height, 0.661H = 0.57259074P, the eighth and ninth entries were corrected to read O. 12883 and O. 143 15, respectively. The complete Table appears on the overleaf.

JANUARY 1998 THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS

345 East 47th Street, New York, NY 10017 II 111 N2597E 111 II IlIl Il COPYRIGHT American Society of Mechanical EngineersLicensed by Information Handling ServicesCOPYRIGHT American Society of Mechanical EngineersLicensed by Information Handling Services

TABL

E 2

THRE

AD

FORM

DI

MEN

SIO

NS,’

BASI

C AN

D DE

SIG

N

Pitc

h P

0.08

0 0.

090

0.10

0 0.

125

0.15

0

Heig

ht

of

ShwP

v.

H=

0.

6660

2540

P

0.08

928

0.07

794

0.08

660

0.10

825

0.12

990

Heig

ht

of

Dede

ndum

In

tern

al of

Int

ern8

1 Th

read

an

d Th

read

an

d De

pth

of

Adde

ndum

Th

read

of

Exte

rnal

Entm

mm

t Th

rwd.

6.5

64H

= 6.3

75H

= 0.4

8oO6

wOP

0324

7595

3P

0.03

840

0.02

598

0.04

320

0.02

923

0.04

600

0.03

248

0.06

000

0.04

059

0.07

200

0.04

871

Heig

ht,

Flat

at

Cres

t, Ra

dius

at

0.

661

H =

F,

= Ro

ot,

r, =

0572

5907

4P

0.12

5OOO

OOP

0.18

5181

49P

0.04

581

0.01

00

0.01

5 0.

0515

3 0.

0113

0.

017

0.05

728

0.01

25

0.01

9 0.

0715

7 0.

0156

0.

023

0.08

589

0.01

88

0.02

8

Roun

ded

Root

He

ight

, 0.5

66H

= 0.

5150

843g

P

0.04

129

0.02

57

0.00

6 0.

0464

5 0.

0289

0.

006

0.05

161

0.03

21

0.00

7 0.

0645

1 0.

0401

0.

009

0.07

741

0.04

81

0.01

1

0.17

5 0.

1515

5 0.

0840

0 0.

0568

3 0.

1002

0 0.

0219

0.

032

0.20

9 0.

1732

1 0.

0960

0 0.

0649

5 0.

1145

2 0.

0250

0.

037

0.22

5 0.

1949

6 0.

1080

0 0.

0730

7 0.

1288

3 0.

0281

0.

042

0.25

0 0.

2185

1 0.

1200

0 0.

0811

9 0.

1431

5 0.

0313

0.

046

0.30

0 0.

2598

1 0.

1440

0 0.

0974

3 0.

1717

8 0.

0375

0.

056

GENE

RAL

NOTE

: Fo

r sta

ndsrd

izatio

n,this

Ta

ble

of thr

ead

value

s ha

s be

en

estab

lishe

d ba

sed

on

a fun

ction

of

pitch

, /?

The

threa

d va

lues

base

d on

a

functi

onal

heigh

t, H,

are

us

ed

as

refer

ence

on

ly.

0.09

031

0.10

322

0.11

612

0.12

902

0.15

483

Bask

Thre

adFo

rm

Exte

rnal

Thre

ad

Desig

n Fo

rm

l- In

tern

al Th

read

De

sign

Form

Di

men

sions

. m

m

NOTE

: (1)

Fo

r inc

h co

nver

sion

of Ta

ble

2,see

Appe

ndix

6.

Flat

at

Cres

t, Ra

dius

at

F,

= Ro

ot

r, =

0.33

6743

74P

0.07

2166

78P

0.05

61

0.01

3 0.

0641

0.

014

0.07

22

0.01

6 0.

0802

0.

018

0.09

62

0.02

2

COPYRIGHT American Society of Mechanical EngineersLicensed by Information Handling ServicesCOPYRIGHT American Society of Mechanical EngineersLicensed by Information Handling Services


A N A M E R I C A N N A T I O N A L S T A N D A R D

ASME B1.l OM-1 887 (Revision of ASA B1.lO-1958)


~

STD-ASME B L - L O M - E N G L L797 I 0757b70 0583030 22b O

Date of Issuance: September 2, 1997

This Standard will be revised when the Society approves the issuance of a new edition. There will be no addenda or written interpretations of the requirements of this Standard issued to this edition.

ASME is the registered trademark of The American Society of Mechanical Engineers.

This code or standard was developed under procedures accredited as meeting the criteria for American National Standards. The Consensus Committee that approved the code or standard was balanced to assure that individuals from competent and concerned interests have had an opportunity to participate. The proposed code or standard was made available for public review and comment which provides an opportunityfor additional public input from industry, academia, regulatory agencies, and the public-at-large.

ASME does not "approve," "rate," or "endorse" any item, construction, proprietary device, or activity.

ASME does not take any position with respect to the validity of any patent rights asserted in connection with any items mentioned in this document, and does not undertake to insure anyone utilizing a standard against liability for infringement of any applicable Letters Patent, nor assume any such liability. Users of a code or standard are expressly advised that the determination of the validity of any such patent rights, and the risk of the infringement of such rights, is entirely their own responsibility.

Participation by federal agency representativeb) or personb) affiliated with industry is not to be interpreted as government or industry endorsement of this code or standard.

ASME accepts responsibilityforonly those interpretations issued in accordance with governing ASME procedures and policies which preclude the issuance of interpretations by individual volunteers.

No part of this document may be reproduced in any form, in an electronic retrieval system or otherwise,

without the prior written permission of the publisher.

The American Society of Mechanical Engineers 345 East 47th Street, New York, NY 10017

Copyright Q 1997 by THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS

All Rights Reserved Printed in U.S.A.


(This Foreword is not part of ASME B1.10M-1997.)

The standardization of threads for miniature fastening screws and similar purposes has been under study since 1927, when the National Screw Thread commission prepared a compilation of the practices of American manufacturers and various foreign standards. The latter included the Swiss standard NHS 56100, which first appeared in 1923. However, for want of sufficient interest, no further action was taken in the United States until 1943, when the demands of modem warfare awakened both the need for domestic standardization and the desirability of international standardization, particularly among the inch-using countries. For the consideration of this dual problem, together with other thread matters confined principally to the instrument industry, the American Standards Association established, in 1944, ASA War Committee B1.7 on Instrument Screw Threads.

The first significant progress toward standardization and unification of miniature threads was achieved at the American-British-Canadian Conference on the Unification of Engineering Standards held in Ottawa in 1945, when the delegations of these three countries joined in recommending the adoption of the NHS thread series in the size range of 0.30 mm to 0.90 mm having a 50 deg thread angle, and the development of a series closely following the NHS series for sizes larger than 0.90 mm with a 60 deg thread angle.

In June 1946 the War Committee was converted to Subcommittee No. 4 on Instrument Screw Threads of ASME Sectional Committee B1, Shortly thereafter it was learned that Swiss manufacturers were not adhering entirely to NHS 56100, but that the 60 deg thread angle made essentially in accordance with the Unified Thread Form was being widely used for the sizes below 1 mm. From this information and the results of subsequent experimental work by watch and instrument manufacturers both here and abroad, there developed a consensus favoring the 60 deg thread angle for all sizes.

At a meeting in June 1952 of Technical Committee No. 1, Screw Threads, of the International Organization for Standardization, a diameter-pitch series covering the range from 0.25 mm to 1.40 mm was adopted for recommendation to all national standardizing bodies. The Committee also agreed that further studies should be made regarding the use of the IS0 Basic Profile (or Unified Thread Form) in this range.

In the United States, where subsequent studies revealed no need, either current or anticipated, for sizes below 0.30 mm, it was established that the 60 deg angle for all sizes was feasible. It was also determined that the minor diameter of internal threads must be, and invariably is, kept above the minimum value established by the Unified Thread Form to avoid excessive tapping difficulties. From this conclusion and the calculation problems presented by the need for dimensioning this Standard in both metric and inch units, a simple plan evolved based on the coefficient of 0.52 in place of 0.54127 for basic thread height. These findings resulted in the formulation of the following recommendations by Subcommittee No. 4. for the American standard:

(a) that the series consist of all sizes from 0.30 mm to 1.400 mm in the IS0 recommendation; (b) that the 60 deg thread angle be adopted over the entire range; (c ) that the design thread forms be based on the simplified value of 0.52P, instead of

0.54127P, for the basic thread height.

... 111


The American views were presented at both the American-British-Canadian Conference in April 1955 and the plenary session of IS0 in June 1955. The latter session developed Draft IS0 recommendation No. 84 covering a metric series from 0.25 mm to 5.00 mm, with the I S 0 Basic Thread Profile, having a 60 deg angle and a thread height of 0.54 l27P, applied over the entire range.

American sentiment was strongly in favor of the simplified coefficients for the thread sizes 1.400 mm and below, and the previous issue of this Standard was formulated to incorporate the original American recommendation on thread height. Despite this deviation, complete interchangeability with product made to I S 0 recommendation No. 84 was regarded as a certainty in view of common practice on internal threads.

Tolerances given in this Standard were entirely of national origin, as recommendations on this phase had not yet been formulated by other bodies.

A preliminary draft of this Standard, approved by Subcommittee No. 4 on June 12, 1956, was distributed to industry for comment and criticism in October 1956. This draft was then revised and submitted to the Sectional Committee B1 for letter ballot in April 1957. In response to comments received with the letter ballot, the draft was further modified at a meeting of Subcommittee No. 4 on March 6, 1958. Following the acceptance of these modifications by the Sectional Committee, the proposal was submitted to and approved by the sponsor organizations and ASA. and was formally designated as an American Standard on August 18, 1958.

This Standard remained virtually unchanged from 1958 to 1995, while the use of miniature threads diminished considerably due to electronic components, replacing many of the mechanical devices used in watches and instrumentation. There still remains, however, an active use of miniature screw threads in spacecrafts and aircrafts, as components are miniaturized for weight considerations. Attempts were made to revise the Standard between 1979 and 1983, but unresolved negative votes defeated the proposed revisions. Efforts to revise the Standard were undertaken again in 1989.

The current Standard now has a thread height of 0.554H (0.48P), which is in agreement with FED-STD-H28/5 and ISO/R1501, and which allows for interchangeability with threads produced to the previous standard ASA BI. 10-1958. The dimensions and symbology are in line with current screw thread practices. This revision of Unified Miniature Screw Threads lists all dimensions in metric units. Inch conversions of these values have been placed i n the Appendix Section of this Standard.

ASME B1.10M-1997 was approved by the American National Standards Institute on July 11. 1997.

iv


ASME STANDARDS COMMITTEE B I Standardization and Unification of Screw Threads

(The following is the roster of the Committee at the time of approval of this Standard.)

OFFICERS

A. D. Shepherd, Jr., Chair G. L. Fechter, Secretary

COMMITTEE PERSONNEL

J. R. Anderson, Delphi Harrison Thermal System, Lockport, New York J. M. Bobelak, McDonnell Douglas Corp., St. Louis, Missouri R. M. Byrne, Trade Association Management, Inc., Tarrytown, New York D. P. Cadieux, Glastonbury Gage, Glastonbury, Connecticut F. G. Calderone, Quality Systems Implementers, Troy, Ohio L. N. Dixon, Jr., General Electric, Cincinnati, Ohio R. Dodge, Pennoyer-Dodge Co., Glendale, California A. E. Ellis, Consultant, Bedford, Massachusetts R. E. Ferry, Jr., R. B. &W, Caraopolis, Pennsylvania G. A. Flannery, Mercury Gage Co., Detroit, Michigan H. N. Frost, Defense Industrial Supply Ctr., Philadelphia, Pennsylvania D. S. George, Ford Motor Co., Dearborn. Michigan J. R. Gervasi, Kerr Lakeside, Inc., Euclid, Ohio J. Greenslade, Greenslade & Co., Fort Worth, Texas L. C. Johnson, The Johnson Gage Co., Bloomfield, Connecticut S. I. Kanter, Hanson-Whitney Co., Hartford, Connecticut R. P. Knittel, Leitech/AMTMA, Madison, Wisconsin J. A. Krippes, Pensacola, Florida R. S. Lanier, Consultant, Naples, Florida K. E. McCullough, Consultant, Willow Grove, Pennsylvania D. Miskinis, Greenfield Industries, Evans, Georgia W. R. Newman, Nylock Fastener Corp., Macomb, Michigan M. W. Rose, I T W Southern Gage Co., Erin, Tennessee G. A. Russ, Cummins Engine Co., Columbus, Indiana R. J. Sabatos, Cleveland Twist Drill Co., Asheboro, North Carolina D. M. Satava, Chagrin Falls, Ohio E. Schwartz, Consultant, Philadelphia, Pennsylvania R. H. Searr, Quantum Insp. and Testing Ltd., Burlington, Ontario, Canada R. E. Seppey, Laporte, Indiana V. B. Shook, Teledyne Landis Machine, Waynesboro, Pennsylvania A. G. Strang, Consultant, Boyds, Maryland R. D. Strong, General Motors Corp., Warren, Michigan J. F. Sullivan, National Fasteners Distr. Assoc., South Boston, Massachusetts R. L. Tennis, Caterpillar, Inc., Mossville, Illinois A. F. Thibodeau, Swanson Tool Mfg., Inc., West Hartford, Connecticut C. J. Wilson, Industrial Fasteners Inst., Cleveland, Ohio

V


SUBCOMMITTEE 10 - MINIATURE SCREW THREADS

A. D. Shepherd, JI., Chair, Northborough, Massachusetts J. M. Bobelak, McDonnell Douglas Corp., St. Louis, Missouri F. G. Calderone, Quality Systems Implementers, Troy, Ohio A. E. Ellis, Consultant, Bedford, Massachusetts D. M. Satava, Consultant, Chagrin Falls, Ohio

vi


CONTENTS

Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Standards Committee Roster . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 .1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 Unified Miniature Screw Thread Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.3 Designation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.4 Reference Documents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5 Acceptability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Screw Thread Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 Basic Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3 Design Profiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4 Lead . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5 Nominal Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.6 Classifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.7 Tolerance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.8 Coated Threads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.9 Limits of Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figures 1 Basic Profile for the UNM Screw Threads ........................................ 2 Design (Maximum Material) Thread Forms ........................................ 3 Disposition of Tolerances and Crest Clearances .................................... Tables 1 Thread Form Formulas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Thread Form Dimensions, Basic and Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Thread Size Formulas, Basic and Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Thread Size Dimensions, Basic and Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Tolerance Formulas for Limits of Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Limits of Size and Tolerances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Appendices A Gages and Gaging for Unified Miniature Screw Threads . . . . . . . . . . . . . . . . . . . . . . . . . . . B Inch Conversion of Table 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C Inch Conversion of Table 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D Inch Conversion of Table 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

... 111

V

2 2 2 2 2 2 2 2 3 3

3 4

I I

5 6 7 8 9

10

13 15 17 19

vii


ASME B1.10M-1997

UNIFIED MINIATURE SCREW THREADS

1 GENERAL ANSUASME B I .7M,* Nomenclature, Definitions, and Letter Symbols for Screw Threads

1.1 Scope Publisher: The American Society of Mechanical Engi- neers, 345 East 47th Street, New York, NY 10017 This Standard specifies the thread form, series, toler-

ance, and designation for the Unified Miniature Screw Is0 68, Is0 General Purpose Screw Threads Threads. The series covers a diameter range of 0.30 1 ~ 0 / ~ 1 5 0 1 , ISO Miniature screw Threads

mm to extending the “Profile and Publisher: International Organization for Standardiza- unified thread series that begin at 1.6 mm. tion, 3 rue de Varembe, 121 1 Geneva 20, Switzerland

1.2 Unified Miniature Screw Thread Standards

The fourteen sizes published in this Standard were endorsed by the American-British-Canadian conference of April 1955 as the basis of the unified standard among inch-using countries, and to correspond with the range of sizes in the ISO. The sizes are shown in Table 4. In interest of standardization and where design permits, selection of size should be confined to those indicated in bold type in Table 4. For more restrictive conditions, those sizes indicated in regular type in Table 4 may be used.

1.3 Designation

Unified Miniature Thread sizes of this series shall be designated on engineering drawings, in specifications, and on tools and gages (space permitting) by their nominal diameter in hundredths of a millimeter followed by the symbol “UNM” (e.g., 0.80 UNM).

On internal threads, the ful l limits of minor diameter, as given in Table 6, shall normally be considered applicable. Where this is not permissible, the designation shall be supplemented by the minor diameter limits.

1.4 Reference Documents’

The latest issues of the following documents form a part of this Standard to the extent specified herein.

1.5 Acceptability

1.5.1 Additional recommended methods for determining the acceptability of miniature screw threads will be included as further experience with this thread standard is reported. Until such time, agreements must be reached between purchaser and vendor regarding the basis for determining acceptance, since practices are likely to differ considerably, particularly for external threads. Where a free choice is possible, the procedures given below, which are being used with considerable success by some producers, are suggested.

1.5.2 External Threads. The major diameter of the external thread is measured by either contact gaging, optical projection, or laser inspection equipment. All other dimensions, such as pitch diameter, lead, thread form, and minor diameter may be inspected by optical projection methods, with a magnification of lOOX recommended. A suggested chart for this method is shown in Appendix A. The thread plug gages and the tap are inspected in a similar manner to externally threaded parts. Contact gaging, such as the use of “GO” and “NOT GO’ ring gages, measuring wires, and set plug gages may be used for sizes 0.70 UNM and above.

1.5.3 Internal Threads. The minor diameter of the intemal thread is gaged with “GO’ and “NOT GO’ plain cylindrical plug gages. All other elements are checked only for assemble-ability limits by means of a “GO’ thread plug gage, taking extreme care not to damage the thread. For the minimum material limits of the internal threads, the accuracy and performance

’ When the American National Standards referred to in this Standard - are superseded by a revision approved by the American National May also be obtained from American National Standards Institute. Standards Institute, the revision shall apply. I I West 42nd Street. New York, NY 10036.

1


ASME B1.10M-1997

of the tap is relied upon. This implies that the major and pitch diameters of the tap do not exceed the maximum internal thread limits for these elements, and disregards over cutting, which is rarely incurred because of the flexibility of these small taps and the manner in which they are generally fluted.

It is recommended that the minor diameter of the internal thread be gaged with one insertion of the “NOT GO” plain cylindrical plug gage first. The “NOT GO’ plain cylindrical plug gage shall be inserted only until it meets some resistance. The minor diameter is then gaged with only one insertion of the plain cylindrical plug gage per thread, as the act of gaging can wear the thread oversize. At this point, the minor diameter is considered to be acceptable. The thread is gaged with only one insertion of the “GO’ thread plug gage. The thread is accepted or rejected on the basis of this one insertion. Repeat insertions can wear oddamage the thread.

1.5.4 Reference Temperature. The reference temperature is 20°C for the dimensions defined by this system.

1.5.5 Units of Measure. All dimensions in this Standard, including all tables, are in millimeters unless otherwise specified. Inch conversions may be found in Appendices B, C , and D.

1.5.6 Federal Government Use. When this Stan- dard is approved by the Department of Defense (DOD) and federal agencies, and is incorporated into FED-STD- H2815, Screw-Thread Standards for Federal Services, Section 5 , the use of this Standard by federal government will be subject to all requirements and limitations of FED-STD-H28/5.

2 SCREW THREAD PROFILE

2.1 Scope

The basic profile and design profiles defined in this Section are the basis of all thread dimensions given in this Standard.

2.2 Basic Profile

The basic profile for the UNM screw threads is shown in Fig. 1 (profile applies to the axial plane), and except for one element is the Unified Basic Thread Form. The exception is the height of thread engagement for which the basic value is 0.5548. The basic thread height of 0.5548 (0.48P) will not affect interchangeabil-


ity with products made to the 1958 revision of this Standard showing 0.52P. As the resulting difference is negligible and completely offset by practical considerations in tapping, full internal thread heights are avoided in these small sizes to escape excessive tap breakage.

For reference, the basic profile for UNM screw threads is identical to that for IS0 metric threads in ISO/R1501.

2.3 Design Profiles

The design profiles define the maximum material conditions for the external and internal unified miniature thread as shown in Fig. 2. These forms are derived from the basic profile shown in Fig. I by the application of clearances for the crests of the addendum at the roots of the mating dedendum forms, and thereby satisfy the practical consideration that the contact between the mating pair be limited to functional surfaces of the fasteners.

2.3.1 Practically speaking, product made to the requirements of this Standard will be interchangeable with product made to any other standards allowing a maximum depth of engagement (or combined addendum height) of 0.5548. Internal thread heights exceeding 0.5548 should be avoided in the small thread sizes in order to avoid excessive tap breakage.

2.3.2 Formulas for the various dimensions are given in both Fig. 2 and Table 1. Values of the various dimensions for all pitches are given in Table 2.

2.4 Lead

All threads are of the single (single start) type.

2.5 Nominal Size

The thread sizes comprising this series and their respective pitches are shown in the third and second columns, respectively, of Table 4. Formulas for the dimensions are listed in Table 3. Corresponding values for all sizes are given in Table 4.

2.6 Classifications

This Standard establishes only one class of thread, with zero allowance on all diameters, in view of the manufacturing difficulties which any differentiations in tolerance would impose and because there is no demonstrated need for additional classes.


UNIFIED MINIATURE SCREW THREADS ASME B1.10M-1997

0.10825318P (0.125.H)

Pitch line "."_ 0.86602540P

Axis of screw thread

GENERAL NOTE: For standardization, this Table of thread values has been established based on a function of pitch, P. The thread values based on a functional height, H, are used as reference only.

FIG. 1 BASIC PROFILE FOR THE UNM SCREW THREADS

2.7 Tolerance

2.7.1 All tolerance governing limits of size are based on functions of the pitch only and apply to lengths of engagement from v3 to 1 v2 times the nominal diameter. Lengths of engagement and nominal diameter are not incorporated in any of the tolerance formulas in view of the following.

(u) In the small thread sizes covered by this Standard, lengths of engagement significantly below or above the range covered by the formulas are not frequently employed.

(b ) Functional fitness in these small sizes is depen- dent principally upon the properties of the thread rather than the size of the threaded number.

(c) Total tolerance is too small to permit the imposi- tion of minor modifications.

2.7.2 On external threads, tolerance is applied to the design sizes in the minus direction. On internal threads, tolerance is applied to the design size in the plus direction. Tolerance formulas are given in Table 5. Their values are given in Table 6.

2.8 Coated Threads

It is not within the scope of this Standard to make recommendations for thickness of, or specify limits for, coatings.

2.9 Limits of Size

The limits of size resulting from the application of the specified tolerance are illustrated in Fig. 3. Their values are given in Table 6.

3


ASME B1.10M-1997 UNIFIED MINIATURE SCREW THREADS

Basis for minimum major 0.07216878P diameter specified in

90 deg 4 Axis of internal thread

"" ---

A I \

"I-

I 'Junction of root Basis for maximum minor contour and flank diameter specified in

90 deg Tables

/ --..- Axis of external thread

GENERAL NOTE: For standardization, this Table of thread values has been established based on a function of pitch, f . The thread values based on a functional height, H, are used as reference only.

FIG. 2 DESIGN (MAXIMUM MATERIAL) THREAD FORMS

4



TABLE 1 THREAD FORM FORMULAS

Element Symbol Formula

BASIC THREAD FORM

Angle of thread 2oL Half angle of thread Pitch of thread P Height of sharp V thread H Addendum of basic thread Height of basic thread

oL

hab hb

DESIGN FORM - EXTERNAL THREAD

Addendum has Height h, Flat at crest F C S

Radius at root r,

DESIGN FORM - INTERNAL THREAD

Height of engagement Height of thread Flat at crest Radius at root

he hn Fcn r ,

60 deg 30 deg

0.86602540P 0.32475953P (0.375H) 0.48000000P (0.554M

0.32475953P (0.375H) 0.57259074P (0.661 H) O. 12500000 P 0.18518149P

0.48000000P (0.554M 0.48000000P (0.554M 0.32074374P 0.07216878P ...

GENERAL NOTE: For standardization, this Table of thread values has been established based on a function of pitch, P. The thread values based on a functional height, H, are used as reference only.

5


TABL

E 2

THR

EAD

FO

RM

D

IMEN

SIO

NS,

’ BA

SIC

AN

D

DES

IGN

Pitch

P

Heigh

t of

Shar

p V,

H=

0.8

6602

54OP

Heigh

t of

Inter

nal

Thre

ad

and

Depth

of

Thre

ad

Enga

geme

nt,

0.554

H =

0.46

0000

00P

Dede

ndum

of

Inter

nal

Thre

ad

and

Adde

ndum

of

Exter

nal

Thre

ad,

0.375

H =

0.32

4759

53P

Heigh

t, 0.

661

H =

0.57

2590

74P

Flat

at Cr

est,

Fcs

= 0.1

25OO

OOOP

Radiu

s at

Root,

rrs

=

0.18

5181

49P

Roun

ded

Root

Heigh

t, 0.5

96H

= 0.

5160

8439

P

Flat

at Cr

est,

Fen

= 0.

3207

4374

P

m 0.

080

0.06

928

0.03

840

0.02

598

0.04

581

0.01

00

0.09

0 0.

0779

4 0.

0432

0 0.

0292

3 0.

0515

3 0.

0113

0.

100

0.08

660

0.04

800

0.03

248

0.05

726

0.01

25

0.12

5 0.

1082

5 0.

0600

0 0.

0405

9 0.

0715

7 0.

0156

0.

150

0.12

990

0.07

200

0.04

871

0.08

589

0.01

88

0.01

5 0.

017

0.01

9 /

0.02

3 0.

028

0.04

129

0.02

57

0.00

6 0.

0464

5 0.

0289

0.

006

0.05

161

0.03

2 1

0.00

7 0.

0645

1 0.

0401

0.

009

0.07

741

0.04

81

0.01

1

0.17

5 0.

1515

5 0.

0840

0 0.

0568

3 0.

1002

0 0.

0219

0.

032

0.09

031

0.05

61

0.20

0 0.

1732

1 0.

0960

0 0.

0649

5 0.

1145

2 0.

0250

0.

037

0.10

322

0.06

41

0.22

5 0.

1948

6 0.

1080

0 0.

0730

7 0.

1286

3 0.

0281

0.

042

0.11

612

0.07

22

0.25

0 0.

2165

1 0.

1200

0 0.

0811

9 0.

1431

6 0.

0313

0.

046

0.12

902

0.08

02

0.30

0 0.

2598

1 0.

1440

0 0.

0974

3 0.

1717

8 0.

0375

0.

056

0.15

483

0.09

62

Basic

Th

read

Fo

rm

r Di

mens

ions,

mm

Exter

nal

Thre

ad

Desig

n Fo

rm

r

GENE

RAL

NOTE

: Fo

r sta

ndar

dizati

on,th

is Ta

ble

of thr

ead

value

s ha

s be

en

estab

lishe

d ba

sed

on

a fun

ction

of

pitch

, I?

The

threa

d va

lues

base

d on

a

functi

onal

heigh

t, /i,

are

used

as

re

feren

ce

only.

NOTE

: (I)

For

inch

conv

ersio

n of

Table

2,

see

Appe

ndix

B.

Radiu

s at

Root,

r,,

= 0.

0721

6878

P

Inter

nal

Thre

ad

Desig

n Fo

rm

0.01

3 0.

014

0.01

6 0.

018

0.02

2 2 -n m 0



TABLE 3 THREAD SIZE FORMULAS, BASIC AND DESIGN

Dimension Symbol Formula [Note (111

Major diameter, nominal and basic D, d (BSC) Major diameter of external thread d D, d (BSC) Major diameter of internal thread D D, d (BSC)

. . .

Pitch diameter, basic 44 (BSC) D,d (BSC)-Zh,b =

Pitch diameter of external thread 4 44 (BSC)

Pitch diameter of internal thread 4 44 (BSC)

D,d (BSC)-0.64951905P

[Note (2)l

Minor diameter, basic Old1 (BSC) D,d (BSC)-Zhb =

Minor diameter of external thread 4 D,d (BSC)-2hs =

Minor diameter of internal thread 4 014 (BSC)

NOTES: (1) Metric units (millimeters) apply in all formulas. (2) Only one class of thread, with no allowance on the pitch diameter, is provided.

D,d (BSC)-O.96P

D,d (BSC)-l.l4518P

7


TABL

E 4

THR

EAD

SI

ZE D

IMEN

SIO

NS,

’ BA

SIC

AN

D

DES

IGN

Size

De

signa

tion

Pitch

, P

Basic

Ma

jor

Basic

Pi

tch

Mino

r Di

amete

r Di

amete

r, Di

amete

r, Ex

terna

l Th

read

s, W

4X4

d,-l.

l4518

P=

4

Mino

r Di

amete

r Int

erna

l Th

read

s, D,

-0.96

P

Nomi

nal

Major

Di

amete

r Int

erna

l Th

read

s, D

mm

mm

mm

mm

mm

0.30

UNM

0.08

0 0.

300

0.24

8 0.

208

0.22

3 0.

300

0.35

UNM

0.09

0 0.

350

0.29

2 0.

247

0.26

4 0.

350

0.40

m 0.4

5 0.5

0 0.5

5

UNM

0.10

0 0.

400

0.33

5 0.

285

0.30

4 0.

400

UNM

0.10

0 0.

450

0.38

5 0.

335

0.35

4 0.

450

UNM

0.12

5 0.

500

0.41

9 0.

357

0.38

0 0.

500

UNM

0.12

5 0.

550

0.46

9 0.

407

0.43

0 0.

550

0.60

UNM

0.15

0 0.

600

0.50

3 0.

428

0.45

6 0.

600

0.70

UNM

0.17

5 0.

700

0.58

6 0.

500

0.53

2 0.

700

0.80

UNM

0.20

0 0.

800

0.67

0 0.

571

0.60

8 0.

800

0.90

UNM

0.22

5 0.

900

0.75

4 0.

642

0.68

4 0.

900

1.00

UNM

0.25

0 1 .

ooo

0.83

8 0.

714

0.76

0 1.

000

1.10

UNM

0.25

0 1.

100

0.93

8 0.

814

0.86

0 1.

100

1.20

UNM

0.25

0 1.

200

1.03

8 6.

914

0.96

0 1.

200

1.40

UNM

0.30

0 1.

400

1.20

5 1.

056

1.11

2 1.

400

Lead

An

gle

at Se

ction

al Ar

ea

Basic

Pi

tch

at Mi

nor

Diam

eter,

Diam

eter

4, h

D-1.1

44P

deg

min

5 52

5

37

5 26

4

44

5 26

4

51

5 26

5

26

5 26

5

26

5 26

4

51

4 23

4

32

sq

mm

0.03

398

0.04

792

0.06

379

0.08

814

0.10

010

0.13

010

0.14

387

0.19

635

0.25

607

0.32

371

0.40

039

0.52

040

C z 0.

6561

2 5

0.87

583

ii 0

GENE

RAL

NOTE

: Si

zes

show

n in

bold

type

are

prefe

rred.

It is

reco

mmen

ded

that

selec

tion

be

confi

ned

to the

se

sizes

ins

ofar

as

poss

ible.

-NOT

E:

(1)

For

inch

conv

ersio

n of

Table

4,

See

Appe

ndix

C.



TABLE 5 TOLERANCE FORMULAS FOR LIMITS OF SIZE

Dimension Formula ~ ~~

External thread, major diameter 0.12P + 0.006 External thread, pitch diameter 0.08P + 0.008 External thread, minor diameter

[Note (111 O. 16P + 0.008

Internal thread, major diameter

Internal thread, pitch diameter 0.08P + 0.008 Internal thread, minor diameter 0.32P + 0.012

[Note (111 0.168P + 0.008

ASME Bl.lOM-1997

NOTE: (1) Tolerance is used in the design of tools.

9


W

i P G 5

TABL

E 6

LIM

ITS

OF

SIZE

AN

D

TOLE

RAN

CES

r Ex

terna

l Th

read

s

Pitch

Di

amete

r

Inter

nal

Thre

ads

Mino

r Di

amete

r r

Pitch

Di

amete

r r Ma

jor

Diam

eter

t I-

r Mino

r Di

amete

r

Min.

, Ma

x. (1)

. mm

0.30

0 0.

321

0.35

0 0.

373

0.40

0 0.

425

0.45

0 0.

475

0.50

0 0.

529

0.55

0 0.

579

0.60

0 0.

633

0.70

0 0.

737

0.80

0 0.

842

0.90

0 0.

946

1 .oo

o 1.

100

1.20

0 1.

400

1.05

0 1.

150

1.25

0 1.

458

5 5 iF 0

Major

Di

amete

r

Size

De

signa

tion

Min.

, mm

To

l., mm

Mi

n.,

mm

Min.

, mm

0.30

UNM

0.35

UNM

0.40

UNM

0.45

UNM

0.50

UNM

s 0.5

5 UN

M

0.60

UNM

0.70

UNM

0.80

UNM

0.90

UNM

1 .OO

UNM

1.1

0 UN

M 1.2

0 UN

M 1.4

0 UN

M

0.28

4 0.

333

0.01

4 0.

015

0.22

3 0.

264

0.24

8 0.

292

0.38

2 0.

432

0.47

9 0.

529

0.01

6 0.

016

0.01

8 0.

018

0.30

4 0.

354

0.38

0 0.

430

0.33

5 0.

385

0.41

9 0.

469

Pitch

, Ma

x.,

Tol.,

Max.,

Mi

n.,

Max.,

Mi

n.

II),

Max.,

To

l., mm

mm

mm

mm

mm

mm

mm

mm

mm

0.08

0 0.

300

0.01

6 0.

248

0.23

4 0.

208

0.18

7 0.

266

0.03

7 0.

090

0.35

0 0.

017

0.29

2 0.

277

0.24

7 0.

225

0.30

5 0.

041

0.10

0 0.

400

0.01

8 0.

335

0.31

9 0.

285

0.26

1 0.

348

0.04

4 0.

100

0.45

0 0.

018

0.38

5 0.

369

0.33

5 0.

311

0.39

8 0.

044

0.12

5 0.

500

0.02

1 0.

419

0.40

1 0.

357

0.32

9 0.

432

0.05

2 0.

125

0.55

0 0.

021

0.46

9 0.

451

0.40

7 0.

379

0.48

2 0.

052

0.15

0 0.

600

0.02

4 0.

503

0.48

3 0.

428

0.39

6 0.

516

0.06

0 0.

175

0.70

0 0.

027

0.58

6 0.

564

0.50

0 0.

464

0.60

0 0.

068

0.20

0 0.

800

0.03

0 0.

670

0.64

6 0.

571

0.53

1 0.

684

0.07

6 0.

225

0.90

0 0.

033

0.75

4 0.

728

0.64

2 0.

598

0.76

8 0.

084

0.25

0 1.

000

0.03

6 0.

838

0.81

0 0.

714

0.66

6 0.

852

0.09

2 0.

250

1.10

0 0.

036

0.93

8 0.

910

0.81

4 0.

766

0.95

2 0.

092

0.25

0 1.

200

0.03

6 1.

038

1.01

0 0.

914

0.86

6 1.

052

0.09

2 0.

300

1.40

0 0.

042

1.20

5 1.

173

I .05

6 1 .

ooo

1.22

0 0.

108

GENE

RAL

NOTE

S:

(a)

For

inch

conv

ersio

n of

Table

6,

see

Appe

ndix

D.

(b)

Size

s sh

own

in bo

ld typ

e ar

e pr

eferre

d. It

is re

comm

ende

d tha

t se

lectio

n be

co

nfine

d to

these

siz

es

insofa

r as

po

ssibl

e.

0.57

6 0.

673

0.77

0 0.

867

0.02

0 0.

022

0.02

4 0.

026

0.45

6 0.

532

0.60

8 0.

684

0.50

3 0.

586

0.67

0 0.

754

0.96

4 1.

064

1.16

4 1.

358

0.02

8 0.

028

0.02

8 0.

032

0.76

0 0.

860

0.96

0 1.

112

0.83

8 0.

938

1.03

8 1.

205

NOTE

: (1)

Di

mens

ion

is us

ed

in the

de

sign

of too

ls.

Gene

rally

, dia

meter

ac

cepta

nce

is ba

sed

upon

ma

ximum

ma

teria

l co

nditio

n ga

ging,

Max.,

mm

To

l., mm

0.26

2 0.

307

0.01

4 0.

015

0.35

1 0.

016

0.40

1 0.

016

0.43

7 0.

018

0.48

7 0.

018

0.52

3 0.

020

0.60

8 0.

022

0.69

4 0.

024

0.78

0 0.

026

0.86

6 0.

028

0.96

6 0.

028

1.06

6 0.

028

1.23

7 0.

032

I 0 -d

ln -0

o-



'I2 tolerance on major diameter r of external thread

L

c al al

.- 5 U

.- ô E m

u v] .- m

U m

5

E

L

- m al

al

O

al al

c

L

L

c

.- 5

i 5

I

U O L

.-

E .- X

U

r, 2

E - m al X al

O

al al

c

L

L

c

5

E 5

.- U

.- ô

._ E

r c .-

External Thread [Screw)

' /2 minor diameter tolerance on external thread

U m

r, ?

E - m al X al

O

al

Y

c

L

c

E m U

O c

.- L

.- E

E 6

r" .- Y

U , m ? 5 - m al C

E c .- c O L

CI al al

.- E, U L

O C .- E E .- X

2

FIG. 3 DISPOSITION OF TOLERANCES AND CREST CLEARANCES

I I


APPENDIX A GAGES AND GAGING FOR UNIFIED MINIATURE SCREW THREADS

(This Appendix is not part of ASME B1.10M-1997 and is included for information only.)

The establishment of specifications for gages for Unified Miniature Screw Threads is not within the scope of this document. However, in the absence of a gage standard, the development of which is awaiting the accumulation of more experience with this thread standard, there is presented below, i n Fig. A l , an illustration of a chart which has been found very satisfactory for the optical projection method of inspection of external threads. Inspection at a magnification of lOOX is recommended and at this scale the charts should be accurate to within +0.01 in. on all diameters and on pitches cumulatively up to five pitches.

13


Maximum envelope Limits

Minimum major

Minimum Pitch - - Minimum minor

0.80 UNM External Thread

1 oox

Minor diameter

Pitch diameter

Major diameter . I Set-up

FIG. A l EXAMPLE OF PROJECTION COMPARATOR CHART FOR EXTERNAL THREAD

14


APPENDIX B INCH CONVERSION OF TABLE 2

(This Appendix is not part of ASME Bl.lOM-1997 and is included for information only.)


TABL

E B

l TH

REA

D

FOR

M

DIM

ENSI

ON

S,

BASI

C

AND

D

ESIG

N

Thre

ads

Per

Inch, n

z 31

7 '/2

0.

0031

50

0.00

2728

0.

0015

12

0.00

1023

0.

0018

04

0.00

039

2827

9 0.

0035

43

0.00

3069

0.

0017

01

0.00

1151

0.

0020

29

0.00

044

254

0.00

3937

0.

0034

09

0.00

1890

0.

0012

78

0.00

2254

0.

0004

9 20

3 ?I

0.00

492

1 0.

0042

62

0.00

2362

0.

0015

98

0.00

2818

0.

0006

1 16

9 5;

0.00

5906

0.

0051

14

0.00

2835

0.

0019

18

0.00

3381

0.

0007

4

0.00

06

0.00

1626

0.

0010

1 0.

0002

0.

0007

0.

0018

29

0.00

114

0.00

02

0.00

07

0.00

2032

0.

0012

6 0.

0003

0.

0009

0.

0025

40

0.00

158

0.00

04

0.00

11

0.00

3048

0.

0018

9 0.

0004

145

7, 0.

0068

90

0.00

5967

0.

0033

07

0.00

2237

0.

0039

45

0.00

086

0.00

13

0.00

3556

0.

0022

1 0.

0005

12

7 0.

0078

74

0.00

6819

0.

0037

80

0.00

2557

0.

0045

09

0.00

098

0.00

15

0.00

4064

0.

0025

2 0.

0006

11

28/,

0.00

8858

0.

0076

72

0.00

4252

0.

0028

77

0.00

5072

0.

0011

1 0.

0017

0.

0045

72

0.00

284

0.00

06

101

"/5

0.00

9843

0.

0085

24

0.00

4724

0.

0031

96

0.00

5636

0.

0012

3 0.

0018

0.

0050

80

0.00

316

0.00

07

84

T3

0.01

1811

0.

0102

29

0.00

5669

0.

0038

36

0.00

6763

0.

0014

8 0.

0022

0.

0060

96

0.00

379

0.00

09

Pitch

, P

Basic

Th

read

Fo

rm

Heigh

t of

Shar

p V,

H=

0.8

6602

54OP

Heigh

t of

inter

nal

Thre

ad

and

Depth

of

Thre

ad

Enga

geme

nt,

0.554

H =

0.48O

OOOO

OP

-r

Dede

ndum

of

Inter

nal

Thre

ad

and

Adde

ndum

of

Exter

nal

Thre

ad,

0.37

5 H

= 0.

3247

5953

P

Exter

n

Heigh

t, 0.6

61H

= 0.

5725

9074

P

Thre

ad

Desic

Fo

rm

Flat

at Cr

est,

Fcs

= 0.

1250

0000

P

Radiu

s at

Root,

rrs

=

0.18

5181

49P

Inter

n

Boun

ded

Root

Heigh

t, 0.

596

H =

0.51

8084

39P

GENE

RAL

NOTE

: Fo

r sta

ndar

dizati

on,

this

Table

of

threa

d va

lues

has

been

es

tablis

hed

base

d on

a

functi

on

of pit

ch,

P. T

he

threa

d va

lues

base

d on

a

functi

onal

heigh

t, H,

ar

e us

ed

as

refer

ence

on

ly.

Thre

ad

Desig

Fo

rm

Flat

at Ra

dius

at Cr

est,

Root,

Fe

n =

r m =

0.

3207

4374

P 0.

0721

6878

P


APPENDIX C INCH CONVERSION OF TABLE 4

(This Appendix is not part of ASME B1.10M-I997 and is included for information only.)

17


VI

-I W . z

Size

De

signa

tion

Nomi

nal

Major

Di

amete

r Int

erna

l Th

read

s, D

in.

0.30

UNM

0.35

UNM

0.01

18

0.01

38

z 0.4

0 UN

M 0.4

5 UN

M 0.5

0 UN

M 0.5

5 UN

M

Mino

r Di

amete

r Ba

sic

Major

Ba

sic

Pitch

Mi

nor

Diam

eter

Inter

nal

Diam

eter,

0, Di

amete

r, Ex

terna

l Th

read

s, Th

read

s, d

Thre

ads

4.4

d,-1.1

4518

k 4

D,-0

.96P

Per

Inch,

n in.

in.

in.

in.

318

0.01

18

0.06

68

0.00

82

0.00

88

282

0.01

38

0.01

15

0.00

97

0.01

04

254

0.01

57

0.01

32

0.01

12

0.01

20

254

0.01

77

0.01

52

0.01

32

0.01

39

203

0.01

97

0.01

65

0.01

41

0.01

50

203

0.02

17

0.01

85

0.01

60

0.01

69

169

0.02

36

0.01

98

0.01

69

0.01

80

145

0.02

76

0.02

31

0.01

97

0.02

09

127

0.03

15

0.02

64

0.02

25

0.02

39

*13

0.03

54

0.02

97

0.02

53

0.02

69

102

0.03

94

0.03

30

0.02

81

0.02

99

102

0.04

33

0.03

69

0.03

20

0.03

39

102

0.04

72

0.04

09

0.03

60

0.03

78

85

0.05

51

0.04

74

0.04

16

0.04

38

GENE

RAL

NOTE

: Si

zes

show

n in

bold

type

are

prefe

rred.

It is

reco

mmen

ded

that

selec

tion

be

confi

ned

to the

se

sizes

ins

ofar

as

poss

ible.

0.01

57

0.01

77

0.01

97

0.02

17

0.60

UNM

0.70

UNM

0.80

UNM

0.90

UNM

0.02

36

0.02

76

0.03

15

0.03

54

1 .oo

UN

M 1.1

0 UN

M 1.2

0 UN

M 1.4

0 UN

M

0.03

94

0.04

33

0.04

72

0.05

51

TABL

E C

l TH

REA

D

SIZE

D

IMEN

SIO

NS,

BA

SIC

AN

D

DES

IGN

Lead

An

gle

at Ba

sic

Pitch

Di

amete

r, A

deg

min

5 52

5

37

5 26

4

44

5 26

4

51

5 28

5

26

5 26

5

26

5 26

4

51

4 23

4

32

Secti

onal

Area

at

Mino

r Di

amete

r 4,

D-1.1

4518

P

sq

in.

5.27

x 1O

-5 7.4

3

9.88

1.37

x 10

-4

1.55

2.02

2.23

3.04

3.97

5.02

6.21

8.07

1.02

x 10

-3

1.36


APPENDIX D INCH CONVERSION OF TABLE 6

(This Appendix is not part of 6l.lOM-1997 and is included for information only.)


TABL

E D

l LI

M-IT

S O

F SI

ZE A

ND

TO

LER

ANC

ES

f

Exter

nal

Thre

ads

Pitch

Di

amete

r

Inter

nal

Thre

ads

Mino

r Di

amete

r T

Pitch

Di

amete

r T

Major

Di

amete

r T

Major

Di

amete

r Mi

nor

Diam

eter

Size

De

signa

tion

Thre

ads

Per

Inch

Max.,

Mi

n.,

Tol.,

Max.,

Mi

n.,

Tol.,

Max.,

Mi

n.

(I),

Min.

, Ma

x.,

Tol.,

Min.

, Ma

x.,

Tol.,

in.

in.

in.

in.

in.

in.

in.

in.

in.

in.

in.

in.

in.

in.

L Min.

, in.

Ma

x. (1

1, in.

0.30

UNM

0.35

UNM

318

0.01

18

0.01

12

0.00

06

0.00

98

0.00

92

0.00

06

0.00

62

0.00

74

0.00

88

0.01

02

0.00

14

282

0.01

38

0.01

31

0.00

07

0.01

15

0.01

09

0.00

06

0.00

97

0.00

89

0.01

04

0.01

20

0.00

16

0.00

98

0.01

04

0.00

06

0.01

18

0.01

26

0.01

15

0.01

21

0.00

06

0.01

38

0.01

47

0.40

UNM

254

0.01

57

0.01

50

0.00

07

0.01

32

0.01

26

0.00

06

0.01

12

0.01

03

0.01

24

0.01

37

0.00

17

0.01

32

0.01

38

0.00

06

0.01

57

0.01

67

0.45

UNM

254

0.01

77

0.01

70

0.00

07

0.01

52

0.01

45

0.00

07

0.01

32

0.01

22

0.01

39

0.01

57

0.00

18

0.01

52

0.01

58

0.00

06

0.01

77

0.01

87

0.50

UNM

203

0.01

97

0.01

89

0.00

08

0.01

65

0.01

58

0.06

67

0.01

41

0.01

30

0.01

50

0.01

70

0.00

20

0.01

65

0.01

72

0.00

07

0.01

97

0.02

08

g 0.5

5 UN

M 20

3 0.

0217

0.

0208

0.

0009

0.

0185

0.

0177

0.

0008

0.

0160

0.

0149

0.

0169

0.

0190

0.

0021

0.

0185

0.

0192

0.

0007

0.

0217

0.

0228

0.60

UNM

169

0.02

36

0.02

27

0.00

09

0.01

98

0.01

90

0.00

08

0.01

69

0.01

56

0.01

80

0.02

03

0.00

23

0.01

98

0.02

06

0.00

08

0.02

36

0.02

49

0.70

UNM

145

0.02

76

0.02

65

0.00

11

0.02

31

0.02

22

0.00

09

0.01

97

0.01

83

0.02

09

0.02

36

0.00

27

0.02

31

0.02

40

0.00

09

0.02

76

0.02

90

0.80

UNM

127

0.03

15

0.03

03

0.00

12

0.02

64

0.02

54

0.00

10

0.02

25

0.02

09

0.02

39

0.02

89

0.00

30

0.02

64

0.02

73

0.00

09

0.03

15

0.03

31

0.90

UNM

113

0.03

54

0.03

41

0.00

13

0.02

97

0.02

87

0.00

10

0.02

58

0.02

35

0.02

69

0.03

02

0.00

33

0.02

97

0.03

07

0.00

10

0.03

54

0.03

72

1.00

UNM

102

0.03

64

0.03

80

0.00

14

0.03

30

0.03

19

0.00

11

0.02

81

0.02

62

0.02

99

0.03

35

0.06

36

0.03

30

0.03

41

0.00

11

0.03

94

0.04

13

1.10

UNM

102

0.04

33

0.04

19

0.00

14

0.03

67

0.03

58

0.00

11

0.03

20

0.03

02

0.03

39

0.03

75

0.00

36

0.03

67

0.03

80

0.00

11

0.04

33

0.04

53

1.20

UNM

102

0.04

72

0.04

58

0.00

14

0.04

09

0.03

97

0.00

12

0.03

60

0.03

41

0.03

78

0.04

14

0.00

36

0.04

09

0.04

26

0.00

11

0.04

72

0.04

92

1.40

UNM

85

0.05

51

0.05

35

0.00

16

0.04

74

0.04

62

0.00

12

0.04

16

0.03

94

0.04

38

0.04

80

0.00

42

0.04

74

0.04

87

0.00

13

0.05

51

0.05

74

GENE

RAL

NOTE

: Si

zes

show

n in

bold

type

are

prefe

rred.

It is

reco

mmen

ded

that

selec

tion

be

confi

ned

to the

se

sizes

ins

ofar

as

poss

ible.

NOTE

: (1)

Di

mens

ion

is us

ed

in the

de

sign

of too

ls.

Gene

rally

dia

meter

ac

cepta

nce

is ba

sed

upon

ma

ximum

ma

teria

l co

nditio

n ga

ging.
