ASME B1.10M

Errata to ASME B1.10M-1997 Unified Miniature Screw Threads Onpage 6, in Table 2, underthefifthcolumnheading Height, 0.661H = 0.57259074P, the eighth and ninth entries were corrected to readO. 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

I 111 111 II IlIl Il N2597E

COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services


0.08928 0.07794 0.08660 0.10825 0.12990

0.15155 0.17321 0.19496 0.21851 0.25981

0.080 0.090 0.100 0.125 0.150

0.175 0.209 0.225 0.250 0.300

NOTE: (1) For inch

conversion

of Table

2,seeAppendix

height,

0.08400 0.09600 0.10800 0.12000 0.14400

0.03840 0.04320 0.04600 0.06000 0.07200

6.564H = 0.48oO6wOP

GENERAL NOTE: For standsrdization,this thread values based on a functional

0.66602540P

P

Pitch

Height of ShwP v. H=

Height of Internal Thread and Depth of Thread Entmmmt

BaskThreadForm

of thread

6.

H, are used

Table

0.05683 0.06495 0.07307 0.08119 0.09743

0.02598 0.02923 0.03248 0.04059 0.04871

values as reference

6.375H = 032475953P

Dedendum of Intern81 Thread and Addendum of External Thrwd.

based

has been only.

0.0219 0.0250 0.0281 0.0313 0.0375

0.0100 0.0113 0.0125 0.0156 0.0188 0.032 0.037 0.042 0.046 0.056

0.015 0.017 0.019 0.023 0.028

of pitch,

Radius at Root, r, = 0.18518149P

on a function

Flat at Crest, F, = 0.125OOOOOP

0.10020 0.11452 0.12883 0.14315 0.17178

0.04581 0.05153 0.05728 0.07157 0.08589

established

Height, 0.661 H = 057259074P

mm

External Thread Design Form

Dimensions.

TABLE 2 THREAD FORM DIMENSIONS,’ BASIC AND DESIGN Internal

=

0.09031 0.10322 0.11612 0.12902 0.15483

0.04129 0.04645 0.05161 0.06451 0.07741

0.5150843gP

0.566H

Rounded Root Height,

/? The

l-

0.0561 0.0641 0.0722 0.0802 0.0962

0.0257 0.0289 0.0321 0.0401 0.0481

F, = 0.33674374P

Flat at Crest,

0.013 0.014 0.016 0.018 0.022

0.006 0.006 0.007 0.009 0.011

Radius at Root r, = 0.07216678P

Thread Design Form


A NA M E R I C A NN A T I O N A LS T A N D A R D

ASME B1.l OM-1887 (Revision of ASA B1.lO-1958) COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services

~

S T D - A S M E B L - L O M - E N G L L797 I0 7 5 7 b 7 0 0 5 8 3 0 3 0 2 2 b 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 toparticipate. The proposed codeor standard was made availablefor 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 thisdocument, and does not undertake to insure anyone utilizing astandard againstliability for infringement of any applicable LettersPatent, nor assume any such liability. Users of a code or standard are expressly advised that the determination of the validity of anysuch patent rights, and the risk of the infringement ofsuch 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, i n an electronic retrieval system or otherwise, without the prior written permission of thepublisher.

The American Society of Mechanical Engineers 345East 47th Street, New York,NY10017

Copyright Q 1997 by THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS All Rights Reserved Printed i n 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 beenunder study since 1927, when theNational Screw Thread commission prepared a compilation of the practices of American manufacturers and various foreign standards. The latter includedthe Swiss standard NHS 56100, whichfirst appeared in 1923. However, for in theUnited States until1943, want of sufficient interest, no further actionwastaken 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 threadmatters confined principally to the instrument industry, the American Standards Association established, in 1944, ASAWar Committee B1.7on Instrument Screw Threads. The first significant progress toward standardization andunification 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 mmto 0.90 mm having a 50 degthread angle, andthe development of a series closely following the NHS series for sizes larger than 0.90 mm with a 60 deg threadangle. In June 1946 the War Committee was converted to Subcommittee No. 4 on Instrument Screw Threads of ASME Sectional Committee B1, Shortly thereafter it waslearnedthat Swiss manufacturers werenot adhering entirely to NHS 56100, butthatthe 60 deg thread angle made essentially in accordance withtheUnified Thread Form wasbeingwidely used for the sizes below 1 mm.From this information andtheresults of subsequent experimental work by watchand instrument manufacturers bothhereandabroad,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 therange from 0.25 mm to 1.40 mm was adopted for recommendation to allnational standardizing bodies. The Committee also agreedthat further studies should bemaderegardingtheuse of the IS0 BasicProfile (or Unified Thread Form) in this range. In theUnited States, where subsequent studies revealed noneed, either current or anticipated, for sizes below 0.30 mm,itwas established that the 60 deg angle for all sizes was feasible. It was also determined thattheminor diameter of internal threads must be, andinvariablyis,kept above the minimumvalue established by the Unified Thread Form toavoid excessive tapping difficulties. From this conclusion andthe calculation problems presented by theneed for dimensioning this Standard in bothmetric and inch units, a simple plan evolved basedonthe coefficient of 0.52 in place of 0.54127 for basicthread 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) thatthe 60 deg thread angle be adopted over the entire range; ( c ) that the design thread forms bebasedonthesimplifiedvalue of 0.52P, instead of 0.54127P, for thebasicthread height.

... 111


The Americanviewswerepresented

atboththe

American-British-Canadian Conference

in April1955andtheplenary session of IS0 in June1955. The latter session developed Draft I S 0 recommendation No. 84 covering a metric series from 0.25 mmto 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 wasstrongly in favor of thesimplified coefficients for the thread sizes 1.400 mm andbelow,andthe previous issue of this Standard was formulated to incorporate the original Americanrecommendation 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 commonpractice on internal threads. entirely of national origin, as recommendations Tolerances given in thisStandardwere on thisphase had not yetbeen 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 revisedand submitted tothe Sectional Committee B1 for letter ballot in April1957. In response to comments receivedwiththe letter ballot, the draft was further modifiedat a meetingof Subcommittee No. 4 on March 6, 1958.Followingthe acceptance of these modifications by the Sectional Committee, theproposalwas submitted toand approved by the sponsor organizations andASA.andwas 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 watchesand instrumentation. There still remains, however, an in spacecrafts and aircrafts, as components are active use of miniature screwthreads miniaturized for weight considerations. Attempts weremade to revise the Standard between 1979 and 1983, butunresolved negative votes defeated the proposed revisions. Efforts to revisethe Standard wereundertakenagain in 1989. The current Standard now has a thread height of 0.554H (0.48P), whichis in agreement with FED-STD-H28/5 and ISO/R1501, and which allows for interchangeability with threads producedtothe previous standardASA 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 metricunits.Inch conversions of thesevalueshavebeenplaced in 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

...

111 V

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 DesignProfiles .............................................................. 2.4 Lead . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5 Nominal Size ............................................................... 2.6 Classifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.7 Tolerance ................................................................... 2.8 Coated Threads .............................................................. 2.9 Limits of Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figures 1 BasicProfile for the UNM Screw Threads ........................................ 2 Design(Maximum Material) Thread Forms ........................................ 3 Disposition of Tolerances and Crest Clearances ....................................

2 2 2 2

2 2 2 2 3 3

3 4

II

Tables 1 Thread Form Formulas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 ThreadFormDimensions,Basicand Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Thread Size Formulas,BasicandDesign .......................................... 4 Thread Size Dimensions, BasicandDesign ........................................ 5 Tolerance Formulas for Limits of Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Limits of Size and Tolerances ....................................................

6 7 8 9 10

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 ......................................................

13 15 17 19

vii


5

ASME B1.10M-1997

UNIFIED MINIATURE SCREW THREADS

1 GENERAL

ANSUASME B I .7M,* Nomenclature, and Definitions, Letter Symbols for Screw Threads Publisher: The American Society of Mechanical Engineers, 345 East 47th Street, New York, NY 10017

1.1 Scope This Standard specifies the thread form, series, tolerance, and designation for theUnifiedMiniatureScrew Threads. The series covers a diameter range of 0.30

mm to unifiedthread

extending the series thatbeginat

“Profile

1.6 mm.

Is0 68, Is0 General Purpose Screw Threads 1 ~ 0 / ~ 1 5 0 1ISO , Miniature screw Threads Publisher: International Organization for Standardization, 3 rue de Varembe, 121 1 Geneva 20, Switzerland

and

1.5 Acceptability

1.2 Unified Miniature Screw Thread Standards

1.5.1 Additional recommended methods for determining the acceptability of miniature screw threads will beincluded as further experience withthisthread standard is reported. Untilsuch time, agreements must bereachedbetween purchaser andvendorregarding 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 beingusedwith considerable success by some producers, are suggested.

The fourteen sizes published in thisStandardwere endorsed by the American-British-Canadian conference of April 1955 as thebasis of theunified standard among inch-using countries, andtocorrespond 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 shouldbeconfined to those indicated in bold type in Table 4. For more restrictive conditions, those sizes indicated in regular type in Table 4 maybe used.

1.5.2External Threads. The major diameter of the external thread is measured by either contact gaging, optical projection, or laser inspection equipment. All other dimensions, suchaspitch diameter, lead,thread form, and minor diameter maybe 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, suchastheuse of “GO” and “NOT GO’ ring gages, measuring wires, and set plug gages may beused for sizes 0.70 UNM and above.

1.3 Designation Unified Miniature Thread sizes of this series shall be designated on engineering drawings, in specifications, andontoolsand 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 full limits of minor diameter, as given in Table 6, shall normallybe considered applicable. Where this is notpermissible, the designation shall be supplemented by theminor diameter limits.

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’ threadplug gage, taking extreme care not to damage the thread. For the minimummaterial limits of the internal threads, theaccuracyand performance

1.4 Reference Documents’ The latest issues of the following documents form a part of this Standard tothe extent specified herein.

’ Whenthe

-

American National Standardsreferred to in thisStandard are superseded by a revision approved by the American National Standards Institute, the revision shall apply.

May also be obtained from American National Standards Institute. 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 andpitch diameters ofthe tap do not exceed the maximum internal thread limits for these elements, and disregards over cutting, which is rarely incurred because of theflexibility of these smalltapsandthemanner in whichthey are generally fluted. Itisrecommendedthattheminor 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 meetssomeresistance. The minor diameter isthen gaged withonlyone insertion of theplain cylindrical plug gage per thread, as the act of gaging canwear thethread oversize. At this point, the minor diameter is considered to be acceptable. The threadisgaged 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.Thereference 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 maybefound in Appendices B, C , andD. 1.5.6 Federal Government Use. When this Standard is approved by the Department of Defense (DOD) and federal agencies, and is incorporated into FED-STDH2815, Screw-Thread Standards for Federal Services, Section 5 , the use of thisStandard by federal government will be subject to all requirements and limitations of FED-STD-H28/5.

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 thesesmall sizes to escape excessive tap breakage. For reference, thebasicprofile for UNMscrew threads is identical tothat for IS0 metric threads in ISO/R1501. 2.3 Design Profiles The design profilesdefinethemaximummaterial 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 matingpair be limitedto functional surfaces of the fasteners. 2.3.1 Practically speaking, product madetotherequirements of this Standard willbe interchangeable with product madetoany 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 bothFig. 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 SCREWTHREADPROFILE 2.1 Scope

The basic profile and design profiles defined in this Section are thebasis of allthread dimensions given in this Standard.

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

2.2 Basic Profile The basicprofile 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-


2.6 Classifications

This Standard establishes only one class of thread, with zero allowance on all diameters, in viewofthe manufacturing difficulties whichany differentiations in tolerance would impose and because there isno demonstrated need for additional classes.

ASME B1.10M-1997


0.10825318P (0.125.H)

Pitch line

"_ .

0.86602540P

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

UNM SCREWTHREADS

FIG.1BASICPROFILEFORTHE

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

2.7 Tolerance 2.7.1 All tolerance governing limits of size are based lengths of engagement from to 1 times the nominal diameter. Lengths of engagement andnominal diameter are not incorporated inany of the tolerance formulas in view of the following. (u) In the small thread sizes covered by this Standard, lengths of engagement significantlybelow or above the range covered by the formulas are notfrequently employed. ( b ) Functional fitness in these small sizes is dependent principally upon the properties of the thread rather thanthe size of thethreaded number. (c) Total tolerance is too small to permit the imposition of minor modifications.

on functions of the pitch only and apply to

v3 v2

2.8 CoatedThreads Itisnotwithinthe scope of this Standard tomake recommendations for thickness of, or specify limits for, coatings.

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

3


ASME B1.10M-1997


0.07216878P

Basis for minimum major diameter specified in

4

90 deg

Axis of internal thread

---

" "

A

I \

"I-

I /

'Junction of root contour and flank

90 deg

Basis for maximum minor diameter specified in 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 o n a functional height, H, are used as reference only.

FIG. 2

DESIGN (MAXIMUM MATERIAL) THREAD FORMS

4



ASME B1.10M-1997

TABLE 1 THREAD FORM FORMULAS Symbol

Element

Formula

BASIC THREAD FORM Angle of thread Half angle of thread Pitch of thread sharpof Height V thread Addendum of basic thread Height of basic thread

2oL oL

P H hab

hb

60 deg 30 deg 0.86602540P 0.32475953P (0.375H) 0.48000000P (0.554M

DESIGN FORM - EXTERNAL THREAD

has h,

Addendum Height Flat at crest Radius at root

FCS

r,

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

DESIGN FORM - INTERNAL THREAD Height of engagement Height of thread Flat at crest Radius at root

he hn Fcn

r,...

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 ofpitch, P. The thread values based on a functional height,H, are used as reference only.

5



m

0.06928 0.07794 0.08660 0.10825 0.12990

0.15155 0.17321 0.19486 0.21651 0.25981

Pitch P

0.080 0.090 0.100 0.125 0.150

0.175 0.200 0.225 0.250 0.300

NOTE: (I) For

inch

conversion

Form

of Table

0.05683 0.06495 0.07307 0.08119 0.09743

0.02598 0.02923 0.03248 0.04059 0.04871

Dedendum of Internal Thread and Addendum of External Thread, 0.375H = 0.32475953P

r

B.

Dimensions,

0.10020 0.11452 0.12863 0.14316 0.17178

0.04581 0.05153 0.05726 0.07157 0.08589

established

External

Height, 0.661 H = 0.57259074P

Table of thread values has been /i, are used as reference only.

2, see Appendix

height,

0.08400 0.09600 0.10800 0.12000 0.14400

0.03840 0.04320 0.04800 0.06000 0.07200

Height of Internal Thread and Depth of Thread Engagement, 0.554H = 0.46000000P

Thread

GENERAL NOTE: For standardization,this thread values based on a functional

Height of Sharp V, H= 0.8660254OP

Basic

mm

based

0.0219 0.0250 0.0281 0.0313 0.0375

0.0100 0.0113 0.0125 0.0156 0.0188 /

0.032 0.037 0.042 0.046 0.056

0.015 0.017 0.019 0.023 0.028

of pitch,

Radius at Root, rrs = 0.18518149P

Form

on a function

Design

at Crest, Fcs = 0.125OOOOOP

Flat

Thread

TABLE 2 THREAD FORM DIMENSIONS,’ BASIC AND DESIGN

r

I? The

0.09031 0.10322 0.11612 0.12902 0.15483

0.04129 0.04645 0.05161 0.06451 0.07741

Rounded Root Height, 0.596H = 0.51608439P

Internal

Design

0.0561 0.0641 0.0722 0.0802 0.0962

0.0257 0.0289 0.032 1 0.0401 0.0481

at Crest, Fen = 0.32074374P

Flat

Thread

0.013 0.014 0.016 0.018 0.022

0.006 0.006 0.007 0.009 0.011

Radius at Root, r,, = 0.07216878P

Form

2 -n m 0


ASME B1.10M-1997

TABLE 3 THREAD SIZE FORMULAS, BASIC AND DESIGN Dimension

Symbol

D, d (BSC)

Major diameter, nominal and basic Major diameter of external thread of internal thread diameter Major

d

Formula [Note (111

... D, d (BSC) D, d (BSC)

D

Pitch diameter, basic

44

Pitch diameter of external thread [Note (2)l Pitch diameter of internal thread

4

= D,d (BSC)-0.64951905P 44 (BSC)

4

44 (BSC)

Minor diameter, basic

Old1 (BSC)

Minor diameter of external thread

4

Minor diameter ofthread internal

4

D,d (BSC)-Zhb = D,d (BSC)-O.96P D,d (BSC)-2hs = D,d (BSC)-l.l4518P 014 (BSC)

(BSC)

D,d (BSC)-Zh,b

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

7



m

UNM UNM UNM UNM

UNM UNM UNM UNM

0.60 0.70 0.80 0.90

1.00 1.10 1.20 1.40

-NOTE: (1) For

inch

conversion

Sizes

UNM UNM UNM UNM

0.40 0.45 0.50 0.55

NOTE:

0.080 0.090

UNM UNM

0.30 0.35

GENERAL as possible.

mm

Size Designation

of Table

shown

0.250 0.250 0.250 0.300

0.150 0.175 0.200 0.225

0.100 0.100 0.125 0.125

mm

Pitch, P

4, See

in bold

are

Appendix

type

1 .ooo 1.100 1.200 1.400

0.600 0.700 0.800 0.900

0.400 0.450 0.500 0.550

0.300 0.350

Basic Major Diameter, W

C.

preferred.

that

0.714 0.814 6.914 1.056

0.428 0.500 0.571 0.642

0.285 0.335 0.357 0.407

0.208 0.247

selection

Minor Diameter External Threads, d,-l.l4518P= 4

It is recommended

0.838 0.938 1.038 1.205

0.503 0.586 0.670 0.754

0.335 0.385 0.419 0.469

0.248 0.292

mm

Basic Pitch Diameter, 4X4

be confined

0.760 0.860 0.960 1.112

0.456 0.532 0.608 0.684

0.304 0.354 0.380 0.430

0.223 0.264

mm

Minor Diameter Internal Threads, D,-0.96P

to these

insofar

1.000 1.100 1.200 1.400

0.600 0.700 0.800 0.900

0.400 0.450 0.500 0.550

0.300 0.350

mm

Nominal Major Diameter Internal Threads, D

sizes

TABLE 4 THREAD SIZE DIMENSIONS,’ BASIC AND DESIGN

5 4 4 4

5 5 5 5

5 4 5 4

5 5

deg

26 51 23 32

26 26 26 26

26 44 26 51

52 37

min

Lead Angle at Basic Pitch Diameter, h

0.87583

0.40039 0.52040 0.65612

0.14387 0.19635 0.25607 0.32371

0.06379 0.08814 0.10010 0.13010

0.03398 0.04792

sq mm

Sectional Area at Minor Diameter 4, D-1.144P

z 5 ii 0

C

ASME Bl.lOM-1997


TABLE 5 TOLERANCE FORMULAS FOR LIMITS OF SIZE Dimension ~

Formula ~~

External thread, major diameter External thread, pitch diameter External thread, minor diameter [Note (111 Internal thread, major diameter [Note (111 Internal thread, pitch diameter Internal thread, minor diameter

+ 0.006 0.08P + 0.008 0.12P

O.16P + 0.008 0.168P + 0.008 0.08P + 0.008

0.32P + 0.012

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

9



s

0.080 0.090

UNM UNM

UNM UNM UNM UNM

UNM UNM UNM UNM

UNM UNM UNM UNM

0.30 0.35

0.40 0.45 0.50 0.55

0.60 0.70 0.80 0.90

1 .OO 1.10 1.20 1.40

1.000 1.100 1.200 1.400

0.600 0.700 0.800 0.900

0.400 0.450 0.500 0.550

0.300 0.350

Max., mm

0.964 1.064 1.164 1.358

0.036 0.036 0.036 0.042

0.024 0.027 0.030 0.033

0.018 0.018 0.021 0.021

0.382 0.432 0.479 0.529 0.576 0.673 0.770 0.867

0.016 0.017

Tol., mm

0.284 0.333

Min., mm

Diameter

0.483 0.564 0.646 0.728 0.810 0.910 1.010 1.173

0.838 0.938 1.038 1.205

NOTE: (1) Dimension

is used

in the

design

of tools.

0.319 0.369 0.401 0.451

0.503 0.586 0.670 0.754

0.335 0.385 0.419 0.469

0.234 0.277

0.248 0.292

Generally,

diameter

that

Diameter Min., mm

Pitch

Threads

Max., mm

I-

GENERAL NOTES: (a) For inch conversion of Table 6, see Appendix D. (b) Sizes shown in bold type are preferred. It is recommended

0.250 0.250 0.250 0.300

0.150 0.175 0.200 0.225

0.100 0.100 0.125 0.125

Pitch, mm

Size Designation

Major

External

acceptance

selection

0.028 0.028 0.028 0.032

0.020 0.022 0.024 0.026

0.016 0.016 0.018 0.018

0.014 0.015

Tol., mm

r

is based

upon

t

sizes

0.760 0.860 0.960 1.112

0.456 0.532 0.608 0.684

0.304 0.354 0.380 0.430

insofar

0.852 0.952 1.052 1.220

0.516 0.600 0.684 0.768

0.348 0.398 0.432 0.482

0.266 0.305

Max., mm

0.092 0.092 0.092 0.108

0.060 0.068 0.076 0.084

0.044 0.044 0.052 0.052

0.037 0.041

Tol., mm

condition

as possible.

Diameter

material

Minor

0.223 0.264

Min., mm

maximum

to these

0.666 0.766 0.866 1 .ooo

0.396 0.464 0.531 0.598

0.261 0.311 0.329 0.379

0.187 0.225

Min. II), mm

Diameter

be confined

0.714 0.814 0.914 I .056

0.428 0.500 0.571 0.642

0.285 0.335 0.357 0.407

0.208 0.247

Max., mm

Minor

r

TABLE 6 LIMITS OF SIZE AND TOLERANCES

gaging,

0.838 0.938 1.038 1.205

0.503 0.586 0.670 0.754

0.335 0.385 0.419 0.469

0.248 0.292

Min., mm

r Pitch

Internal

0.866 0.966 1.066 1.237

0.523 0.608 0.694 0.780

0.351 0.401 0.437 0.487

0.262 0.307

Max., mm

Diameter

Threads

0.028 0.028 0.028 0.032

0.020 0.022 0.024 0.026

0.016 0.016 0.018 0.018

0.014 0.015

Tol., mm

Major

1 .ooo 1.100 1.200 1.400

0.600 0.700 0.800 0.900

0.400 0.450 0.500 0.550

0.300 0.350

Min., mm

r

(1).

1.050 1.150 1.250 1.458

0.633 0.737 0.842 0.946

0.425 0.475 0.529 0.579

0.321 0.373

Max.

Diameter

0

5 5 iF

P G 5

i

W

0 -d ln -0 o-

I

ASME B1.10M-1997


r

U

m

L

5 m

E

al c

.-

5

.-O

.-ôm E

.-u v]

m

al X

O L

al al

c

5 .-5

c

U

E c

al

al al

.-

m

L

L

al al

2 r, -

L

O

L

U

al

c

'I2tolerance on major diameter of externalthread

U

U

U

L

.-ô

?

i E

.-X

,m

r, -

5 -

E al

E al c .-C

m

5E 5 E

Y

X

._ c

.I r

'/2

minor diameter tolerance on external thread

al c

O L

c

O L

al al

E

.-

U

U

L

O

.-c

E

6

E, L

O

.-C

E E

E .-

.-

r"

2

Y

FIG. 3 DISPOSITION OF TOLERANCES AND CRESTCLEARANCES


m

CI

.-m

II

?

al

c

External Thread [Screw)

U

m

X

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 specificationsfor gages for UnifiedMiniatureScrew Threads isnotwithinthe in the absence of scope of thisdocument.However, a gage standard, the development of which is awaiting theaccumulation of more experience with this thread standard,thereispresentedbelow, i n Fig. A l , an illustration of a chart which has beenfoundvery satisfactory for the optical projection method of inspection of external threads. Inspection at amagnification of lOOX isrecommended and atthisscalethe charts should be accurate to within +0.01 in. on all diameters and on pitchescumulatively up to fivepitches.

13


Maximum envelope Limits Minimum major Minimum Pitch

--

Minimum minor 0.80 U N M External Thread 1oox

Minor diameter Pitch diameter Major diameter

I

. Set-up

FIG. A l EXAMPLE OF PROJECTIONCOMPARATORCHARTFOREXTERNAL 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.)



z

0.006890 0.007874 0.008858 0.009843 0.011811

145 7, 127 1128/, 101 "/5 84 T3

1

0.005967 0.006819 0.007672 0.008524 0.010229

0.002728 0.003069 0.003409 0.004262 0.005114

Height of Sharp V, H= 0.8660254OP

Thread

GENERAL NOTE: For standardization, thread values based on a functional

0.003150 0.003543 0.003937 0.00492 0.005906

Pitch, P

317 '/2 28279 254 203 ?I 169 5;

Threads Per Inch, n

Basic

0.002237 0.002557 0.002877 0.003196 0.003836

0.001023 0.001151 0.001278 0.001598 0.001918

Dedendum of Internal Thread and Addendum of External Thread, 0.375 H = 0.32475953P

established

0.003945 0.004509 0.005072 0.005636 0.006763

0.001804 0.002029 0.002254 0.002818 0.003381

Height, 0.661H = 0.57259074P

Extern

Desic

based

of pitch,

0.0013 0.0015 0.0017 0.0018 0.0022

0.0006 0.0007 0.0007 0.0009 0.0011

Radius at Root, rrs = 0.18518149P

Form

on a function

0.00086 0.00098 0.00111 0.00123 0.00148

0.00039 0.00044 0.00049 0.00061 0.00074

Flat at Crest, Fcs = 0.12500000P

Thread

TABLE Bl FORM DIMENSIONS, BASIC AND DESIGN -r

this Table of thread values has been height, H, are used as reference only.

0.003307 0.003780 0.004252 0.004724 0.005669

0.001512 0.001701 0.001890 0.002362 0.002835

Height of internal Thread and Depth of Thread Engagement, 0.554H = 0.48OOOOOOP

Form

THREAD

P. The

0.003556 0.004064 0.004572 0.005080 0.006096

0.001626 0.001829 0.002032 0.002540 0.003048

Bounded Root Height, 0.596 H = 0.51808439P

Intern

Desig

0.00221 0.00252 0.00284 0.00316 0.00379

0.00101 0.00114 0.00126 0.00158 0.00189

Flat at Crest, Fen = 0.32074374P

Thread

0.0005 0.0006 0.0006 0.0007 0.0009

0.0002 0.0002 0.0003 0.0004 0.0004

Radius at Root, rm = 0.07216878P

Form

APPENDIX C INCH CONVERSION OF TABLE 4 (This Appendix is not part of ASME B1.10M-I997 and is included for information only.)

17



z

UNM UNM UNM UNM

1 .oo 1.10 1.20 1.40

NOTE:

UNM UNM UNM UNM

0.60 0.70 0.80 0.90


UNM UNM UNM UNM

UNM UNM

0.40 0.45 0.50 0.55

0.30 0.35

Size Designation

Sizes

shown

102 102 102 85

169 145 127 *13

254 254 203 203

318 282

Threads Per Inch,

n

in bold

type

0.0394 0.0433 0.0472 0.0551

0.0236 0.0276 0.0315 0.0354

0.0157 0.0177 0.0197 0.0217

0.0118 0.0138

in.

are

preferred.

Basic Major Diameter, 0, d

It is recommended

0.0330 0.0369 0.0409 0.0474

0.0198 0.0231 0.0264 0.0297

0.0132 0.0152 0.0165 0.0185

0.0668 0.0115

in.

4.4

Basic Pitch Diameter,

that

selection

0.0281 0.0320 0.0360 0.0416

0.0169 0.0197 0.0225 0.0253

0.0112 0.0132 0.0141 0.0160

0.0082 0.0097

in.

Minor Diameter External Threads, d,-1.14518k 4

be confined

to these

0.0299 0.0339 0.0378 0.0438

0.0180 0.0209 0.0239 0.0269

0.0120 0.0139 0.0150 0.0169

0.0088 0.0104

in.

Minor Diameter Internal Threads, D,-0.96P

TABLE Cl THREAD SIZE DIMENSIONS, BASIC AND DESIGN

sizes

insofar

0.0394 0.0433 0.0472 0.0551

0.0236 0.0276 0.0315 0.0354

0.0157 0.0177 0.0197 0.0217

0.0118 0.0138

in.

Nominal Major Diameter Internal Threads, D

5 4 4 4

5 5 5 5

5 4 5 4

5 5

deg

26 51 23 32

28 26 26 26

26 44 26 51

52 37

min

Lead Angle at Basic Pitch Diameter, A

x 10-4

x 1O-5

6.21 8.07 1.02 x 10-3 1.36

2.23 3.04 3.97 5.02

9.88 1.37 1.55 2.02

5.27 7.43

sq in.

Sectional Area Minor Diameter D-1.14518P

at 4,

z

VI -I W .

APPENDIX D INCH CONVERSION OF TABLE 6 (This Appendix is not part of 6l.lOM-1997 and is included for information only.)



g

NOTE: (1) Dimension

NOTE:

102 102 102 85

1.00 UNM 1.10 UNM 1.20 UNM 1.40 UNM


169 145 127 113

UNM UNM UNM UNM

0.60 0.70 0.80 0.90

is used

Sizes

254 254 203 203

UNM UNM UNM UNM

0.40 0.45 0.50 0.55

318 282

UNM UNM

0.30 0.35

Size Designation

Threads Per Inch

in the

shown

type

0.0330 0.0367 0.0409 0.0474

0.0198 0.0231 0.0264 0.0297

0.0132 0.0152 0.0165 0.0185

0.0098 0.0115

Max., in.

T

Generally

are preferred.

0.0014 0.0014 0.0014 0.0016

of tools.

0.0380 0.0419 0.0458 0.0535

0.0009 0.0011 0.0012 0.0013

0.0007 0.0007 0.0008 0.0009

0.0150 0.0170 0.0189 0.0208 0.0227 0.0265 0.0303 0.0341

0.0006 0.0007

Tol., in.

0.0112 0.0131

Min., in.

Diameter

in bold

design

0.0364 0.0433 0.0472 0.0551

0.0236 0.0276 0.0315 0.0354

0.0157 0.0177 0.0197 0.0217

0.0118 0.0138

Max., in.

Major

0.0011 0.0011 0.0012 0.0012

0.0008 0.0009 0.0010 0.0010

0.0006 0.0007 0.0667 0.0008

0.0006 0.0006

Tol., in.

acceptance

It is recommended

0.0319 0.0358 0.0397 0.0462

0.0190 0.0222 0.0254 0.0287

0.0126 0.0145 0.0158 0.0177

0.0092 0.0109

Min., in.

Diameter

Threads

diameter

Pitch

External

in.

0.0262 0.0302 0.0341 0.0394

0.0156 0.0183 0.0209 0.0235

0.0103 0.0122 0.0130 0.0149

upon

f

0.0299 0.0339 0.0378 0.0438

0.0180 0.0209 0.0239 0.0269

0.0124 0.0139 0.0150 0.0169

maximum

to these

0.0335 0.0375 0.0414 0.0480

0.0203 0.0236 0.0289 0.0302

0.0137 0.0157 0.0170 0.0190

0.0102 0.0120

Max., in.

sizes

0.0636 0.0036 0.0036 0.0042

0.0023 0.0027 0.0030 0.0033

0.0017 0.0018 0.0020 0.0021

0.0014 0.0016

Tol., in.

condition

Diameter

material

Minor

0.0088 0.0104

Min., in.

be confined

(I),

0.0074 0.0089

Min.

Diameter

selection

is based

that

0.0281 0.0320 0.0360 0.0416

0.0169 0.0197 0.0225 0.0258

0.0112 0.0132 0.0141 0.0160

0.0062 0.0097

Max., in.

Minor

TABLE Dl LIM-ITS OF SIZE AND TOLERANCES

Min., in.

Pitch

gaging.

insofar

0.0330 0.0367 0.0409 0.0474

0.0198 0.0231 0.0264 0.0297

0.0132 0.0152 0.0165 0.0185

0.0098 0.0115

T

Internal

0.0341 0.0380 0.0426 0.0487

0.0206 0.0240 0.0273 0.0307

0.0138 0.0158 0.0172 0.0192

0.0104 0.0121

Max., in.

Diameter

Threads

0.0011 0.0011 0.0011 0.0013

0.0008 0.0009 0.0009 0.0010

0.0006 0.0006 0.0007 0.0007

0.0006 0.0006

Tol., in.

Min., in.

Major

0.0394 0.0433 0.0472 0.0551

0.0236 0.0276 0.0315 0.0354

0.0157 0.0177 0.0197 0.0217

0.0118 0.0138

L

T

in.

0.0413 0.0453 0.0492 0.0574

0.0249 0.0290 0.0331 0.0372

0.0167 0.0187 0.0208 0.0228

0.0126 0.0147

Max.

Diameter (11,

ASME B1.10M

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