1、I I I COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services The American Society of Mechanical Engineers AN AMERICAN NATIONAL STANDARD A C M E SCREW A S M E B1.54 997 (

2、Revision of ASMUANSI 61.5-1 988) COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services STDmASME 61-S-ENGL 1997 9 O759670 Ob15362 9L5 m Date of Issuance: December 6, 199

3、9 The 1997 edition of this Standard is being issued with an automatic addenda subscription service. The use of an addenda allows revisions made in response to public review comments or committee actions to be published as necessary. The next edition of this Standard is scheduled for publication in 2

4、002. 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 Standards Committee that approved the code or standard was balanced to assure that indiv

5、iduals 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 do

6、es 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 a

7、gainst liabilityfor infringement of any applicable Letters Patent, nor assume any such liability. Users of a code or standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, is entirely their own responsibility. Partici

8、pation by federal agency representativek) or person(s) 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 pre

9、clude 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 Three Park Avenue, New York, NY

10、10016-5990 Copyright O 1999 by THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS All Rights Reserved Printed in U.S.A. COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services

11、FOREWORD When created prior to 1895, Acme screw threads were intended to replace square threads and a variety of threads of other forms used chiefly for the purpose of traversing motion on machines, tools, etc. Acme screw threads are now extensively used for a variety of purposes. Long-length Acme t

12、hreads are used for controlled movements on machine tools, testing machines, jacks, aircraft flaps, and conveyors. Short-length threads are used on valve stems, hose connectors, bonnets on pressure cylinders, steering mechanisms, and camera lens movement. The Standards Committee on the Standardizati

13、on and Unification of Screw Threads, B 1, was organized in June 1921, with the Society of Automotive Engineers and the American Society of Mechanical Engineers as joint sponsors under the procedure of the American Standards Association (ASA), now the American National Standards Institute (ANSI). Thi

14、s Committee was reorganized in May 1929, and its work was divided among five Subcommittees as follows: No. 1 on Scope and Arrangement of American Standard; No. 2 on Terminology and Form of Thread, Except Gages; No. 3 on Special Threads and Twelve Pitch Series, Except Gages; No. 4 on Acme Threads, Ex

15、cept Gages; and No. S on Screw Thread Gages. National standardization of Acme screw threads in the United States was begun in 1932 when Subcommittee No. 4 on Acme Threads of Standards Committee BI held its first meeting in New York. A report was presented on the types of Acme threads and the range o

16、f sizes and pitches in use in this country. It was prepared by C. W. Bettcher with the assistance of F. L. Woodcock. This report developed into a draft standard and was finally approved as an American Standard with the designation ASA B 1.3- 1941. It contained a section of introductory notes, and ta

17、bles covering general purpose screws and general purpose nuts, basic dimensions of general purpose Acme threads with special and standard pitches, basic dimensions of 29 deg stub thread, measurements over three wires for Acme threads, basic dimensions of 60 deg stub thread, and basic proportions for

18、 modified square thread. In December 1942, to meet the war emergency, the National Aircraft Standards Committee of the Aeronautical Chamber of Commerce requested the ASA to consider the setting up of an American War Standard for special Acme screw threads for use in aircraft construction. Recognizin

19、g the vital importance of aircraft production to the war effort, the ASA initiated this project at once and organized a Special Committee to develop the Standard. Drafts of this proposed American War Standard were submitted, first on behalf of the National Aircraft Standards Committee and later by D

20、. R. Miller of the National Bureau of Standards. The latter draft, which was submitted also to the Interdepartmental Screw Thread Committee established by the U.S. Departments of War, Navy, and Commerce, served as the basis for the development of the American War Standard. The final draft, dated Nov

21、ember 20, 1944, was unanimously approved by the members of the ASA War Committee on Acme Threads and the General ASA War Committee on Screw Threads. This draft received final ASA approval on January 9, 1945, and was designated American War Standard BIS-1945. In April 1946, the Subcommittees of the S

22、tandards Committee were reorganized to take over the job of the ASA War Committees. Subcommittee No. 2 on Acme and Stub Acme Threads revised the War Standard on Acme Screw Threads and, on March 3 1, 1948, distributed the January 1948 draft to industry for criticism and comment. . 111 COPYRIGHT Ameri

23、can Society of Mechanical Engineers Licensed by Information Handling Services COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services The final draft of the proposed revision to the 1945 Edition of this Standard was completed in June 195 1. It was submitted to St

24、andards Committee B 1 for letter ballot on September 17, 1951, and was approved with minor amendments. Following approval by the sponsor organizations, the proposed Standard was submitted to the ASA for approval and designation as an American Standard. This was granted May 7, 1952. The next revision

25、 added the no allowance Class 5G thread. Approval by ANSI was granted on March 26, 1973. Corrections were made in the revision approved May 11, 1977. Data for Classes 5G, 5C, and 6G was transferred to Appendices D and E for reference, and this revision was approved by ANSI on January 11, 1988. The p

26、resent revision to the Standard includes the addition of gage tables and drawings for Gaging Systems 21, 22, and 23, table changes to conform to ASME B1.30M, lead and angle tolerances for product threads, measurement uncertainty values for Acme thread gages, and descriptions and drawings for indicat

27、ing gages. The pitch diameter compensation table and text were deleted and replaced with data on standard gage blanks for gage length with text on pitch diameter adjustment for gage length over two diameters. Table values of gage dimensions for general purpose and centralizing Acme threads were adde

28、d, along with formulas to determine diameters of multiple-start threads. Recommendation in the use of formulas and examples to calculate pitch diameter measurement over wires was revised. Additionally, the Appendix contains revision of alternate centralizing Acme threads and of multiple-start thread

29、s, and was expanded to include ball measurement of internal pitch diameter, limit gaging of setting ring gages, gaging of problem areas, Acme tolerances over 5 in., and means for determining limits of size for special diameterlpitch combinations. This Standard was approved by the American National S

30、tandards Institute on December 9. 1997. COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services ASME STANDARDS COMMITTEE B1 Screw Threads (The following is the roster of

31、the Committee at the time of approval of this Standard.) OFFICERS A. D. Shepherd, Chair J. Bird, Secretary COMMITTEE PERSONNEL J. R. Anderson, Delphi Harrison Thermal System J. Bird, The American Society of Mechanical Engineers J. M. Bobelak. Boeing R. M. Byrne, Trade Association Management, Inc. D.

32、 P. Cadieux, Glastonbury Gage F. G. Calderone, Quality Systems lmplementers R. Dodge, Pennoyer-Dodge Co. A. E. Ellis, Retired H. W. Ellison, Consultant R. E. Ferry, R. B. Order Department: 22 Law Drive, Box 2300, Fairfield, NJ 07007-2300 1.4 Reference Temperature The reference temperature is 68F (20

33、C) for dimen- sions listed. 1.5 Units of Measure All dimensions and values are expressed in inches unless otherwise noted. 1.6 Terminology Definitions, terms, and symbols relating to Acme screw threads are found in ASME B 1.7M. Explanation of IS0 fundamental deviation symbols used for allow- ance in

34、 this Standard are: El: lower deviation, internal thread allowance (funda- mental deviation). es: upper deviation, external thread allowance (funda- mental deviation); es is always negztive for an allowance fit or zero for no allowance. 1.7 Computer-Generated Size All computer-generated values for s

35、tandard sizes herein are identical to previous Acme publications. For a nonstandard nominal size, D, apply the next larger nominal size given in the table. For computer calculation of Acme product and gage size or tolerance, use ASME B1.30M and formulas herein. Parties should be advised in contract.

36、 2 SPECIFICATIONS FOR GENERAL PURPOSE ACME SCREW THREADS 2.1 Angle of Thread The included angle between the flanks of the thread, measured in an axial plane, shall be 29 deg. The line bisecting this 29 deg angle shall be perpendicular to the axis of the screw thread. 2.2 Pitch and Lead of Thread ACM

37、E SCREW THREADS distance traversed in one revolution of a screw thread. On multiple-start threads, the lead equals pitch multiplied by the number of starts. 2.3 Height of Thread The basic height of the thread is equal to one-half of the pitch. 2.4 Thickness of Thread The basic thickness of the threa

38、d profile at the pitch line is one-half of the pitch. 2.5 Allowance (Minimum Clearance) at Major and Minor Diameters A minimum diametral clearance is provided at the minor diameter of all threads by establishing the maxi- mum minor diameter of the external thread 0.020 in. less than the basic minor

39、diameter for 10 threaddin. and coarser, and 0.010 in. less for finer pitches. A minimum diametral clearance at the major diameter is obtained by establishing the minimum major diameter of the internal thread 0.020 in. greater than the basic major diameter for 10 threaddin. and coarser, and 0.010 in.

40、 greater for finer pitches. 2.6 Chamfers and Fillets External threads may have the crest comers chamfered at an angle of 45 deg with the axis to a maximum depth of P/15. This corresponds to a maximum width of chamfer flat of 0.0949. The internal and external threads may have optional fillets; see Fi

41、g. 3. 2.7 Basic Thread Form Dimensions The basic dimensions of the Acme thread form for the most generally used pitches are given in Table 1. The basic thread profile is symmetrical and is illustrated in Fig. 1. Design profiles are shown in Fig. 2. 2.8 General Purpose Standard Acme Thread Series A s

42、elected series of diameters and associated pitches of Acme threads, listed in Table 2, are recommended as preferred. These diameters and pitches have been carefully selected to meet present needs with the fewest The pitch of the thread is the distance, measured number- of items in order t o reduce t

43、o a minimum the parallel to its axis, between corresponding points on inventory of both tools and gages. For sizes over 5 adjacent thread forms. The lead of a thread is the in., see Appendix H. 2 COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services COPYRIGHT A

44、merican Society of Mechanical Engineers Licensed by Information Handling Services ACME SCREW THREADS ASME 81.5-1997 TABLE 1 GENERAL PURPOSE ACME SCREW THREAD FORM, DESIGN DIMENSIONS Width of Flat at: Height of Total Height of Thread Threads1 Thread Thread, Thickness Crest of Internal Root of Interna

45、l Thread, m., Pitch, Basic), h, = h + /* Allowance (Basic), Thread (Basic), F, = 0.3707 P - 0.259 n P h = Pl2 Note (111 t = Pl2 F, = 0.3707 P x Allowance Note (111 16 0.06250 0.03125 0.0362 0.03125 0.0232 0.0206 14 0.07143 0.03571 0.0407 0.03571 0.0265 0.0239 12 0.08333 0.04167 0.0467 0.04167 0.0309

46、 0.0283 10 o. 1 O000 0.05000 0.0600 0.05000 0.0371 0.0319 8 0.12500 0.06250 0.0725 0.06250 0.0463 0.041 1 6 O. 16667 0.08333 0.0933 0.08333 0.0618 0.0566 5 0.20000 o. 1 O000 0.1100 o. 1 O000 0.0741 0.0689 4 0.25000 0.12500 0.1350 0.1 2500 0.0927 0.0875 3 0.33333 O. 16667 0.1767 O. 16667 0.1 236 0.11

47、84 24 0.40000 0.20000 0.2100 0.20000 0.1483 0.1431 1 /2 0.66667 0.33333 0.3433 0.33333 0.2471 0.2419 1 / 3 0.75000 0.37500 0.3850 0.37500 0.2780 0.2728 2 0.50000 0.25000 0.2600 0.25000 O. 1853 O. 1802 1 1 .ooooo 0.50000 0.5 1 O0 0.50000 0.3707 0.3655 NOTE: (1) See Table 4. 2.9 Classification and Tol

48、erances, General Purpose Acme Threads There are established herein three classes of threads for general purpose: 2G, 3G, and 4G. These classes, together with the accompanying speci- fications, are for the purpose of ensuring interchangeabil- ity of Acme threaded parts. Each user is free to select th

49、e classes best adapted to his particular needs. It is suggested that external and internal threads of the same class be used together for general purpose assemblies, Class 2G being the preferable choice. If less backlash is desired, Classes 3G and 4G are provided. 2.10 Basic Diameters The maximum ma

50、jor diameter of the external thread is basic and is the nominal size for all classes. The minimum pitch diameter of the internal thread is basic and is equal to the basic major diameter minus the basic thread height, h. The basic minor diameter is the minimum minor diameter of the internal thread. I

51、t is equal to the basic major diameter minus twice the basic thread height, 2h. 2.11 Length of Engagement The tolerances specified herein are applicable to all lengths of engagement not exceeding twice the basic major diameter. 2.12 Tolerances 2.12.1 Tolerance Zone Definition. The definition of the

52、Acme thread is dimensioned by pitch diameter reference locations in perfect 29 deg thread forms with crest and root limited by the corresponding major and minor diameters with corner fillet limitations. This tolerance zone between the maximum and minimum thread profiles defines the thread. There are

53、 additional limitations, within the tolerance zone, on the elements flank angle and lead. 2.12.2 Tolerance Direction. The tolerances on diameters of the internal thread are plus, being applied from the minimum sizes to above the minimum sizes. The tolerances on diameters of the external threads are

54、minus, being applied from the maximum sizes to below the maximum sizes. 2.12.3 Tolerances on Major and Minor Diame- ters. The tolerances on major and minor diameters of external and internal threads are based on the data in Table 3; the values are listed in Table 4. 2.12.4 Tolerance on Pitch Diamete

55、r. The pitch diameter tolerances for an external and internal thread of a given class are the same. These tolerances determine the tolerance zone included between the maximum and minimum boundary limits. The tolerance Classes 2G, 3G, and 4G are given in Tables 5, 6, and 7. The ratio 3 COPYRIGHT Amer

56、ican Society of Mechanical Engineers Licensed by Information Handling Services COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services ASME B1.5-1997 ACME SCREW THREADS Dd 2 2 Dd I 1 1 Axis of thread - - D D1 D2 dl d2 P d h = basic major diameter, internal thread

57、 = basic minor diameter, internal thread = basic pitch diameter, internal thread = pitch = basic major diameter, external thread = basic minor diameter, external thread = basic pitch diameter, external thread = basic thread height FIG. 1 PROFILE FOR ACME SCREW THREAD 4 COPYRIGHT American Society of

58、Mechanical Engineers Licensed by Information Handling Services COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services ACME SCREW THREADS ASME B1.5-1997 basic width of flat of crest of internal thread 0.3707P width of flat of crest of external thread 0.3707P - 0.

59、259 X pitch diameter allowance on external thread 0.3707P - 0.259 X (major diameter allowance on internal thread) 0.3707P - 0.259 X (minor diameter allowance on external thread - pitch diameter allowance on external thread) pitch basic height of thread P12 number of threadslin. 14deg 30 min 29 deg FIG. 2 DESIGN PROFILE FOR EXTERNAL AND INTERNAL GENERAL PURPOSE ACME THREAD 5 COPYRIGHT American Society of Mechanical Engineers Licensed by I