1、 Intentionally left blank AN AMERICAN NATIONAL STANDARD Gages and Gaging for MJ Series Metric Screw Threads ANWASME 61.22M - 1985 (REVISION OF ANSI B1.22-1978) SPONSORED AND PUBLISHED BY THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS United Engineering Center 345 East 47th Street New York, N. Y. 10017
2、 Date of Issuance: December 31, 1986 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. This code or standard was developed under procedures accredited
3、 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 oppor- tunity to participate. The proposed code or standard was made available for public re
4、view and comment which provides an opportunity for additional public input from industry, academia, reg- ulatory 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 t
5、he 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 expressl
6、y advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, is entirely their own responsibility. Participation by federal agency representative(s) or person(s) affiliated with industry is not to be interpreted as government or industry endors
7、ement of this code or standard. ASME accepts responsibility for only those interpretations issued in accordance with governing ASME procedures and policies which preclude the issuance of interpretations by individual vol- unteers. No part of this document may be reproduced in any form, in an electro
8、nic retrieval system or otherwise, without the prior written permission of the publisher. Copyright 0 1986 by THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS All Rights Reserved Printed in U.S.A. FOREWORD (This Foreword is not part of ANSVASME B1.22M-1985.) American National Standards Committee Bl for
9、the standardization of screw threads was organized in 1920 as Sectional Committee Bl under the aegis of the American Engineering Standards Committee later the American Standards Association, then the United States of America Standards Institute, and as of October 6, 1969, the American National Stand
10、ards Institute, Inc. (ANSI), with the Society of Automotive Engineers and the American Society of Mechanical Engineers as joint sponsors. As a result, a great deal of effort was expended through the years toward development of several inch screw thread standards, including the current inch gaging st
11、andard, ANSVASME B1.2-1983, Gages and Gaging for Unified Inch Screw Threads. Recognizing the increasing need of industries in the United States for documentation of American gaging practice for metric screw threads, American National Standards Committee Bl charged its thread gaging Subcommittee 2 wi
12、th the responsibility for producing such a standard. ANSI Bl. 16-1972 was developed as a standard for American gaging practice for metric screw threads; ANSVASME Bl.l6M-1984 is a revision of that standard. With the development of the MJ series of metric screw threads, documented in ANSI B1.2 1, it b
13、ecame necessary to document the required thread gages that were not covered in the ANSI Bl .16 standard. Committee Bl asked Subcommittee 2 to develop such a standard. ANSI B1.22-1978 was developed by Subcommittee 2 to provide the essential specifications for gages and gaging practice necessary to fu
14、lfill the provisions of the product thread document ANSI B1.21, Metric Screw Threads - MJ Profile. In 1982, Committee Bl was reorganized as the ASME Standards Committee Bl, and it has operated under American Society of Mechanical Engineers procedures to produce and update standards which become ANSI
15、 Standards after final approval by the American National Stan- dards Institute. This publication, designated ANSVASME B1.22M-1985, does not have any references to conformance criteria, as Committee Bl has established B1.3M for all levels of acceptability for screw threads. A considerable amount of n
16、ew material is added to cover the many options of gages and measuring equipment shown in B1.3M. Mn/Mt gages have been identified as NOT GO gages. The proposed Standard was submitted by the ASME Board of Standardization to the Amer- ican National Standards Institute. It was approved and formally desi
17、gnated as an American National Standard on September 26, 1985. . . . 111 Intentionally left blank ASME STANDARDS COMMITTEE Bl Standardization and Unification of Screw Threads (The following is the roster of the Committee at the time of approval of this Standard.) OFFICERS D. J. Emanuelli, Chairman H
18、. W. Ellison, Vice Chairman C. E. Lynch, Secretary COMMITTEE PERSONNEL AEROSPACE INDUSTRIES ASSOCIATION OF AMERICA, INC. G. G. Gerber, McDonnell Douglas, St. Louis, Missouri H. Bonman, Alternate, Sperry Gyroscope Division, Great Neck, New York AMERICAN IRON AND STEEL INSTITUTE F. Dallas, Jr., Cyclop
19、s Corp., Sharon, Pennsylvania AMERICAN MEASURING TOOL MANUFACTURERS ASSOCIATION D. Dodge, Pennoyer-Dodge Co., Glendale, California C. W. Jatho, Alternate, American Measuring Tool Manufacturers Association, Birmingham, Michigan AMERICAN PIPE FITTINGS ASSOCIATION W. C. Farrell, Jr., Stockham Valves an
20、d Fittings, Inc., Birmingham, Alabama DEFENSE INDUSTRIAL SUPPLY CENTER E. Schwartz, Defense Industrial Supply Center, Philadelphia, Pennsylvania F. S. Ciccarone, Alternate, Defense Industrial Supply Center, Philadelphia, Pennsylvania ENGINE MANUFACTURERS ASSOCIATION G. A. Russ, Cummins Engine Co., C
21、olumbus, Indiana FARM AND INDUSTRIAL EQUIPMENT INSTITUTE J. F. Nagy, Ford Motor Co., Dearborn, Michigan INDUSTRIAL FASTENERS INSTITUTE R. 6. Belford, Industrial Fasteners Institute, Cleveland, Ohio R. M. Harris, Bethlehem Steel Co., Lebanon, Pennsylvania K. E. McCullough, SPS Technologies, Inc., Jen
22、kintown, Pennsylvania J. C. McMurray, Russell, Burdsall and Ward, Inc., Mentor, Ohio MANUFACTURERS STANDARDIZATION SOCIETY OF THE VALVE AND FITTINGS INDUSTRY W. C. Farrell, Jr., Stockham Valves and Fittings, Inc., Birmingham, Alabama METAL CUTTING TOOL INSTITUTE (TAP (b) 20C + 1C (68F *2”F) for size
23、s above 25 mm to 75 mm; (c) 20C +0.5”C (68F fl”F) for sizes above 75 mm to 150 mm at the time of gaging. See Appendix E covering temperature corrections for various materials. 2.5 Rounding Procedures 2.5.1 Rounding Procedure for Converting Met- ric Gage Values to Inch Gage Values. Determine metric g
24、age dimensions from gage specifications. Cal- culate the inch gage size by dividing the metric gage size (given to three decimal places) by 25.4. Round to five decimal places by the following method. When the first digit discarded is less than 5, the last digit retained should not be changed. If the
25、 first discarded digit is greater than 5, or if it is a 5 followed by at least one digit other than 0, the last figure retained should be increased by one unit. If the first discarded digit is a 5 followed by only zeros, the last digit retained should be rounded upward if it is an odd number, but no
26、t changed if it is an even number. Metric dimensions are official values, and all inch tables shown in Appendix D are for reference only. EXAMPLES OF ROUNDING: 6.431243182 is rounded to 6.43724 6.437246643 is rounded to 6.43725 6.437245001 is rounded to 6.43725 6.437255000 is rounded to 6.43726 6.43
27、7245000 is rounded to 6.43724 2.6 Identification Thread gages which are used interchangeably for reg- ular metric M as well as MJ series metric screw threads and which are made to ANSIlASME Bl. 16M may be marked to specifications in that standard. 3 GENERAL PRACTICE 3.1 General Design The design of
28、gages is specified only to the extent that it affects the results obtained in the gaging of product threads. Moreover, to serve their intended purposes sat- isfactorily, thread gages should be produced by the latest and best manufacturing techniques. The type of steel or 10 GAGES AND GAGING FOR MJ S
29、ERIES METRIC SCREW THREADS wear-resistant material selected, together with the heat- treating and stabilization processes, should provide wear life and dimensional stability. Thread gaging elements should be precisely manufactured to assure adequate re- finement of surface texture, prevention or eli
30、mination of amorphous or smear metal, and uniformity of thread form over the entire length of the gaging member. 3.2 Types of Gages GO thread gages check either the maximum-material limit or size to assure interchangeable assembly. NOT GO thread gages inspect the NOT GO functional di- ameter limit.
31、GO and NOT GO plain cylindrical plug or ring gages and snap or indicating gages check the limit or size of the minor diameter of product internal threads and the major diameter of product external threads, respectively. 3.3 lnterpretation of Tolerances Tolerances on lead, half-angle, and pitch diame
32、ter are variations which may be taken independently for each of these elements and may be taken to the extent allowed by respective tabulated dimensional limits. The tabulated tolerance on any one element must not be exceeded even though variations in the other two elements are smaller than the resp
33、ective tabulated tolerances. 3.4 Direction of Tolerances on Gages At the maximum-material limit (GO), the dimensions of all gages used for final conformance gaging are within the limits of size of the product thread. At the functional diameter limit, using NOT GO gages, the standard prac- tice is to
34、 have the gage tolerance within the limits of size of the product thread. Specifications for gage limits are listed in Tables 7 and 8. 3.5 Standard Thread Gage Tolerances Standard tolerances for thread-working gages, thread- setting plugs, and setting rings are as follows: (a) W tolerances, shown in
35、 Table 10, represent the highest commercial grade of accuracy and workmanship and are specified for thread-setting gages; (6) X tolerances, shown in Table 9, are larger than W tolerances and are used for product inspection gages. Unless otherwise specified, all thread gages and gag- ing contacts whi
36、ch directly check the product thread shall be X tolerance. ANSllASME B1.22M-1985 AN AMERICAN NATIONAL STANDARD 3.6 Tolerance on Lead The cumulative effect of progressive or erratic helix variation and thick or thin end thread variation is spec- ified as an allowable variation between any two threads
37、 not farther apart than the length of the standard taperlock or trilock gage shown in ANSI/ASME E547.laM. In the case of setting plugs, the specified tolerance shah be applicable to the thread length in the mating ring gage or nine pitches, whichever is smaller. For setting rings, the tolerance appl
38、ies to a thread length of three pitches. The tolerance on lead establishes the width of a zone, measured parallel to the axis of the thread, within which the actual helical path must lie for the specified length of the thread. Measurements will be taken from a fixed reference point located at the st
39、art of the first full thread to a sufficient number of positions along the entire helix to detect all types of lead variations. The amounts that these positions vary from their basic (theoretical) posi- tions will be recorded with due respect to sign. The greatest variation in each direction, plus o
40、r minus (?), will be selected and the sum of their values, disregarding sign, shall not exceed the specified tolerance. If the vari- ations are all in one direction, the maximum value gov- ems conformance. In the case of truncated setting plugs, the lead variations present on the full-form portion a
41、nd the truncated portion of an individual gage shall not dif- fer from each other by more than 0.003 mm over any portion equivalent to the length of the thread ring gage, or nine pitches, whichever is less. (When linear lead and drunkenness are measured as individual elements and the sum of these do
42、es not exceed the tolerance specified, the gage is well within tolerance.) 3.7 Tolerances on Half-Angle Tolerances are specified for the half-angle rather than the included angle to assure that the bisector of the in- cluded angle will be perpendicular to the axis of the thread within proper limits.
43、 The equivalent of the vari- ation from the true thread form caused by such irregu- larities as convex, concave, or wavy flanks, rounded crests, or slight projections on the thread form shall not exceed the tolerance permitted on half-angle. 3.8 Check of Effect of Lead and Flank Angle Variations on
44、Product Thread When this check is specified, there are two general methods available for the inspection procedures in- volved. (a) Direct Measurement of Lead and Half-Angle of Fhks. The lead and flank angles of the product thread may be measured by means of available measuring I1 ANSVASME B1.22M-198
45、5 GAGES AND GAGING FOR AN AMERICAN NATIONAL STANDARD MJ SERIES METRIC SCREW THREADS equipment such as projection comparators, measuring maximum-material limit of the product internal thread, microscopes, graduated cone points, lead measuring ma- chines, helix variation measuring machines, thread fla
46、nk and the gaging length is equal to the length of the gaging plug. charting equipment, etc. Diameter equivalents of such variations from nominal may be calculated. Each 0.0025 mm variation in lead amounts to a 0.0043 mm (1.732 x 0.0025) increase in functional pitch diameter on ex- ternal threads or
47、 a decrease in functional pitch diameter on internal threads for 60 deg. screw threads. The tan- gent of half-angle variation times 1.5P equals the ap- proximate maximum change in functional pitch diameter with equal half-angle variations. 4.1.3 Gage Blanks. For practical and economic reasons, the d
48、esign and lengths of the gaging plug mem- bers have been standardized for various size ranges and pitches (see ANSUASME B47.laM or Table C2). 4.1.4 Thread Form. The specifications for thread form are summarized in Table 7 and Fig. 1. 4.1.5 Thread Crests. The major diameter of the GO thread plug gage
49、 shall be the same as the minimum major diameter of the product internal thread, with a plus gage tolerance. The thread crests shall be flat in an axial section and parallel to the axis. (b) Differential Gaging Utilizing Indicating i%read Gages. See Sections 4 and 5 for explanation and illus- tration of differential gaging for internal and external threads. 3.9 Calibration Requirements and Standards Calibration requirements and standards for X tolerance thread gages, snap gages, indicating gages, Z toleranc
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