1、 Intentionally left blank AN AMERICAN NATIONAL STANDARD Gages and Gaging for Metric M Screw Threads ANWASME Bl.l6M-1984 (REVISION OF ANSI B1.16-1972) SPONSORED AND PUBLISHED BY THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS United Engineering Center 345 East 47th Street New York, N. Y. 10017 Date of I
2、ssuance: April 30. 1985 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 as meeting t
3、he 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 review and comm
4、ent 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 the validity o
5、f 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 tha
6、t 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 endorsement of this
7、 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 electronic retrieval
8、 system or otherwise, without the prior written permission of the publisher. Copyright 0 1985 by THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS All Rights Reserved Printed in U.S.A. (This Foreword is not part of ANSI/ASME 81 .16M-1984.) The first issue of ANSI Bl. 16 was approved and formally designat
9、ed as an American National Standard on April 28, 1972. It was developed by Subcommittee 2 of the Bl Committee to serve as the American practice regarding the specifications and dimensions for gages applied to metric screw threads. As in the first issue, this Edition of ANSI Bl. 16M follows the Ameri
10、can practice for the design and tolerances for gages of this type, except for the truncations of the HI/LO elements, which are more in line with the truncations specified in IS0 1502. This new publication, designated ANSI! ASME Bl. 16M-1984, has had considerable new material added to cover the many
11、options of gages and measuring equipment shown in ANSI Bl.3M, Screw Thread Gaging Systems for Dimensional Acceptability. It has also retained HI and LO functional gages but has eliminated gages with pitch diameter outside product thread limits. It also includes tabulated values for the specification
12、s of gage elements for the standard series of metric M screw thread sizes listed in ANSI Bl. 13M, Metric Screw Threads - M Profile. ANSIjASME Bl.16M was approved by the ASME Standards Committee Bl on April 27, 1984. The proposed Standard was submitted by the ASME Board of Stan- dardization to the Am
13、erican National Standards Institute. It was approved and formally designated an American National Standard on May 25, 1984. . . . 111 Intentionally left blank ASME STANDARDS COMMITTEE 61 Standardization and Unification of Screw Threads (The following is the roster of the Committee at the time of app
14、roval of this Standard.) OFFICERS D. J. Emanuelli, Chairman H. 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. Borrman, Alternate, Sperry Gyroscope Division, Great Neck, New
15、 York AMERICAN IRON AND STEEL INSTITUTE F. Dallas. Jr., Sawhill Tubular Division, Sharon, Pennsylvania AMERICAN MEASURING TOOL MANUFACTURERS ASSOCIATION D. Dodge, Pennoyer-Dodge Co., Glendale, California C. W. Jatho, Akernate, American Measuring Tool Manufacturers Association, Birmingham, Michigan A
16、MERICAN PIPE FITTINGS ASSOCIATION W. C. Farrell, Stockham Valves and Fittings, Birmingham, Alabama DEFENSE INDUSTRIAL SUPPLY CENTER E. Schwartz, Defense Industrial Supply Center, Philadelphia, Pennsylvania F. S. Ciccarone, Alternate, Defense Industrial Supply Center, Philadelphia, Pennsylvania ENGIN
17、E MANUFACTURERS ASSOCIATION G. A. Russ, Cummins Engine Co., Columbus, Indiana FARM AND INDUSTRtAL EQUIPMENT INSTITUTE J. F. Nagy. Ford Motor Co., Dearborn, Michigan INDUSTRIAL FASTENERS INSTITUTE R. B. B (6) 20C (c) 20C +0.5”C (68F k 1F) for sizes above 75 mm to 150 mm. 2.5 Rounding Procedure for Co
18、nverting Met- ric Gage Values to Inch Gage Values Determine metric gage dimensions from gage specifications. Calculate the inch gage size by divid- ing 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 i
19、s less than 5, the last digit retained should not be changed. If the 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 di
20、git retained should be rounded upward if it is an odd number, but not changed if it is an even number. Metric dimensions are official values, and all inch tables shown in Appendix D are for reference only. GAGES AND GAGING FOR METRIC M SCREW THREADS EXAMPLES OF ROUNDING: 6.437243782 is rounded IO 6.
21、43724 6.437246643 is rounded lo 6.43725 6.437245001 is rounded to 6.43725 6.437255000 is rounded to 6.43726 6.437245ooO is rounded to 6.43724 3 GENERAL PRACTICE 3.1 General Design The design of gages is specified only to the extent that it affects the results obtained in the gaging of product thread
22、s. Moreover, to serve their intended purposes satisfactorily, thread gages should be pro- duced by the latest and best manufacturing tech- niques. The type of steel or wear-resistant material selected, together with the heat-treating and stabiliza- tion processes, should provide wear life and dimen-
23、 sional stability. Thread gaging elements should be precisely manufactured to assure adequate refine- ment of surface texture, prevention or elimination 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 ei
24、ther the maximum- material limit or size to assure interchangeable as- sembly. HI and LO thread gages inspect the HI and LO functional diameter limit. 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 thr
25、eads and the major diameter of product external threads, respectively. 3.3 interpretation of Tolerances Tolerances on lead, half-angle, and pitch diameter are variations which may be taken independently for each of these elements and may be taken to the extent allowed by respective tabulated dimensi
26、onal limits. The tabulated tolerance on any one element shall not be exceeded, even though variations in the other two elements are smaller than the respective tabulated tolerances. 3.4 Direction of Tolerances on Gages At the maximum-material limit (GO), the dimen- sions of all gages used for final
27、conformance gaging are to be within the limits of size of the product ANSVASME Bl.l6M-1984 AN AMERICAN NATIONAL STANDARD thread. At the functional diameter limit, using HI and LO thread gages, the standard practice is to have the gage tolerance within the limits of size of the product thread. Specif
28、ications for gage limits are listed in Tables 4 and 5. 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 Table 7, represent the highest commercial grade of accuracy and workman- ship an
29、d are specified for thread-setting gages; (6) X tolerances, shown in Table 6, are larger than W tolerances and are used for product inspection gages. Unless otherwise specified, all thread gages and gaging contacts that directly check the product thread shall be X tolerance. 3.6 Tolerance on Lead Cu
30、mulative effect of progressive or erratic helix variation and thick or thin end thread variations is specified as an allowable variation between any two threads not farther apart than the length of the standard taperlock or trilock gage, shown in ANSI/ ASME B47.laM. In the case of setting plugs, the
31、 specified tolerance shall be applicable to the thread length in the mating ring gage or nine pitches, whichever is smaller. For setting rings, the tolerance applies to a thread length of three pitches. The tolerance on lead establishes the width of a zone, measured parallel to the axis of the threa
32、d, within which the actual helical path must lie for the specified length of the thread. Measurements will be taken from a fixed referenck point located at the start of the first full thread to a sufficient number of positions along the entire helix to detect all types of lead variations. The amount
33、s that these positions vary from their basic (theoretical) positions will be recorded with due respect to sign. The greatest variation in each direction plus and minus (+)I will be selected and the sum of their values, disregarding sign, shall not exceed the specified tolerance. If the variations ar
34、e all in one direction, the maximum value governs conformance. In the case of truncated setting plugs, the lead variations present on the full- form portion and the truncated portion of an individual more than the length 11 gage shall not differ from each other by 0.003 mm over any portion equivalen
35、t to of the thread ring gage, or nine pitches, ANSVASME Bl.l6M-1984 AN AMERICAN NATIONAL STANDARD whichever is less. (When linear lead and drunkenness are measured as individual elements and the sum of these does not exceed the tolerance specified, the gage is well within tolerance.) 3.7 Tolerances
36、on Half-Angle Tolerances are specified for the half-angles rather than the included angle to assure that the bisector of the included angle will be perpendicular to the axis of the thread within proper limits. The equivalent of the variation from the true thread form caused by such irregularities as
37、 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 Product Thread When this check is specified, there are two general methods available for the in
38、spection procedures involved. (a) Direct Measurement of Lead and Half-Angle of Flanks. The lead and flank angles of the product thread may be measured by means of available measuring equipment, such as, but not limited to, thread indicating gages, projection comparators, measuring microscopes, gradu
39、ated cone points, lead measuring machines, helix variation measuring machines, and thread flank charting equipment. Diameter equivalents of such variations from nomi- nal may be calculated: each 0.0025 mm variation in lead amounts to 0.0043 mm (1.732 X 0.0025) increase in functional pitch diameter o
40、n external threads or a decrease in functional pitch diameter on internal threads for 60 deg. screw threads. The tangent of half-angle variation times 1.5 equals the approxi- mate maximum change in functional pitch diameter, based on a height of thread engagement of 0.625H and equal half-angle varia
41、tions. (6) Differential Gaging Utilizing Indicating Thread Gages. See Sections 4 and 5 for explanation and illustration 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
42、, and indicating gages, Z tolerance plain gages, and measuring instru- GAGES AND GAGING FOR METRIC M SCREW THREADS ments are given in Table 14 for external product threads, in Table i5 for internal product threads, and in Table 16 for setting gages. See Appendix A for methods of calibrating and insp
43、ecting gages. 4 TYPES OF GAGES FOR PRODUCT INTERNAL THREAD 4.1 GO Working Thread Plug Gages (Table 2 - Gage 1 .l) 4.1 .l Purpose and Use. The GO thread plug gage inspects the maximum-material GO functional limit, A, of product internal thread. The GO thread gage represents the maximum-material GO fu
44、nc- tional limit of the product internal thread, and its purpose is to assure interchangeable assembly of maximum-material mating parts. GO thread plug gages must enter and pass through the full-threaded length of the product freely. The GO thread plug gage is a cumulative check of all thread elemen
45、ts except the minor diameter. 4.1.2 Basic Design. The maximum-material limit on GO thread plug gages is made to the prescribed maximum-material limit of the product internal thread, and the gaging length is equal to the length of the gaging plug. 4.1.3 Gage Blanks. For practical and economic reasons
46、, the design and lengths of the gaging plug members have been standardized for various size ranges and pitches (see ANSI/ASME B47.laM or Table Cl). 4.1.4 Thread Form. The specifications for thread form are summarized in Table 4 and Fig. 1. 4.1.5 Thread Crests. The major diameter of the GO thread plu
47、g gage 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. 4.1.6 Thread Roots. The minor diameter of the GO thread plug gage shall be cleared beyond a p/8 width of fla
48、t either by an extension of the sides of the thread toward a sharp vee or by an undercut no 12 GAGES AND GAGING FOR ANSVASME Bl.l6M-1984 METRIC M SCREW THREADS AN AMERICAN NATIONAL STANDARD FIG. 1 MAXIMUM-MATERIAL GO FUNCTIONAL LIMIT greater thanp/8 maximum width and approximately central. 4.1.7 Run
49、out of Pitch and Major Cylinders. On thread plug gages an eccentric condition produces an oversize effective major diameter having a width of flat less than p/8, which may encroach on the minimum permissible limit for the root profile of the product internal thread. The permissible maximum effective major diameter, as determined by adding measurement of runout (full-indicator movement) with respect to the pitch cylinder to the measured major diameter, shall not exceed the maximum major diameter specified. 4.1
