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1、BS 969:2008 Specification for limits and tolerances on plain limit gauges ICS 17.040.10 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BRITISH STANDARD Licensed Copy: London South Bank University, South Bank University, 31/01/2009 03:43, Uncontrolled Copy, (c) BSI Publishing
2、and copyright information The BSI copyright notice displayed in this document indicates when the document was last issued. BSI 2008 ISBN 978 0 580 61998 4 The following BSI references relate to the work on this standard: Committee reference TDW/4 Draft for comment 08/30177723 DC Publication history
3、First published August 1941 First revision, May 1953 Second revision, May 1982 Third revision, November 2008 Amendments issued since publication Amd. no.DateText affected BS 969:2008 Licensed Copy: London South Bank University, South Bank University, 31/01/2009 03:43, Uncontrolled Copy, (c) BSI BSI
4、2008i BS 969:2008 Contents Foreword ii 1 Scope 1 2 Terms and definitions 1 3 Gauge limits and tolerances 2 4 Hardness 2 5 Marking 2 6 Gauges in disagreement 3 Annexes Annex A (informative) Examples of the use of Table 1 5 Annex B (informative) Principles of inspection using plain limit gauges 6 Anne
5、x C (informative) Values for gauges in imperial units 10 Bibliography 12 List of figures Figure 1 Relationships of workpiece and gauge tolerance zones 4 Figure A.1 Limits for hole 5 Figure A.2 Limits for shaft 6 Figure B.1 Possible extreme errors of form allowed by the effects of the limits of workp
6、iece size: holes 8 Figure B.2 Possible extreme errors of form allowed by the effects of the limits of workpiece size: shafts 9 List of tables Table 1 Gauge size limits at 20 C for ranges of workpiece tolerance 3 Table 2 Minimum gauge tolerance appropriate to type and size of gauge 4 Table C.1 Gauge
7、size limits at 20 C for ranges of workpiece tolerance in imperial units 10 Table C.2 Minimum gauge tolerance appropriate to type and size of gauge (imperial units) 11 Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 12, an inside back cover an
8、d a back cover. Licensed Copy: London South Bank University, South Bank University, 31/01/2009 03:43, Uncontrolled Copy, (c) BSI BS 969:2008 ii BSI 2008 Foreword This British Standard is published by BSI and came into effect on 3 2008. It was prepared by Technical Committee TDW/4, Technical product
9、realization. Supersession BS 969:2008 supersedes BS 929:1982, which is withdrawn. Information about this document This British Standard has been fully revised to bring it up to date. Presentational conventions The provisions of this standard are presented in roman (i.e. upright) type. Its requiremen
10、ts are expressed in sentences in which the principal auxiliary verb is “shall”. Commentary, explanation and general informative material is presented in notes in smaller italic type, and does not constitute a normative element. This publication does not purport to include all the necessary provision
11、s of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations. 0 November Licensed Copy: London South Bank University, South Bank University, 31/01/2009 03:43, Uncontrolled Copy, (c) BSI BSI 20081 BS 969:2008 1 Sc
12、ope This British Standard specifies tolerances and limits for simple forms of limit gauges, such as cylindrical plain plug, ring and gap gauges, for which gauge limits have not been stipulated. It specifies gauge tolerances for workpiece tolerances in the range between 0.009 mm and 3.200 mm and how
13、gauge limits are related to the workpiece limits. It also specifies types of gauge according to size and minimum workpiece tolerance. NOTEWhere a workpiece tolerance is outside the range 0.009 mm to 3.200 mm, or if it is not possible to conform to Table 2 regarding type of gauge, gauge tolerance and
14、 workpiece size, direct measurement should be used. The gauge tolerances specified are such that the size of any workpiece accepted by a gauge lies within the boundaries constituted by the workpiece limits. Furthermore, the magnitude of the gauge tolerances is consequent upon the amount of the workp
15、iece tolerance only. A wear allowance is provided on all GO gauges, i.e. those that control the maximum material condition of the workpiece. 2 Terms and definitions For the purposes of this British Standard the following terms and definitions apply. 2.1maximum material limit of size dimension defini
16、ng the maximum material condition of a feature at the maximum limit of size for an external feature and at the minimum limit of size for an internal feature NOTEA shaft is an example of an external feature and a hole is an example of an internal feature. 2.2least material limit of size dimension def
17、ining the minimum limit of local size for an external feature or maximum limit of local size for an internal feature NOTE A shaft is an example of an external feature and a hole is an example of an internal feature. 2.3GO gauge gauge that controls the maximum material limit of size of the workpiece
18、2.4NOT GO gauge gauge that controls the least material limit of size of the workpiece 2.5workpiece tolerance difference between the high and low limits of size of the workpiece Licensed Copy: London South Bank University, South Bank University, 31/01/2009 03:43, Uncontrolled Copy, (c) BSI BS 969:200
19、8 2 BSI 2008 3 Gauge limits and tolerances 3.1Gauge limits Where workpiece limits only are supplied to the gauges manufacturer (i.e. the purchaser does not state the required gauge limits), gauge limits for workpiece tolerances shall be as specified in Table 1 (Annex A gives examples of the applicat
20、ion of Table 1. Annex C gives the gauge size limits in imperial units). NOTEIt will be seen that gauge tolerance increases with workpiece tolerance only. To appreciate this apparent disregard of workpiece size, it should be remembered that the size factor plays its proper part when the workpiece tol
21、erance is fixed initially. 3.2Tolerances on gauge types The minimum tolerance on gauges shall be as specified in Table 2 (Annex C gives the minimum gauge tolerances in imperial units). NOTE 1In most cases it is uneconomical to manufacture, and impractical to use, limit gauges with tolerances on size
22、s smaller than those specified in Table 2. NOTE 2The GO gauges should be of full form and the NOT GO gauges should be designed to make contact at only the two ends of a diameter. The principle and reservations are described in Annex B. NOTE 3Recommended gauge designs are given in BS 1044-1. 4 Hardne
23、ss The hardness of the gauging surface shall be not less than 700 HV (600 HRC). NOTEIt is recommended that plain plug gauges of less than 6 mm nominal diameter should be suitably tempered on the relieved section to avoid breakage in use. 5 Marking 5.1 Gauges shall be marked with: a)the limiting size
24、 of the workpiece which the gauge controls; b)GO or NOT GO, as appropriate. 5.2 Gauges can also be marked with: a)the manufacturers name or trade mark; b)a serial number. Licensed Copy: London South Bank University, South Bank University, 31/01/2009 03:43, Uncontrolled Copy, (c) BSI BSI 20083 BS 969
25、:2008 6 Gauges in disagreement It is possible that similar satisfactory gauges, using a different region of the permitted gauge tolerance, may respectively accept and reject a workpiece. Such cases are likely to be rare and a dispute can be resolved by measuring the workpiece directly. Table 1Gauge
26、size limits at 20 C for ranges of workpiece tolerance (see Figure 1) 1234567 Workpiece toleranceA)Tolerance, T, for GO and for NOT GO gauges Wear allowance, W, for GO gauges only Plug type gaugesB)Ring or gap gaugesC), D) GO NOT GOGO NOT GO mm mm mm mm mm mm mm 0.009D) u 0.018 0.001 0.001LHpHp p L+
27、0.018 u 0.032 0.002 0.001LHpHp p L+ 0.032 u 0.058 0.003 0.002LHpHp p L+ 0.058 u 0.100 0.004 0.004LHpHp p L+ 0.100 u 0.180 0.006 0.007LHpHp p L+ 0.180 u 0.320 0.009 0.012LHpHp p L+ 0.320 u 0.580 0.014 0.025LHpHp p L+ 0.580 u 1.000 0.025 0.048LHpHp p L+ 1.000 u 1.800 0.040 0.080LHpHp p L+ 1.800 u 3.20
28、0 0.050 0.155LHpHp p L+ NOTE Gauge wear and wear allowance. Provision is made for the wear of GO gauges by the introduction of a wear allowance (W) between the tolerance zone for the gauge and the maximum material limit for the workpiece. Wear allowance is not applied to the NOT GO gauge. Gauge user
29、s have to watch for the effect of wear upon sizes of their gauges. Regular examination and measurement of gauges in use is essential so that a gauge, particularly a GO gauge which has worn outside its limit, is detected and withdrawn from service to avoid accepting workpieces exceeding the maximum m
30、aterial limit. A) Difference between high (H) limit and low (L) limit shaft or hole. B) Limits expressed with respect to H minus L for the workpiece (hole). Errors of size and form of the gauge are to be contained within these limits. C) Limits expressed with respect to H minus L for the workpiece (
31、shaft). Errors of size and form of the gauge are to be contained within these limits. D) A workpiece with a tolerance less than 0.009 mm should be measured directly, or by means other than the gauges described in this standard. + + 0.002 0.001 0 0.001 0.001 0.002 0.001 0 + + 0.003 0.001 0 0.002 0.00
32、1 0.003 0.002 0 + + 0.005 0.002 0 0.003 0.002 0.005 0.003 0 + + 0.008 0.004 0 0.004 0.004 0.008 0.004 0 + + 0.013 0.007 0 0.006 0.007 0.013 0.006 0 + + 0.021 0.012 0 0.009 0.012 0.021 0.009 0 + + 0.039 0.025 0 0.014 0.025 0.039 0.014 0 + + 0.073 0.048 0 0.025 0.048 0.073 0.025 0 + + 0.120 0.080 0 0.
33、040 0.080 0.120 0.040 0 + + 0.205 0.155 0 0.050 0.155 0.205 0.050 0 Licensed Copy: London South Bank University, South Bank University, 31/01/2009 03:43, Uncontrolled Copy, (c) BSI BS 969:2008 4 BSI 2008 Figure 1Relationships of workpiece and gauge tolerance zones Table 2Minimum gauge tolerance appr
34、opriate to type and size of gauge Gauge size Type Minimum tolerance appropriate to the type and size of gauge AboveUp to and including mm mm Cylindrical plug mm 25 0.001 25 50 0.002 50 100 0.003 100 150 0.006 150 200 0.009 100 250 Cylindrically ended bar 0.009 250 500 0.016 375750Spherically ended r
35、od and pin gauges 0.016 7501 0000.030 13 Ring and gap gauges 0.001 13 25 0.002 25 50 0.003 50 75 0.006 75 175 0.009 175 400 0.016 400 750 0.030 Hole Low limit for hole (L) High limit for hole (H) High limit for shaft (H) Tolerance for hole Workpieces T T Plug gauges Not go gauge Go gauge Direction o
36、f wear of gauge Direction of wear of gauge W Shaft Low limit for shaft (L) Tolerance for shaft T T Gap and ring gauges Go gauge Not go gauge W Gauges Licensed Copy: London South Bank University, South Bank University, 31/01/2009 03:43, Uncontrolled Copy, (c) BSI BSI 20085 BS 969:2008 Annex A (inform
37、ative)Examples of the use of Table 1 A.1Example 1: Limits for hole The limits for GO and NOT GO gauges for an internal diameter (hole) (see Figure A.1) are found as follows. The workpiece tolerance is 0.200 mm. a) From column 4 of Table 1, the limits for the GO gauge are: + 0.021 mm + 0.012 mm There
38、fore, the size of the GO gauge is: b) From column 5 of Table 1, the limits for the NOT GO gauge are: 0 mm p0.009 mm. Therefore, the size of the NOT GO gauge is: Hp A.2Example 2: Limits for shaft The limits for GO and NOT GO gauges for a shaft (see Figure A.2) are found as follows. The workpiece tole
39、rance is 0.040 mm. a) From column 6 of Table 1, the limits for the GO gauge are: p0.002 mm p0.005 mm Therefore, the size of the GO gauge is: b) From column 7 of Table 1, the limits for the NOT GO gauge are: + 0.003 mm 0 Therefore, the size of the NOT GO gauge is: L + L+ + 0.021 0.012 75.021 75.012 =
40、 0 0.009 75.200 75.191 = Figure A.1Limits for hole Key 1 Workpiece 1 75.2 mm (H) 75 mm (L) H 0 0 .002 005 44.928 44.925 = 0.003 0 44.893 44.890 = Licensed Copy: London South Bank University, South Bank University, 31/01/2009 03:43, Uncontrolled Copy, (c) BSI BS 969:2008 6 BSI 2008 Annex B (informati
41、ve)Principles of inspection using plain limit gauges B.1Limits The workpiece limits of size within the prescribed length of assembly are considered to be as follows. a)Holes. The diameter of a perfect cylinder just contacting the high points of the workpiece is to be not less than the workpiece lowe
42、r limit. The maximum diameter at any position in the hole does not exceed the workpiece upper limit. b)Shafts. The diameter of a perfect cylinder just circumscribing the shaft is to be not more than the workpiece upper limit. The minimum diameter at any position on the shaft is to be not less than t
43、he workpiece lower limit. These considerations mean that if the workpiece is everywhere at its maximum material limit, it should be perfectly round and straight. Unless specific tolerances on circularity of section and straightness are specified, departures of the workpiece from cylindrical form can
44、 reach the diametral tolerance only if the workpiece size is at the least material limit. Examples of extreme errors in form are shown in Figure B.1 and Figure B.2. B.2Application of limit gauges to workpieces NOTEThe relationship of the limits for gauges to the workpiece limits is given in Figure 1
45、. B.2.1 The maximum material limit of a workpiece, i.e. the upper limit for a shaft or the lower limit for a hole, should be checked with a full form GO gauge that should be of the same length as the intended assembly of workpieces, shafts and holes concerned. The workpiece has to pass into or over
46、the gauge. B.2.2 The least material limit of a workpiece, i.e. the lower limit for a shaft or the upper limit for a hole, should be checked with a NOT GO gauge designed to contact the workpiece at two diametrically opposite points. The workpiece is not to pass into or over the gauge at any diametral
47、 position around and along the workpiece length. Figure A.2Limits for shaft Key 1 Workpiece 1 44.93 mm (H) 44.89 mm (L) Licensed Copy: London South Bank University, South Bank University, 31/01/2009 03:43, Uncontrolled Copy, (c) BSI BSI 20087 BS 969:2008 B.2.3 The system of checking described in B.2
48、.1 and B.2.2 is known as the Taylor Principle. For practical reasons the following departures from the strict application of the Taylor Principle are recognized. a)Gauging at the maximum material limit 1)The length of a GO cylindrical plug or ring gauge may be less than the length of engagement of t
49、he mating workpieces if it is known that, with the manufacturing process used, the error of straightness of the hole or shaft is so small that it does not affect the character of fit of the assembled workpieces. This departure from the ideal facilitates the use of standard gauge blanks. 2)A GO cylindrical plug gauge might be too heavy for gauging a large hole. It is permissible to use instead a segmental cylindrical bar or spherical gauge if it is known that with the manufacturing process used, the error of roundness
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