1、BRITISH STANDARD BS 4377:1991 Incorporating Amendment No. 1 Specification for Tapping of holes to receive wire thread inserts (ISO metric threads)BS4377:1991 This British Standard, having been prepared under the directionof the General Mechanical Engineering Standards Policy Committee, waspublished
2、under the authorityof the Standards Boardand comes into effect on 31 May1991 BSI 04-1999 First published December1968 Second edition April1980 Third edition May1991 The following BSI references relate to the work on this standard: Committee reference GME/9 Draft for comment 90/70426 DC ISBN 0 580 19
3、425 6 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the General Mechanical Engineering Standards Policy Committee (GME/-) to Technical Committee GME/9, upon which the following bodies were represented: BEAMA Ltd. British Constructional Ste
4、elwork Association Ltd. British Industrial Fasteners Federation British Railways Board British Steel Industry British Steel Industry (Wire Section) Gauge and Tool Makers Association Ministry of Defence Society of Motor Manufacturers and Traders Limited Washer Manufacturers Association of Great Brita
5、in The following bodies were also represented in the drafting of the standard, through subcommittees and panels: Defence Manufacturers Association General Municipal Boilermaker and Allied Trades Union Screw Thread Tool Manufacturers Association Society of British Aerospace Companies Limited Amendmen
6、ts issued since publication Amd. No. Date Comments 7824 September 1993 Indicated by a sideline in the marginBS4377:1991 BSI 04-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Form of thread and limits of size for tapped holes 1 3 Screwing taps 5 4 Gauging syste
7、m 10 5 Marking 12 Figure 1 Basic form of ISO metric assembly 2 Figure 2 Screwing taps (d = over0.9mm to2.8mm) 7 Figure 3 Screwing taps (d = over2.8mm to10mm) 7 Figure 4 Screwing tape (d = over10mm) 7 Figure 5 Relationship of tap tolerance to insert tapped hole tolerance 9 Table 1 Limits and toleranc
8、es for tapped holes for inserts: ISO metric threads, class 5H 3 Table 2 Limits and tolerances for tapped holes for inserts: ISO metric threads, class 6H 4 Table 3 General dimensions of screwing taps for insert tapped holes (metric series) 6 Table 4 Tolerances on dimensions of shanks and squares of t
9、aps for insert tapped holes 8 Table 5 Tolerances on dimensions of overall length and length of thread of taps for insert tapped holes 8 Table 6 Tolerances on pitch of taps for insert tapped holes 8 Table 7 Limits of size for ISO metric taps for insert tapped holes 9 Table 8 Flank angle tolerances fo
10、r gauges 11 Table 9 Pitch tolerances for gauges 11 Table 10 Internal product thread: deviations for simple pitch diameters of GO and NOT GO screw plug gauges 11 Table 11 Deviations for major diameters of GO and NOT GO screw plug gauges 11 Table 12 Internal product thread: deviations for GO and NOT G
11、O plain plug gauges 12 Table 13 Limits of size for GO gauges for ISO metric insert tapped holes (all classes) 12 Table 14 Limits of size for NOT GO gauges for insert tapped holes suitable for class5H ISO metric threads 14 Table 15 Limits of size for NOT GO gauges for insert tapped holes suitable for
12、 class6H ISO metric threads 15 Publications referred to Inside back coverBS4377:1991 ii BSI 04-1999 Foreword This British Standard has been prepared under the direction of the General Mechanical Engineering Standards Policy Committee. It is a revision of BS4377:1980 which is withdrawn. It differs fr
13、om the 1980 edition in the following respects. a) Amendments have been made to certain tap features that are already included in BS949-1, together with new tap pitch diameter formulae and values. These changes do not affect interchangeability with existing stocks of taps produced to BS4377:1980. b)
14、This edition now includes the following spark plug designations. M14 1.25 M10 1 c) Details have been included of the following additional sizes. M1.6 0.35 M2.2 0.45 M12 1.5 M12 1 A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are
15、 responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to16, an inside back cover and a back cover. This standard has
16、 been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on theinside front cover.BS4377:1991 BSI 04-1999 1 1 Scope This British Standard specifies requirements for: a) limits of size for tapped holes to accommodate wire thread insert
17、s which provide ISO metric thread sizes from M1.6 (1.6mm diameter) to M39 (39mm diameter) inclusive; b) screwing taps intended to produce holes to the limits of size specified; c) a gauging system for checking the tapped holes. NOTEThe titles of the publications referred to in this standard are list
18、ed on the inside back cover. 2 Form of thread and limits of size for tapped holes 2.1 Holes shall be threaded to provide class5H or class6H limits in accordance with BS3643 when assembled with the wire thread inserts, and shall be of ISO metric form as illustrated inFigure 1. NOTEIt is recommended t
19、hat class5H limits be specified for use with prevailing torque type wire thread inserts. 2.2 Holes to provide class 5H limits for ISO metric thread sizes M1.6 to M39 inclusive shall be tapped to the limits specified inTable 1. 2.3 Holes to provide class 6H limits for ISO metric thread sizes M1.6 to
20、M39 inclusive shall be tapped to the limits specified inTable 2. NOTE 1The limits given inTable 1 andTable 2 are designed to permit the production, under normal conditions, of holes to suit the classes of threads stated. Under ideal conditions it may be possible to achieve a closer class of fit on t
21、he final installation than those indicated in the tables. NOTE 2In order to distinguish requirements for holes intended to receive inserts from those intended to receive threaded components, it is recommended that the former be clearly identified on drawings and specifications. This may be done by s
22、pecifying the actual major, pitch and minor diameters of the hole and their limits, or by the addition of the words “wire insert” and number of this British Standard to the designation of the thread. Example: “M5 0.8 5H, wire insert BS4377”BS 4377:1991 2 BSI 04-1999 Figure 1 Basic form of ISO metric
23、 assemblyBS4377:1991 BSI 04-1999 3 Table 1 Limits and tolerances for tapped holes for inserts: ISO metric threads, class5H a 1 2 3 4 5 6 7 8 Size designation Major diameter Pitch diameter Minor diameter Minimum Maximum Minimum Tolerance b Maximum Minimum Tolerance b mm mm mm mm mm mm mm M1.6 0.35 2.
24、055 1.860 1.827 0.033 1.756 1.676 0.080 M2 0.4 2.520 2.296 2.260 0.036 2.177 2.087 0.090 M2.2 0.45 2.785 2.532 2.492 0.040 2.397 2.297 0.100 M2.5 0.45 3.085 2.832 2.792 0.040 2.697 2.597 0.100 M3 0.5 3.650 3.367 3.325 0.042 3.220 3.108 0.112 M3.5 0.6 4.279 3.940 3.890 0.050 3.755 3.630 0.125 M4 0.7
25、4.909 4.509 4.455 0.054 4.292 4.152 0.140 M4.5 0.75 5.474 5.039 4.987 0.052 4.812 4.662 0.150 M5 0.8 6.039 5.577 5.520 0.057 5.333 5.173 0.160 M6 1 7.299 6.719 6.650 0.069 6.406 6.216 0.190 M7 1 8.299 7.719 7.650 0.069 7.406 7.216 0.190 M8 1.25 9.624 8.886 8.812 0.074 8.483 8.271 0.212 M8 1 9.299 8.
26、719 8.650 0.069 8.406 8.216 0.190 M10 1.5 11.949 11.061 10.974 0.087 10.561 10.325 0.236 M10 1.25 11.624 10.886 10.812 0.074 10.483 10.271 0.212 M10 1 11.299 10.724 10.650 0.074 10.406 10.216 0.190 M12 1.75 14.273 13.236 13.137 0.099 12.644 12.379 0.265 M12 1.5 13.949 13.067 12.974 0.093 12.561 12.3
27、25 0.236 M12 1.25 13.624 12.898 12.812 0.086 12.483 12.271 0.212 M12 1 13.299 12.724 12.650 0.074 12.406 12.216 0.190 M14 2 16.598 15.406 15.299 0.107 14.733 14.433 0.300 M14 1.5 15.949 15.067 14.974 0.093 14.561 14.325 0.236 M14 1.25 15.624 14.898 14.812 0.086 14.483 14.271 0.212 M16 2 18.598 17.40
28、6 17.299 0.107 16.733 16.433 0.300 M16 1.5 17.949 17.067 16.974 0.093 16.561 16.325 0.236 M18 2.5 21.248 19.738 19.624 0.114 18.896 18.541 0.355 M18 2 20.598 19.406 19.299 0.107 18.733 18.433 0.300 M18 1.5 19.949 19.067 18.974 0.093 18.561 18.325 0.236 M20 2.5 23.248 21.738 21.624 0.114 20.896 20.54
29、1 0.355 M20 2 22.598 21.406 21.299 0.107 20.733 20.433 0.300 M20 1.5 21.949 21.067 20.974 0.093 20.561 20.325 0.236 a See note 1 to2.3. b The tolerance column gives the difference between the maximum and minimum diameters: it does not give a tolerance on the diameters.BS4377:1991 4 BSI 04-1999 Table
30、 1 Limits and tolerances for tapped holes for inserts: ISO metric threads, class5H a Table 2 Limits and tolerances for tapped holes for inserts: ISO metric threads, class6H a 1 2 3 4 5 6 7 8 Size designation Major diameter Pitch diameter Minor diameter Minimum Maximum Minimum Tolerance b Maximum Min
31、imum Tolerance b mm mm mm mm mm mm mm M22 2.5 25.248 23.738 23.624 0.114 22.896 22.541 0.355 M22 2 24.598 23.406 23.299 0.107 22.733 22.433 0.300 M22 1.5 23.949 23.067 22.974 0.093 22.561 22.325 0.236 M24 3 27.897 26.093 25.949 0.144 25.050 24.650 0.400 M24 2 26.598 25.414 25.299 0.115 24.733 24.433
32、 0.300 M27 3 30.897 29.093 28.949 0.144 28.050 27.650 0.400 M30 3.5 34.547 32.428 32.273 0.155 31.208 30.758 0.450 M33 3.5 37.547 35.428 35.273 0.155 34.208 33.758 0.450 M36 4 41.196 38.763 38.598 0.165 37.341 36.866 0.475 M39 4 44.196 41.763 41.598 0.165 40.341 39.866 0.475 a See note 1 to2.3. b Th
33、e tolerance column gives the difference between the maximum and minimum diameters: it does not give a tolerance on the diameters. 1 2 3 4 5 6 7 8 Size designation Major diameter Pitch diameter Minor diameter Minimum Maximum Minimum Tolerance, t bc Maximum Minimum Tolerance b mm mm mm mm mm mm mm M1.
34、6 0.35 2.055 1.874 1.827 0.047 1.756 1.676 0.080 M2 0.4 2.520 2.311 2.260 0.051 2.177 2.087 0.090 M2.2 0.45 2.785 2.547 2.492 0.055 2.397 2.297 0.100 M2.5 0.45 3.085 2.847 2.792 0.055 2.697 2.597 0.100 M3 0.5 3.650 3.384 3.325 0.059 3.220 3.108 0.112 M3.5 0.6 4.279 3.959 3.890 0.069 3.755 3.630 0.12
35、5 M4 0.7 4.909 4.529 4.455 0.074 4.292 4.152 0.140 M4.5 0.75 5.474 5.059 4.987 0.072 4.812 4.662 0.150 M5 0.8 6.039 5.597 5.520 0.077 5.333 5.173 0.160 M6 1 7.299 6.742 6.650 0.092 6.406 6.216 0.190 M7 1 8.299 7.742 7.650 0.092 7.406 7.216 0.190 M8 1.25 9.624 8.912 8.812 0.100 8.483 8.271 0.212 M8 1
36、 9.299 8.742 8.650 0.092 8.406 8.216 0.190 M10 1.5 11.949 11.089 10.974 0.115 10.561 10.325 0.236 M10 1.25 11.624 10.912 10.812 0.100 10.483 10.271 0.212 M10 1 11.299 10.742 10.650 0.092 10.406 10.216 0.190 a See note 1 to2.3. b The tolerance column gives the difference between the maximum and minim
37、um diameters: it does not give a tolerance on the diameters. c See3.4.BS4377:1991 BSI 04-1999 5 Table 2 Limits and tolerances for tapped holes for inserts: ISO metric threads, class6H a 3 Screwing taps 3.1 General dimensions 3.1.1 General dimensions of screwing taps for ISO metric threaded holes sha
38、ll be as given inTable 3 andFigure 2,Figure 3 andFigure 4. NOTEThese dimensions are in accordance with those specified for standard screwing taps in BS949 but are tabulated here for convenience because the general dimensions of taps are associated with the major diameters of the threads which differ
39、, in the case of the taps covered by the present standard, from the nominal major diameters. 1 2 3 4 5 6 7 8 Size designation Major diameter Pitch diameter Minor diameter Minimum Maximum Minimum Tolerance, t bc Maximum Minimum Tolerance b mm mm mm mm mm mm mm M12 1.75 14.273 13.271 13.137 0.134 12.6
40、44 12.379 0.265 M12 1.5 13.949 13.099 12.974 0.125 12.561 12.325 0.236 M12 1.25 13.624 12.926 12.812 0.114 12.483 12.271 0.212 M12 1 13.299 12.749 12.650 0.099 12.406 12.216 0.190 M14 2 16.598 15.444 15.299 0.145 14.733 14.433 0.300 M14 1.5 15.949 15.099 14.974 0.125 14.561 14.325 0.236 M14 1.25 15.
41、624 14.926 14.812 0.114 14.483 14.271 0.212 M16 2 18.598 17.444 17.299 0.145 16.733 16.433 0.300 M16 1.5 17.949 17.099 16.974 0.125 16.561 16.325 0.236 M18 2.5 21.248 19.778 19.624 0.154 18.896 18.541 0.355 M18 2 20.598 19.444 19.299 0.145 18.733 18.433 0.300 M18 1.5 19.949 19.099 18.974 0.125 18.56
42、1 18.325 0.236 M20 2.5 23.248 21.778 21.624 0.154 20.896 20.541 0.355 M20 2 22.598 21.444 21.299 0.145 20.733 20.433 0.300 M20 1.5 21.949 21.099 20.974 0.125 20.561 20.325 0.236 M22 2.5 25.248 23.778 23.624 0.154 22.896 22.541 0.355 M22 2 24.598 23.444 23.299 0.145 22.733 22.433 0.300 M22 1.5 23.949
43、 23.099 22.974 0.125 22.561 22.325 0.236 M24 3 27.897 26.135 25.949 0.186 25.050 24.650 0.400 M24 2 26.598 25.454 25.299 0.155 24.733 24.433 0.300 M27 3 30.897 29.135 28.949 0.186 28.050 27.650 0.400 M30 3.5 34.547 32.472 32.273 0.199 31.208 30.758 0.450 M33 3.5 37.547 35.472 35.273 0.199 34.208 33.
44、758 0.450 M36 4 41.196 38.809 38.598 0.211 37.341 36.866 0.475 M39 4 44.196 41.809 41.598 0.211 40.341 39.866 0.475 a See note 1 to2.3. b The tolerance column gives the difference between the maximum and minimum diameters: it does not give a tolerance on the diameters. c See3.4.BS4377:1991 6 BSI 04-
45、1999 Table 3 General dimensions of screwing taps for insert tapped holes (metric series) (seeFigure 2, Figure 3 andFigure 4) 1 2 3 4 5 6 7 8 9 Diameter Pitch, P Shank diameter d 1 Overall length, L Maximum thread length l 1Recess diameter, d 2 Length of neck and thread l 3 Square length, l 2 Across
46、flats, a Nominal Minimum major mm mm mm mm mm mm mm mm mm M1.6 2.075 0.35 2.50 41.0 8.0 13.5 4.0 2.00 M2 2.556 0.4 2.80 44.5 9.5 15.5 5.0 2.24 M2.2 2.825 0.45 3.15 48.0 11.0 2.36 18.0 5.0 2.50 M2.5 3.125 0.45 3.15 48.0 11.0 2.36 18.0 5.0 2.50 M3 3.692 0.5 4.00 53.0 13.0 2.80 21.0 6.0 3.15 M3.5 4.326
47、 0.6 4.50 53.0 13.0 3.15 21.0 6.0 3.55 M4 4.959 0.7 5.00 58.0 16.0 3.55 25.0 7.0 4.00 M4.5 5.526 0.75 5.60 62.0 17.0 4.00 26.0 7.0 4.50 M5 6.093 0.8 6.30 66.0 19.0 4.50 30.0 8.0 5.00 M6 7.359 1.0 8.00 72.0 22.0 6.00 35.0 9.0 6.30 M7 8.359 1.0 9.00 72.0 22.0 7.10 36.0 10.0 7.10 M8 9.690 1.25 10.00 80
48、.0 24.0 7.50 39.0 11.0 8.00 M8 9.359 1.0 10.00 80.0 24.0 7.50 39.0 11.0 8.00 M10 12.021 1.5 9.00 89.0 29.0 10.0 7.10 M10 11.690 1.25 9.00 89.0 29.0 10.0 7.10 M10 11.359 1.0 9.00 89.0 29.0 10.0 7.10 M12 14.352 1.75 11.20 95.0 30.0 12.0 9.00 M12 14.021 1.5 11.20 95.0 30.0 12.0 9.00 M12 13.690 1.25 11.
49、20 95.0 30.0 12.0 9.00 M12 13.359 1.0 11.20 95.0 30.0 12.0 9.00 M14 16.682 2.0 12.50 102.0 32.0 13.0 10.00 M14 16.021 1.5 12.50 102.0 32.0 13.0 10.00 M14 15.690 1.25 12.50 102.0 32.0 13.0 10.00 M16 18.682 2.0 14.00 112.0 37.0 14.0 11.20 M16 18.021 1.5 14.00 112.0 37.0 14.0 11.20 M18 21.342 2.5 16.00 118.0 38.0 16.0 12.50 M18 20.682 2.0 14.00 112.0 37.0 14.0 11.20 M18 20.021 1.5
