1、BRITISH STANDARD BS 2518-1: 1954 Incorporating Amendment Nos. 1 and 2 Specification for Rotary form-relieved gear cutters Part 1: Diametral pitchBS2518-1:1954 This British Standard, having been approved by the MechanicalEngineering IndustryStandards Committee and endorsed by the Chairman ofthe Engin
2、eering Divisional Council, was published under theauthority of the General Council on 9 November 1954 BSI 01-2000 The following BSI references relate to the work on this standard: Committee reference MEE/127 Draft for comment CT(MEE) 2228 ISBN 0 580 34124 0 Co-operating organizations The Mechanical
3、Engineering Industry Standards Committee, under whose supervision this British Standard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: The Government departments and scientific and industrial organizations marked with
4、an asterisk in the above list, together with the following scientific and industrial organizations, were directly represented on the committee entrusted with the preparation of this standard: Admiralty High Commission of India Air Ministry Institute of Marine Engineers Associated Offices Technical C
5、ommittee Institute of Petroleum Association of Consulting Engineers Institution of Civil Engineers (Incorporated) Institution of Gas Engineers British Chemical Plant Manufacturers Institution of Heating and Ventilating Association Engineers British Compressed Air Society Institution of Mechanical En
6、gineers British Electrical and Allied Manufacturers Institution of Mechanical Engineers Association* (Automobile Division) British Electricity Authority and Area Boards Institution of Production Engineers* British Engineers Association Locomotive Manufacturers Association British Internal Combustion
7、 Engine Machine Tool Trades Association* Manufacturers Association Ministry of Fuel and Power British Iron and Steel Federation Ministry of Labour and National Service British Railways, The British Transport (Factory Department) Commission Ministry of Supply* Crown Agents for Oversea Governments and
8、 Ministry of Transport Administrations Ministry of Works D.S.I.R. Mechanical Engineering Research National Physical Laboratory Laboratory* Radio Industry Council Engineering Equipment Users Association War Office Gas Council British Gear Manufacturers Association Parsons Marine Engineering Turbine M
9、illing Cutter and Reamer Trade Association Research and Development Association North East Coast Institution of Engineers and Shipbuilders Society of Motor Manufacturers and Traders Ltd. Amendments issued since publication Amd. No. Date of issue Comments 2154 April1955 2290 June1977 Indicated by a s
10、ideline in the marginBS2518-1:1954 BSI 01-2000 i Contents Page Co-operating organizations Inside front cover Foreword iii 1 Scope 1 2 Definitions 1 3 Gear tooth form 1 4 Cutter groups 3 5 Cutter dimensions 7 6 Cutter keyways 7 7 Arbors and keys 7 8 Marking 7 Appendix A Milled gears intended to mesh
11、with generated gears 11 Appendix B Form relief 11 Appendix C Recommended arbors and keys for standard cutters 11 Appendix D Marking of cutters 12 Appendix E Ordering instructions 12 Appendix F Rotary gear cutters with14“ pressure angle 13 Appendix G 23 Appendix H Metric sizes for rotary form-relieve
12、d gear cutters 24 Figure 1 Rotary form-relieved gear cutter 2 Figure 2 20 composite basic rack tooth profile for unit normal diametral pitch 4 Figure 3 Cutters Nos. 1to 8 P.A. 20 Table 2 5 Figure 4 14“ composite (A.G.M.A. Standard) basic rack tooth profile for unit normal diametral pitch 14 Figure 5
13、 Cutters Nos. 1, 1“, 2, 2“ and 3 P.A. 14“ Table 9 Appendix F 15 Figure 6 Cutters Nos. 3“ and 4 P.A. 14“ Table 10 Appendix F 17 Figure 7 Cutters Nos. 4“, 5, 5“, 6and 6“ P.A. 14“ Table 11 Appendix F 19 Figure 8 Cutters Nos. 7, 7“ and 8 P.A. 14“ Table 12 Appendix F 21 Table 1A Standard cutter group (8C
14、utters) 3 Table 1B Special cutter group (15Cutters) 3 Table 2 Profile dimensions for 1D.P. 20 P.A. rotary gear cutters 6 Table 3 Limits of tolerances on standard chordal tooth thickness “CT” 6 Table 4 Cutter diameters and bores 8 Table 5A Widths of standard20 pressure angle cutters 9 Table 5B Limits
15、 of tolerance on width 9 Table 6 Keyways 10 Table 7 Reduction of tooth thickness of milled gear teeth for cutters of1D.P. 11 Table 8A Diameters of arbors 11 Table 8B Keys for arbors 12 Table 9 Profile dimensions for 1D.P. 14“ P.A. rotary gear cutters,cutternumbers 1, 1“, 2, 2“, 3 16 Table 10 Profile
16、 dimensions for 1D.P. 14“ P.A. rotary gear cutters,cutternumbers 3“, 4 18 Table 11 Profile dimensions for 1D.P. 14“ P.A. rotary gear cutters,cutternumbers 4“, 5, 5“, 6, 6“ 20BS2518-1:1954 ii BSI 01-2000 Page Table 12 Profile dimensions for 1D.P. 14“ P.A. rotary gear cutters,cutternumbers 7, 7“, 8 22
17、 Table 13 Equivalent pitches 23 Table 14 Diameters and bores 24 Table 15 Cutter keyways 25 Table 16 Diameters of arbors 25 Table 17 Keys for arbors 26BS2518-1:1954 BSI 01-2000 iii Foreword This standard makes reference to the following British Standards: BS 2519, Glossary of terms and notation for t
18、oothed gearing. BS 436:1940, Machine cut gears. A. Helical and straight spur. This British Standard was prepared under the authority of the Mechanical Engineering Industry Standards Committee and forms part of a series of standards for gear-forming tools, of which the following have been published:
19、BS 2007:1953, Circular gear shaving cutters: Accuracy. BS 2062:1953, Gear hobs. Others in the series will relate to pinion type gear cutters and rack type gear cutters. This British Standard supersedes the tables relating to rotary form-relieved gear cutters included in BS 122:1938, “Milling cutters
20、 and reamers”. As a result of experience gained from the use of these tables, it became clear that the information they provide is insufficient to ensure uniformity in the manufacture of such cutters; and the amendments and recommendations referred to below have therefore been introduced in the pres
21、ent standard: a) The British Standard pressure angle of20 has been adopted since it leads to a well balanced compromise between strength, resistance to wear and quietness of running in gears. The composite basic rack tooth profile adopted (Figure 2) is designed to avoid undercutting in gears having
22、a small number of teeth, and it provides also suitable tip relief in the teeth cut. b) An odontograph diagram with table of dimensions for1D.P. cutters is provided for the setting out of the correct profiles of the full range of cutters used in rotary gear cutter practice for gears from a12 tooth pi
23、nion to a rack. Values for cutter addendum and tooth thickness have been added to these tables. c) A table giving limits of tolerances on standard tooth thickness has also been included. NOTEAn auxiliary table in Appendix A shows the amount of reduction necessary in chordal gear tooth thickness to e
24、nable a milled gear to mesh with a standard generated gear. d) Amendments have been made to the sizes of bores and diameters. Tables of metric bores, diameters, keys and keyways have been provided in Appendix H. e) A table of tolerances on the overall width of cutters has been included and the nomin
25、al widths have been altered in some cases. f) It is recommended that the preferred pitches, cutter diameters and cutter bore diameters listed in the tables should be adopted wherever practicable. The bracketed sizes should be avoided wherever possible. g) “Diametral pitch” has been used throughout t
26、his standard to define pitch; and it is recommended that this practice be adopted exclusively when referring to rotary gear cutters. The equivalents in circular pitch and metric module of diametral pitches are given in Appendix G for reference. 14“ pressure angle cutters. As14“ pressure angle gears
27、are still in fairly general demand for replacement and other purposes, Appendix F and Table 9, Table 10, Table 11, Table 12 have been added to this standard in order to ensure uniformity in the manufacture of such cutters.BS2518-1:1954 iv BSI 01-2000 Recommended ordering instructions, to be supplied
28、 by a purchaser, are given in Appendix E. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations.
29、 Summary of pages This document comprises a front cover, an inside front cover, pages i to iv, pages1to 26, an inside back coverand a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside
30、front cover.BS2518-1:1954 BSI 01-2000 1 1 Scope This British Standard applies to rotary form-relieved cutters for milling spur and helical gears within the range1to30diametral pitch. Such cutters are deemed satisfactory for cutting gears intended to mesh together under conditions of service which ar
31、e not severe. NOTEIt is not recommended that cutters designed in accordance with this standard be used for milling gears intended to mesh with generated gears. Where, however, it is found necessary to use milled gears for this purpose, a reduction in chordal thickness of the gear teeth is essential.
32、 (See Appendix A). 2 Definitions a rotary form-relieved gear cutter a circular milling cutter having on its periphery teeth of such form that it will cut out a single tooth space in a gear form relief the provision of a cutting clearance between the cutter teeth and the work (See Figure 1 and Append
33、ix B.) chordal tooth thickness (CT) of a cutter the thickness measured at a distance (CA) from the top of the tooth based on the basic rack profile dedendum the terms used in describing parts of rotary form-relieved cutters are illustrated in Figure 1. General terms relating to gears are given in BS
34、2519 “Glossary of terms and notation for toothed gearing” 3 Gear tooth form Cutters shall be designed to cut gears corresponding to the20 composite basic rack tooth profile shown in Figure 2.BS 2518-1:1954 2 BSI 01-2000 Figure 1 Rotary form-relieved gear cutterBS2518-1:1954 BSI 01-2000 3 4 Cutter gr
35、oups a) Standard cutter groups. In accordance with rotary gear cutter practice, the standard group for any given pitch shall consist of eight cutters, numbered1to8inclusive, for milling gears having the numbers of teeth specified in the following table: Table 1A Standard cutter group(8Cutters) It sh
36、ould be noted that the form of tooth obtained with any cutter is strictly correct only when the number of teeth of the gear is the smallest specified for the cutter. b) Special cutter group. It is sometimes necessary to obtain a closer approximation to the correct tooth form for gears with intermedi
37、ate numbers of teeth. To meet this requirement, intermediate (half size) values of cutters as given in Table 1B may be provided to sub-divide the standard group. Table 1B Special cutter group(15Cutters) In this case also the tooth form obtained is strictly correct only for gears with the smallest nu
38、mber of teeth specified. NOTEFor helical gears, the virtual number of teeth, calculated as “t sec 2B” should be used to select a cutter number, “t” being the actual number of teeth and “B” the helix angle of the gear. c) An odontograph diagram (Figure 3) for standard20 pressure angle cutters is appe
39、nded to Table 2 to enable the profile of each cutter in the standard and special groups to be accurately set out. The dimensions in the table are calculated for1D.P.: for any other pitch, the dimensions must be divided by the corresponding value of the diametral pitch. (See Figure 3.) Cutter number
40、Inclusive range of teeth for spur gears 1 2 3 135to rack 55to134 35to54 4 5 6 26to34 21to 25 17to 20 7 8 14to16 12and13 Cutter number Inclusive range of teeth for spur gears 1 1“ 2 135to rack 80to134 55to 79 2“ 3 3“ 42to54 35to 41 30to 34 4 4“ 5 26to29 23to 25 21and22 5“ 6 6“ 19and20 17and18 15and16
41、 7 7“ 8 14 13 12BS2518-1:1954 4 BSI 01-2000 Figure 2 20 composite basic rack tooth profile for unit normal diametral pitchBS 2518-1:1954 BSI 01-2000 5 NOTEIn setting out the profile, CT is marked on the datum line, and the centre of the arc of radius R1is located by the co-ordinates A1and B1. This a
42、rc does not necessarily pass through the intersection of the profile with the datum line. Figure 3 Cutters Nos. 1to 8 P.A. 20 Table 2BS 2518-1:1954 6 BSI 01-2000 Table 2 Profile dimensions for 1D.P. 20 P.A. rotary gear cutters Table 3 Limits of tolerances on standard chordal tooth thickness “CT” Cut
43、ter No. R1 A1 B1 R2 A2 R3 A3 R4 A4 R5 A5 B5 R6 R7 A7 CT a CA in. in. in. in. in. in. in. in. in. in. in. in. in. in. in. in. in. 1 23.209 8.188 21.716 2.966 0.598 0.250 5.331 1.271 1.571 1.246 1“ 13.684 4.923 12.768 2.920 0.637 0.250 5.597 1.321 1.571 1.242 2 9.425 3.462 8.766 2.884 0.686 0.250 6.01
44、1 1.413 1.571 1.239 2“ 7.994 3.024 7.400 2.852 0.733 6.431 2.433 0.250 6.404 1.494 1.570 1.235 3 6.826 2.635 6.297 2.820 0.769 5.424 2.085 0.250 6.870 1.582 1.570 1.232 3“ 5.876 2.308 5.404 2.797 0.809 4.434 1.742 0.250 7.435 1.700 1.570 1.229 4 7.850 3.349 7.094 2.435 0.654 4.446 1.770 3.114 1.299
45、0.250 9.222 2.181 1.570 1.226 4“ 7.394 3.253 6.634 2.361 0.655 3.933 1.594 2.603 1.121 0.250 9.920 2.304 1.569 1.223 5 7.101 3.203 6.329 2.302 0.655 3.591 1.477 2.264 1.003 0.250 12.218 2.856 1.569 1.221 5“ 3.730 1.554 3.392 2.871 1.066 2.979 1.237 0.250 9.921 2.040 1.569 1.218 6 3.716 1.615 3.347 2
46、.650 0.981 2.202 0.960 0.250 15.145 3.264 1.569 1.214 6“ 3.339 1.490 2.988 2.619 1.034 1.883 0.844 0.250 23.220 4.849 1.568 1.209 7 3.200 1.468 2.843 1.700 0.790 Join R3 & R5by a common tangent 0.900 0.520 1.100 0.434 1.567 1.206 7“ 1.765 0.814 1.566 3.060 1.438 1.360 0.671 Join R3 & R5by a common t
47、angent 0.880 0.535 1.074 0.456 1.567 1.203 8 1.830 0.849 1.621 2.920 1.407 1.094 0.579 4.742 1.357 0.860 0.518 1.038 0.480 1.566 1.199 a For limits see Table 3. Cutter sizes Limits of tolerance Cutter sizes Limits of tolerance in. Up to and including1# D.P. +0.012 +0.006 Over6D.P. up to and includin
48、g7D.P. +0.005 +0.001 Over1# D.P. up to and including3“ D.P. +0.010 +0.005 Over7D.P. up to and including9D.P. +0.004 +0.001 Over3“ D.P. up to and including4D.P. +0.008 +0.002 Over9D.P. up to and including18D.P. +0.003 +0.001 Over4D.P. Up to and including5D.P. +0.007 +0.002 Over18D.P. +0.0020 +0.0005
49、Over5D.P. up to and including6D.P. +0.006 +0.001 NOTEThe oversize tolerance for cutters of1to3“ D.P. includes an allowance for side relief. (See Appendix B.)BS2518-1:1954 BSI 01-2000 7 5 Cutter dimensions a) The cutter profiles shall be set out using the co-ordinates and radii in Table 2, divided by the diametral pitch. b) The tooth thickness (CT) and depth (CA) shall be as specified in the last two columns of Table 2, divided by th
