1、BRITISH STANDARD CONFIRMED JANUARY1984 BS 328-2:1972 Specification for Twist drills and combined drills and countersinks Part 2: Combined drills and countersinks (centre drills) UDC 621.951.4BS328-2:1972 This British Standard, having been approved by the Mechanical Engineering Industry Standards Com
2、mittee, was published under the authority of the Executive Board on 28 July 1972 BSI 03-1999 First published, June 1928 First revision, August 1950 Second revision, July 1972 The following BSI references relate to the work on this standard: Committee reference MEE/73 Draft for approval 71/37365 ISBN
3、 0580 07015 8 Co-operating organizations The Mechanical 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: Associated Offices Technica
4、l Committee Engineering Equipment Users Association Association of Consulting Engineers Gas Council Association of Hydraulic Equipment Institution of Civil Engineers Manufacturers Ltd. Institution of Gas Engineers Association of Mining, Electrical and Institution of Heating and Ventilating Mechanica
5、l Engineers Engineers British Compressed Air Society Institution of Mechanical Engineers British Electrical and Allied Manufacturers Institution of Mechanical Engineers Association* (Automobile Division) British Gear Manufacturers Association Institution of Plant Engineers British Internal Combustio
6、n Engine Institution of Production Engineers* Manufacturers Association Locomotive and Allied Manufacturers British Mechanical Engineering Association of Great Britain Confederation London Transport Executive British Pump Manufacturers Association Machine Tool Trades Association* British Steel Indus
7、try Ministry of Defence Crown Agents for Oversea Governments and Ministry of Defence, Army Department Administrations National Coal Board Department of Employment and Productivity National Physical Laboratory (H.M. Factory Inspectorate) (Department of Trade and Industry) Department of the Environmen
8、t Process Plant Association Department of Trade and Industry Royal Institute of British Architects Department of Trade and Industry Telecommunications Engineering National Engineering Laboratory Manufacturing Association Electricity Council, the Central Electricity Water Tube Boilermakers Associatio
9、n Generating Board and the Area Boards in England and Wales The scientific and industrial organizations marked with an asterisk in the above list, together with the following, were directly represented on the committee entrusted with the preparation of this British Standard: Society of Motor Manufac
10、turers and Twist Drill Association Traders Ltd. Amendments issued since publication Amd. No. Date CommentsBS328-2:1972 BSI 03-1999 i Contents Page Co-operating organizations Inside front cover Foreword ii 1 Scope 1 2 Manufacturing requirements for combined drills and countersinks (centre drills) 1 3
11、 Dimensions of combined drills and countersinks (centre drills) 1 4 Designation 1 5 Combined drills and countersinks (centre drills) for centre holes without protecting chamfer. Type A 2 6 Combined drills and countersinks (centre drills) for centre holes with protecting chamfer. Type B 3 7 Combined
12、drills and countersinks (centre drills) for centre holes with radius form. Type R 4 Appendix A Recommended dimensions for centre holes. Type A 6 Appendix B Recommended dimensions for centre holes. Type B 7 Appendix C Recommended dimensions for centre holes. Type R 8 Figure 1 Single-ended combined dr
13、ills and countersinks (centre drills). Type A (d 1mm) 2 Figure 3 Combined drills and countersinks (centre drills). Type B 3 Figure 4 Combined drills and countersinks (centre drills). Type R 4 Figure 5 Type A centre hole 6 Figure 6 Type B centre hole 7 Figure 7 Type R centre hole 8 Table 1 Dimensions
14、 of combined drills and countersinks (centre drills). Type A 3 Table 2 Dimensions of combined drills and countersinks (centre drills). Type B 4 Table 3 Dimensions of combined drills and countersinks (centre drills). Type R 5 Table 4 Dimensions for centre holes. Type A 6 Table 5 Dimensions for centre
15、 holes. Type B 7 Table 6 Dimensions for centre holes. Type R 8BS328-2:1972 ii BSI 03-1999 Foreword In order to keep abreast of progress in the industries concerned, British Standards are subject to periodical review. Suggestions for improvements will be recorded and in due course brought to the noti
16、ce of the committees charged with the revision of the standards to which they refer. A complete list of British Standards, numbering over 9,000, fully indexed and with a note of the contents of each, will be found in the BSI Catalogue which may be purchased from BSI Sales Department. The Catalogue m
17、ay be consulted in many public libraries and similar institutions. The subject of combined drills and countersinks was first dealt with in BS985, which was published in1941 as a war emergency British Standard at the request of the Ministry of Supply. The contents of BS985 were incorporated in a revi
18、sion of BS328 in1950, becoming Part2 of that standard when BS985 was withdrawn. This latest revision of this Part of this British Standard, prepared under the authority of the Mechanical Engineering Industry Standards Committee, has been undertaken in order that this Part may be in agreement with Dr
19、aft International Standards DIS2540 1)and DIS2541 2)and ISO Recommendation R866 3) , which have been formulated by the International Organization for Standardization. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible
20、 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 to8 and a back cover. This standard has been updated (see copyright date)
21、and may have had amendments incorporated. This will be indicated in the amendment table on theinside front cover. 1) Draft International Standard ISO/DIS2540, “Centre drills for centre holes with protecting chamfer. Type B”. 2) Draft International Standard ISO/DIS2541, “Centre drills for centre hole
22、s with radius form. Type R”. 3) ISO Recommendation R866, “Centre drills for centre holes without protecting chamfer. TypeA”.BS328-2:1972 BSI 03-1999 1 1 Scope This Part of this British Standard gives designations and dimensions for the following types of centre drills. 1) Type A, combined drills and
23、 countersinks (centre drills) for centre holes without protecting chamfers. 2) Type B, combined drills and countersinks (centre drills) for centre holes with protecting chamfers. 3) Type R, combined drills and countersinks (centre drills) for centre holes with radius form. Appendix A, Appendix B and
24、 Appendix C show the recommended dimensions for centre holes. 2 Manufacturing requirements for combined drills and countersinks (centre drills) Combined drills and countersinks (centre drills) shall comply with the following requirements. 1) The drills shall be sharpened ready for use and shall be w
25、ell finished. 2) The flutes shall be so designed that the cutting lips are equal. 3) The pilot drill is to be provided with adequate back taper and relief. 4) The countersink shall be ground to provide lip clearance. The included angle shall be60 maximum, each lip being equally inclined to the axis.
26、 5) The body of the drill shall be truly cylindrical and the body, the drill and the drill point shall be truly co-axial. 6) The flutes may be straight or spiral at the option of the manufacturer. 7) The drills shall be right-hand cutting unless otherwise specified. 3 Dimensions of combined drills a
27、nd countersinks (centre drills) The three standard types of combined drills and countersinks (centre drills) shall be made in accordance with the dimensions given in Table 1, Table 2 or Table 3, as appropriate. 4 Designation Combined drills and countersinks (centre drills) shall be designated by the
28、 Type, the pilot diameter d and the body diameter d 1 . Examples of designations:A0.63/3.15 B 1.6/6.3 R 1.6/4BS328-2:1972 2 BSI 03-1999 5 Combined drills and countersinks (centre drills) for centre holes without protecting chamfer. Type A Type A single-ended and double-ended combined drills and coun
29、tersinks are illustrated in Figure 1 and Figure 2 and the dimensions of these shall be in accordance with Table 1. Figure 1 Single-ended combined drills and countersinks (centre drills). Type A (d 1mm)BS328-2:1972 BSI 03-1999 3 Table 1 Dimensions of combined drills and countersinks (centre drills) T
30、ype A 6 Combined drills and countersinks (centre drills) for centre holes with protecting chamfer. Type B Type B combined drills and countersinks are illustrated in Figure 3 and the dimensions shall be in accordance with Table 2. All dimensions are in millimetres. d d 1 l L k12 h9 max. min. max. min
31、. (0.5) 3.15 1.0 0.8 21 19 (0.63) 1.2 0.9 (0.8) 1.5 1.1 1.0 1.9 1.3 33.5 29.5 (1.25) 2.2 1.6 1.6 4.0 2.8 2.0 37.5 33.5 2.0 5.0 3.3 2.5 42 38 2.5 6.3 4.1 3.1 47 43 3.15 8.0 4.9 3.9 52 48 4.0 10.0 6.2 5.0 59 53 (5.0) 12.5 7.5 6.3 66 60 6.3 16.0 9.2 8.0 74 68 (8.0) 20.0 11.5 10.1 83 77 10.0 25.0 14.2 1
32、2.8 103 97 NOTESizes in brackets should be avoided whenever possible. Figure 3 Combined drills and countersinks (centre drills). Type BBS328-2:1972 4 BSI 03-1999 Table 2 Dimensions of combined drills and countersinks (centre drills). Type B 7 Combined drills and countersinks (centre drills) for cent
33、re holes with radius form. Type R Type R combined drills and countersinks are illustrated in Figure 4 and the dimensions shall be in accordance with Table 3. All dimensions are in millimetres. d d 1 d 2 l L k12 h9 k12 max. min. max. min. 1.0 4.0 2.12 1.9 1.3 37.5 33.5 (1.25) 5.0 2.65 2.2 1.6 42 38 1
34、.6 6.3 3.35 2.8 2.0 47 43 2.0 8.0 4.25 3.3 2.5 52 48 2.5 10.0 5.30 4.1 3.1 59 53 3.15 11.2 6.70 4.9 3.9 63 57 4.0 14.0 8.50 6.2 5.0 70 64 (5.0) 18.0 10.60 7.5 6.3 78 72 6.3 20.0 13.20 9.2 8.0 83 77 (8.0) 25.0 17.00 11.5 10.1 103 97 10.0 31.5 21.20 14.2 12.8 128 122 NOTESizes in brackets should be av
35、oided whenever possible. Figure 4 Combined drills and countersinks (centre drills). Type RBS328-2:1972 BSI 03-1999 5 Table 3 Dimensions of combined drills and countersinks (centre drills). Type R All dimensions are in millimetres. d d 1 Radius, r l L k12 h9 max. min. (approx.) max. min. 1.0 3.15 3.1
36、5 2.5 3.0 33.5 29.5 (1.25) 3.15 4.0 3.15 3.3 33.5 29.5 1.6 4.0 5.0 4.0 4.25 37.5 33.5 2.0 5.0 6.3 5.0 5.4 42 38 2.5 6.3 8.0 6.3 6.7 47 43 3.15 8.0 10.0 8.0 8.5 52 48 4.0 10.0 12.5 10.0 10.6 59 53 (5.0) 12.5 16.0 12.5 13.2 66 60 6.3 16.0 20.0 16.0 17.0 74 68 (8.0) 20.0 25.0 20.0 21.1 83 77 10.0 25.0
37、31.5 25.0 26.8 103 97 NOTESizes in brackets should be avoided whenever possible.BS328-2:1972 6 BSI 03-1999 Appendix A Recommended dimensions for centre holes. Type A A Type A centre hole is illustrated in Figure 5 and recommended dimensions are shown in Table 4. Table 4 Dimensions for centre holes.
38、Type A Figure 5 Type A centre hole All dimensions are in millimetres. d l D nominal min. nominal (0.5) 0.8 1.06 (0.63) 0.9 1.32 (0.8) 1.1 1.70 1.0 1.3 2.12 (1.25) 1.6 2.65 1.6 2.0 3.35 2.0 2.5 4.25 2.5 3.1 5.30 3.15 3.9 6.70 4.0 5.0 8.50 (5.0) 6.3 10.60 6.3 8.0 13.20 (8.0) 10.1 17.00 10.0 12.8 21.20
39、 NOTESizes in brackets should be avoided whenever possible.BS328-2:1972 BSI 03-1999 7 Appendix B Recommended dimensions for centre holes. Type B A Type B centre hole is illustrated in Figure 6 and recommended dimensions are shown in Table 5. Table 5 Dimensions for centre holes. Type B Figure 6 Type
40、B centre hole All dimensions are in millimetres. d l D nominal min. nominal 1.0 1.3 3.15 (1.25) 1.6 4.0 1.6 2.0 5.0 2.0 2.5 6.3 2.5 3.1 8.0 3.15 3.9 10.0 4.0 5.0 12.5 (5.0) 6.3 16.0 6.5 8.0 18.0 (8.0) 10.1 22.4 10.0 12.8 28.0 NOTESizes in brackets should be avoided whenever possible.BS328-2:1972 8 B
41、SI 03-1999 Appendix C Recommended dimensions for centre holes. Type R A Type R centre hole is illustrated in Figure 7 and recommended dimensions are shown in Table 6. Table 6 Dimensions for centre holes. Type R Figure 7 Type R centre hole All dimensions are in millimetres. d D nominal nominal 1.0 2.
42、12 (1.25) 2.65 1.6 3.35 2.0 4.25 2.5 5.30 3.15 6.70 4.0 8.50 (5.0) 10.60 6.3 13.20 (8.0) 17.00 10.0 21.20 NOTESizes in brackets should be avoided whenever possible.blankBS 328-2:1972 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsi
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