1、BRITISH STANDARD BS 325:1947 Incorporating Amendment Nos. 1, 2 and 3 Specification for Black cup and countersunk bolts and nuts UDC 621.882.072BS325:1947 This British Standard, having been approved by the MechanicalIndustry Committeeand endorsed by thechairman of the EngineeringDivisional Council,wa
2、s published undertheauthority of the GeneralCouncil on 17April1947 BSI 02-2000 First published February 1928 First revision April 1947 ISBN 0 580 34071 6 Co-operating organizations The Mechanical Industry Committee under whose supervision this British Standard was prepared consists of representative
3、s from the following Government departments and scientific and industrial organizations: Admiralty* Crown Agents for the Colonies Department of Scientific and Industrial Research High Commissioner for India* H.M. Office of Works* Home Office Ministry of Transport War Office* Agricultural and Road Ma
4、chinery Manufacturers Association Association of Consulting Engineers British Chemical Plant Manufacturers Association British Electrical and Allied Manufacturers Association British Engineers Association* British Iron and Steel Federation British Marine Oil Engine Manufacturers Association Engineer
5、ing Insurance Companies Institute of Marine Engineers Institute of Petroleum Institution of Automobile Engineers Institution of Civil Engineers Institution of Gas Engineers Institution of Heating and Ventilating Engineers Institution of Mechanical Engineers Institution of Production Engineers Locomo
6、tive Manufacturers Association Machine Tool Trades Association* Railway Companies of Great Britain The Government departments and scientific and industrial organizations marked with an asterisk in the above list, together with the following, were directly represented on the committee entrusted with
7、the preparation of this British Standard: National Physical Laboratory Black Bolt and Nut Association of Great Britain Boilermakers and Iron and Steel Shipbuilders Society British Constructional Steelwork Association Institution of Engineers and Shipbuilders in Scotland Institution of Naval Architec
8、ts North East Coast Institution of Engineers and Shipbuilders Railway Carriage and Wagon Builders and Financiers Parliamentary Association Railway Companies of Great Britain Amendments issued since publication Amd. No. Date of issue Comments 1895 May 1954 4330 October 1961 5904 August 1966 Indicated
9、 by a sideline in the marginBS325:1947 BSI 02-2000 i Amendment No. 3, published 11 August, 1966 to BS 325:1947 Black cup and countersunk bolts and nuts At a fully representative conference held on23rdNovember,1965 consideration was given to the action to be taken in relation to the move to metric as
10、 far as British Standards for screw threads were concerned and it was decided that: British industry should be strongly recommended to adopt the internationally agreed ISO metric threads 1)or ISO inch threads 2)but that the ISO inch threads should be regarded as second choice. The implementation of
11、this recommendation means that B.A., B.S.F. and B.S.W. threads should become obsolescent and should not be used in new designs. ACCORDINGLY IT HAS BEEN AGREED THAT BS 325 BE RENDERED OBSOLESCENT: IT WILL BE MADE OBSOLETE IN DUE COURSE. NOTEAn equivalent metric standard is in course of preparation. 1
12、) BS 3643, “ISO metric screw threads”. 2) BS 1580, “Unified screw threads”.ii blankBS325:1947 BSI 02-2000 iii Contents Page Co-operating organizations Inside front cover Foreword iv 1 Material 1 2 Dimensions 1 3 Screw threads 1 4 Ends of bolts 1 5 Length 1 6 Length of thread 1 7 Chamfering of nuts 1
13、 Figure 1 2 Figure 2 3 Figure 3 4 Figure 4 5 Figure 5 6 Figure 6 7 Figure 7 Hexagon nut 8 Figure 8 Square nut 8 Table 1 Black cup square neck bolts 2 Table 2 Black cup oval neck bolts 3 Table 3 Black cup nibbed bolts for iron and steel work 4 Table 4 Black countersunk nibbed bolts and countersunk ro
14、und bolts 5 Table 5 Black countersunk square neck bolts for iron and steel work 6 Table 6 Black countersunk square neck bolts for woodwork 7 Table 7 Black hexagon and square nuts 8BS325:1947 iv BSI 02-2000 Foreword This British Standard requires reference to the following: BS 84, Screw threads of Wh
15、itworth form. NOTEThe requirements for washers in this standard have been superseded by the publication of BS3410, “Metal washers for general engineering purposes”, to which reference should now be made. BS325 for cup and countersunk bolt heads, nuts and washers was first issued in1928, and that fir
16、st edition was limited to the standardization of the dimensions of the heads of the bolts, and of the nuts and washers for use with such bolts. The present edition, prepared under the authority of the Mechanical Engineering Industry Committee, has been extended in its scope to include requirements w
17、hich define the dimensions of the complete bolts, and indicate the quality of the material. The revision has, however, been prepared primarily to give effect to certain desirable changes in the proportions of the bolt heads. Principal amongst these changes is the adoption of two uniform angles of co
18、untersink in place of the variety of angles formerly standardized, whilst in all types of heads some small changes have been made in the dimensions in order to facilitate manufacture. The nuts standardized in this revision are those now established for general engineering in BS916, “Black bolts and
19、nuts.” It is recognised, however, that there are certain applications in heavy engineering work and in special corrosive situations for which the use of the old large (Whitworth) size nuts might be desirable and the manufacturers are prepared to supply such nuts for these special applications. A Bri
20、tish 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. Summary of pages This document comprises a fro
21、nt cover, an inside front cover, pagesitoiv, pages1to8 and 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 front cover.BS325:1947 BSI 02-2000 1 1 Material Unless otherwise specifie
22、d by the purchaser, the bolts and nuts shall be manufactured from steel having an ultimate tensile stress of not less than26tons per sq. in. 2 Dimensions The bolts and nuts shall comply with the dimensions given in Table 1 toTable 7, and shall be neatly and cleanly made. NOTEThe dimensions inTable 1
23、 toTable 6 are derived from the formulae given at the foot of each table. For uniformity the decimal dimensions are given throughout to the nearest0.001in., but these calculated dimensions are necessarily subject to appropriate manufacturing tolerances. 3 Screw threads The screw threads shall be BS
24、Whitworth, and shall be parallel throughout their length. The threads may be either cut or rolled at the option of the manufacturer, but shall conform to the limits and tolerances for “free class” specified in BS84:1956, “Screw threads of Whitworth form.” 4 Ends of bolts The ends of the bolts may, a
25、t the option of the manufacturer, be finished with either a radius (approximately equal to the diameter of the shank) or with a chamfered flat, or with the normal finish obtained during manufacture in the process of thread rolling, no other machining in this latter case being necessary. 5 Length The
26、 nominal length of the bolts shall be the distance from the underside of the head in the case of cup bolts, and the upper surface of the head in the case of countersunk bolts, to the farther end of the shank, the length of the machined point, if any, being regarded as part of the nominal length. 6 L
27、ength of thread The length of the screwed part of the bolt, defined as the distance from the end of the bolt (including any radiused or chamfered point) to the point to which the nut can be screwed by hand, shall be as follows: 7 Chamfering of nuts The nuts shall have a chamfer of approximately30 on
28、 one face, but may, at the option of the manufacturer, be similarly chamfered on both faces. Length of bolt Length of thread Up to and including 8 in. Twice the diameter of the bolt. Above 8 in. 2 1 / 2times the diameter of the bolt.BS325:1947 2 BSI 02-2000 Table 1 Black cup square neck bolts Figure
29、 1 1 2 3 4 5 6 7 Nominal diameter of bolt No. of threads per inch B.S.W. Diameter of head Depth of head Maximum depth of flash Depth of square neck Maximum radius under head D A B C E R in. in. in. in. in. in. 1 / 4 5 / 16 3 / 8 20 18 16 0.562 0.703 0.844 0.125 0.156 0.188 1 / 32 1 / 32 1 / 32 0.188
30、 0.234 0.281 1 / 32 1 / 32 1 / 32 7 / 16 1 / 2 5 / 8 14 12 11 0.984 1.125 1.406 0.250 0.281 0.375 1 / 32 1 / 32 1 / 16 0.328 0.375 0.469 1 / 32 1 / 32 3 / 64 3 / 4 7 / 8 1 10 9 8 1.688 1.969 2.250 0.438 0.500 0.562 1 / 16 3 / 32 3 / 32 0.562 0.656 0.750 3 / 64 1 / 16 1 / 16 Formul: A = 2.25 D. B = 1
31、 / 4in. to 3 / 8in. inclusive: .5 D. 7 / 16in. and 1 / 2in.: .5 D + 1 / 32in. 5 / 8in. to 1 in. inclusive: .5 D + 1 / 16in. E =.75 D.BS325:1947 BSI 02-2000 3 Table 2 Black cup oval neck bolts Figure 2 1 2 3 4 5 6 7 8 9 10 Nominal diameter of bolt No. of threads per inch B.S.W. Dia. of head Depth of
32、head Max. depth of flash Max. radius under head Oval neck Depth Major axis Radius Distance between centres D A B C R E F G H in. in. in. in. in. in. in. in. in. 3 / 4 7 / 8 10 9 1.688 1.969 0.438 0.500 1 / 16 3 / 32 3 / 64 1 / 16 0.625 0.625 1.000 1.125 0.375 0.438 0.250 0.250 Formul: A = 2.25 D. B
33、= .5 D + 1 / 16in. F = D + H. G = .5 D. H = .25 in.BS325:1947 4 BSI 02-2000 Table 3 Black cup nibbed bolts for iron and steel work Figure 3 1 2 3 4 5 6 7 8 9 Nominal diameter of bolt No. of threads per inch B.S.W. Diameter of head Depth of head Max. depth of flash Max. radius under head Nib Depth Pr
34、ojection Width A B C R E F G in. in. in. in. in. in. in. in. 1 / 4 5 / 16 3 / 8 20 18 16 0.500 0.625 0.750 0.188 0.234 0.281 1 / 32 1 / 32 1 / 32 1 / 32 1 / 32 1 / 32 0.125 0.156 0.188 0.062 0.078 0.094 0.062 0.078 0.094 7 / 16 1 / 2 5 / 8 14 12 11 0.875 1.000 1.250 0.328 0.375 0.469 1 / 32 1 / 32 1
35、 / 16 1 / 32 1 / 32 3 / 64 0.219 0.250 0.312 0.109 0.125 0.156 0.109 0.125 0.156 3 / 4 7 / 8 1 10 9 8 1.500 1.750 2.000 0.562 0.656 0.750 1 / 16 3 / 32 3 / 32 3 / 64 1 / 16 1 / 16 0.375 0.438 0.500 0.188 0.219 0.250 0.188 0.219 0.250 Formul: A = 2 D. B = .75 D. E = .5 D. F = .25 D. G = .25 D.BS325:1
36、947 BSI 02-2000 5 Table 4 Black countersunk nibbed bolts and countersunk round bolts 80 INCLUDED ANGLE Figure 4 1 2 3 4 5 6 Nominal diameter of bolt No. of threads per inch B.S.W. Diameter of head Maximum depth of flash Nib Depth Width D A B C E in. in. in. in. in. 1 / 4 5 / 16 3 / 8 20 18 16 0.459
37、0.574 0.690 1 / 32 1 / 32 1 / 32 0.218 0.234 0.280 0.062 0.078 0.094 7 / 16 1 / 2 5 / 8 14 12 11 0.805 0.920 1.149 3 / 64 3 / 64 3 / 64 0.327 0.358 0.420 0.109 0.125 0.156 3 / 4 7 / 8 1 10 9 8 1.379 1.609 1.839 1 / 16 1 / 16 1 / 16 0.509 0.561 0.625 0.188 0.219 0.250 Formul: A = 1.839 D. E = .25 D.B
38、S325:1947 6 BSI 02-2000 Table 5 Black countersunk square neck bolts for iron and steel work 80 INCLUDED ANGLE Figure 5 1 2 3 4 5 Nominal diameter of bolt No. of threads per inch B.S.W. Diameter of head Maximum depth of flash Total depth of head and square D A B C in. in. in. in. 3 / 8 7 / 16 1 / 2 1
39、6 14 12 0.690 0.805 0.920 1 / 32 3 / 64 3 / 64 0.313 0.375 0.422 5 / 8 3 / 4 7 / 8 11 10 9 1.149 1.379 1.609 3 / 64 1 / 16 1 / 16 0.515 0.625 0.719 1 8 1.839 1 / 16 0.812 Formul: A = 1.839 D. C =.75 D + B.BS325:1947 BSI 02-2000 7 Table 6 Black countersunk square neck bolts for woodwork 110 INCLUDED
40、ANGLE Figure 6 1 2 3 4 5 Nominal diameter of bolt No. of threads per inch B.S.W. Diameter of head Maximum depth of flash Total depth of head and square D A B C in. in. in. in. 1 / 4 5 / 16 3 / 8 20 18 16 0.625 0.781 0.938 1 / 32 1 / 32 1 / 32 0.350 0.429 0.509 7 / 16 1 / 2 5 / 8 14 12 11 1.094 1.250
41、 1.562 1 / 32 1 / 16 1 / 16 0.589 0.699 0.859 3 / 4 7 / 8 1 10 9 8 1.875 2.188 2.500 1 / 16 3 / 32 3 / 32 1.018 1.209 1.369 Formul: A = 2.5 D. C = 1.275 D + B.BS325:1947 8 BSI 02-2000 Table 7 Black hexagon and square nuts NOTESee Clause 7 re chamfering Figure 7 Hexagon nut Figure 8 Square nut 1 2 3
42、4 5 6 7 Nominal diameter of bolt Width across flats (hexagon and square) Approximate maximum dimension across corners Thickness (hexagon and square) A B C D Max. Min. Hexagon Square Max. Min. in. in. in. in. in. in. in. 1 / 4 5 / 16 3 / 8 0.445 0.525 0.600 0.435 0.515 0.585 0.51 0.61 0.69 0.63 0.74
43、0.85 0.22 0.27 0.33 0.20 0.25 0.31 7 / 16 1 / 2 5 / 8 0.710 0.820 1.010 0.695 0.800 0.985 0.82 0.95 1.17 1.00 1.16 1.43 0.39 0.46 0.60 0.37 0.43 0.56 3 / 4 7 / 8 1 1.200 1.300 1.480 1.175 1.270 1.450 1.39 1.50 1.71 1.70 1.84 2.09 0.72 0.81 0.93 0.68 0.75 0.87 NOTEThese dimensions for nuts are in acc
44、ord with BS 916, “Black bolts and nuts.”blankBS 325:1947 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the UK view on standards in Europe and at the international level. It is incor
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