OBSOLESCENT OBSOLESCENT MAY 1986 MAY 1986
Specification for
Specification for
Metal washers —
Metal washers —
For general engineering purposes
For general engineering purposes
UDC 621.882.4 UDC 621.882.4
This British Standard, having This British Standard, having been approved by the
been approved by the Mechan
Mechanicalical EnginEngineeringeering Indust
Industryry StandStandards ards CommiCommitteettee and endorsed by the Chairman and endorsed by the Chairman of
of thethe EnginEngineering eering DivisioDivisionalnal Council, was published under Council, was published under the
the authorauthority of the Generality of the General Council on
Council on 1
1 SepSeptemtemberber 19619611 © BSI 02-2000 © BSI 02-2000
The following BSI references The following BSI references relate to the work on this relate to the work on this standard:
standard:
Committee references MEE/60 Committee references MEE/60 MEE/60/6
MEE/60/6
The Mechanical Engineering Industry Standards Committee, under whose The Mechanical Engineering Industry Standards Committee, under whose supervision this British Standard was prepared, consists of representatives supervision this British Standard was prepared, consists of representatives from the following Government departments and scientific and industrial from the following Government departments and scientific and industrial organizations:
organizations:
The Government departments and scientific and industrial organizations The Government departments and scientific and industrial organizations marked with an asterisk in the above list, together with the following, were marked with an asterisk in the above list, together with the following, were directly represented on the Committee entrusted with the preparation of this directly represented on the Committee entrusted with the preparation of this standard:
standard: Admiralty*
Admiralty* Gas CouncilGas Council
Air Ministry
Air Ministry High Commission of India*High Commission of India* Associated Offices’ Technical Committee
Associated Offices’ Technical Committee Institute of Marine EngineersInstitute of Marine Engineers Association of Consulting Engineers
Association of Consulting Engineers Institute of PetroleumInstitute of Petroleum ((IInnccoorrppoorraatteedd)) IInnssttiittuuttiioon n oof f CCiivviil l EEnnggiinneeeerrss Br
Brititisish h CChehemmicical al PlPlaant nt MaManunufafactctururerers’s’ IInsnstititututition on of of GaGas s EnEngginineeeersrs Association
Association Institution of Heating and VentilatingInstitution of Heating and Ventilating B
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Britistish h EleElectrctricaical l and and AllAllied ied ManManufaufactucturerrers’s’ InsInstittitutiution on of of MecMechanhanicaical l EngEngineeineersrs Association*
Association* Institution of Mechanical EngineersInstitution of Mechanical Engineers B
Brriittiissh h EEnnggiinneeeerrss’ ’ AAssssoocciiaattiioonn** ((AAuuttoommoobbiille e DDiivviissiioonn)) Br
Brititisish Gh Geaear Mr Mananufufacactuturerersrs’ A’ Assssocociaiatitionon InInststititututioion on of Pf Proroduductctioion En Engnginineeeersrs** B
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Maannuuffaaccttuurreerrss’ ’ AAssssoocciiaattiioonn** AssssoA occiiaattiioon n oof f GGrreeaat t BBrriittaaiinn** B
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Brititisish h CCycycle le & & MoMottor or CyCyccle le InInddusustrtrieiess RRololleled d TThrhreaead d ScScrerew w AAssssocociaiatitionon Association Limited
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Institute of Iron & Steel Wire Manufacturers
Amendments issued since publ
Amendments issued since publicationication Amd. No.
Contents
Page
Co-operating organizations Inside front cover
Foreword ii
Part 1: Bright metal washers
1 Scope 1
2 Material 1
3 Finish 1
4 Coating 1
5 Dimensions 1
Part 2: Black metal washers
6 Scope 8
7 Material 8
8 Finish 8
9 Dimensions 8
Table 1 — Small bright washers for use with B.A. and
American Number size fasteners 2
Table 2 — Large bright washers for use with B.A. and
American Number size fasteners 3
Table 3 — Small bright washers for use with UNC,
UNF, B.S.W and B.S.F fasteners 4
Table 4 — Large bright washers for use with UNC,
UNF, B.S.W. and B.S.F. fasteners 5
Table 5 — Medium bright washers for automobile
purposes for use with UNC, UNF, B.S.W and B.S.F. fasteners 6 Table 6 — Large bright washers for automobile purposes
for use with UNC, UNF, B.S.W. and B.S.F. fasteners 7
Table 7 — Ordinary black washers 9
Table 8 — Large black washers 10
Table 9 — Small light gauge black washers 11
Table 10 — Round black washers with square holes for
woodwork and timber constructions 12
Table 11 — Square black washers with round holes 13
This standard makes reference to the following British Standards: BS 15, Structural steel.
BS 265, Cold rolled brass sheet, strip and foil, copper content 61.5 per cent minimum and under 64 per cent maximum.
BS 309, Whiteheart malleable iron castings. BS 310, Blackheart malleable iron castings. BS 1449, Steel plate, sheet and strip.
This British Standard has been prepared under the authority of the Mechanical Engineering industry Standards Committee.
Tables for plain washers have hitherto been included in standards for bolts, screws and nuts, but it has been felt for some time that these provisions did not adequately represent either users’ requirements or current manufacturing practice. The present standard, which is intended to supersede these existing tables,1) accordingly provides for metal washers in a greater variety of diameters and thicknesses and is based upon what experience has shown to be th e greatest popular demand.
At first sight this may appear contrary to normal standardization procedure, but it is hoped that by establishing a standard series of metal washers which should meet most general engineering requirements, the demand for an unnecessary multiplicity of specials can in fact be eliminated.
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.
Summary of pages
This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 14 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.
1)Tables of washers which are superseded by this standard are contained in the following British
Standards:
BS 57, “ B.A. screws, bolts, nuts and plain washers”.
BS 325, “ Black cup and countersunk bolts, nuts and washers”. BS 916, “ Black bolts, screws and nuts”.
BS 1083, “ Precision hexagon bolts, screws, nuts and plain washers”.
BS 1768, “Unified precision hexagon bolts, screws, nuts (UNC and UNF threads) and plain washers — normal series”.
BS 1769, “Unified black hexagon bolts, screws, nuts and plain washers — heavy series”. BS 1981, “Unified machine screws and machine screw nuts”.
Part 1: Bright metal washers
1 Scope
Part 1 of this British Standard relates to bright metal washers for use with standard fasteners and for other general purposes.
Dimensions are given for large and small washers: one grade of thickness is specified for those intended for use with B.A. and American Number size
fasteners and two grades of thickness are specified for washers for use with Unified, B.S.W. and B.S.F. fasteners. In addition, tables of dimensions for bright washers for automobile use are included in this part of the standard.
General requirements for material and finish of bright washers are also given.
2 Material
Steel washers shall be made from En2 cold rolled steel in the hard condition in accordance with BS 1449, “Steel plate, sheet and strip ”.
Brass washers shall be made from material in the hard condition in accordance with BS 265, “Cold rolled brass sheet, strip and foil copper
content 61.5 per cent minimum and under 64 per cent maximum”.
If the purchaser requires the washers to be manufactured from steel or brass in any other condition, or of another material, he shall specify his requirements in his enquiry or order.
3 Finish
The washers shall be reasonably flat and free from burrs. Standard washers will normally be supplied unchamfered.
If chamfered washers are required this should be specified by the purchaser in his enquiry or order.
4 Coating
If the washers are required to have a protective or decorative finish, this shall be specified by the purchaser in his enquiry or order.
5 Dimensions
The dimensions of bright washers shall be in accordance with Table 1 to Table 6 inclusive.
Table 1 — Small bright washers for use with B.A. and American Number size fasteners
see Clause
3
1 2 3 4 5 6
B.A. No. American
No. size Diameter of hole A Outside diameter B Thicknessa C
max. min. max. min.
in in in in S.W.G. in 8 7 6 2 3 4 0.099 0.111 0.123 0.094 0.106 0.118 0.185 0.208 0.233 0.180 0.203 0.228 25 24 23 0.020 0.022 0.024 5 4 3 5 6 8 0.140 0.157 0.177 0.135 0.152 0.172 0.268 0.301 0.341 0.263 0.296 0.336 23 22 22 0.024 0.028 0.028 2 1 0 10 12 — 0.202 0.228 0.256 0.197 0.223 0.251 0.391 0.443 0.500 0.386 0.438 0.495 21 20 19 0.032 0.036 0.040 NOTE The sizes shown in heavy type are those which are designated “Preferred” in BS 57, “ B.A. screws, bolts, nuts and plain washers”.
Table 2 — Large bright washers for use with B.A. and American Number size fasteners
see Clause
3
1 2 3 4 5 6
B.A. AmericanNo. size
Diameter of hole
A
Outside diameter
B Thicknessa
C
max. min. max. min.
in in in in S.W.G. in 14 12 10 — — 0 0.049 0.061 0.078 0.044 0.056 0.073 0.097 0.130 0.176 0.092 0.125 0.171 27 27 27 0.016 0.016 0.016 9 8 7 1 2 3 0.086 0.099 0.111 0.081 0.094 0.106 0.197 0.228 0.257 0.192 0.223 0.252 27 25 22 0.016 0.020 0.028 6 5 4 4 5 6 0.123 0.140 0.157 0.118 0.135 0.152 0.288 0.335 0.378 0.283 0.330 0.373 20 20 19 0.036 0.036 0.040 3 2 1 8 10 12 0.177 0.202 0.228 0.172 0.197 0.223 0.432 0.500 0.565 0.427 0.495 0.560 19 18 18 0.040 0.348 0.048 0 — 0.256 0.251 0.625 0.620 17 0.056
NOTE The sizes shown in heavy type are those which are designated “Preferred” in BS 57, “ B.A. screws, bolts, nuts and plain washers”.
Table 3 — Small bright washers for use with UNC, UNF, B.S.W. and B.S.F. fasteners see Clause
3
1 2 3 4 5 6 7 Nominal size of bolt or screw Diameter of hole A Outside diameter B Thicknessa Cmax. min. max. min. Heavy gauge Light gauge
in in in in in S.W.G. in S.W.G. in 1/ 4 5/ 16 3/ 8 0.270 0.333 0.395 0.265 0.328 0.390 0.562 0.625 0.750 0.557 0.620 0.745 17 15 15 0.056 0.072 0.072 20 19 18 0.036 0.040 0.048 7/ 16 1/ 2 9/ 16 0.458 0.520 0.593 0.453 0.515 0.588 0.875 1.000 1.125 0.870 0.995 1.115 13 13 12 0.092 0.092 0.104 18 17 17 0.048 0.056 0.056 5/ 8 3/ 4 7/ 8 0.656 0.781 0.906 0.651 0.776 0.901 1.250 1.500 1.625 1.240 1.490 1.615 11 10 9 0.116 0.128 0.144 15 15 15 0.072 0.072 0.072 1 11/ 8 11/ 4 1.031 1.156 1.281 1.026 1.151 1.276 1.875 2.125 2.375 1.865 2.115 2.355 8 7 7 0.160 0.176 0.176 15 13 11 0.072 0.092 0.116 13/ 8 11/ 2 13/ 4 1.406 1.531 1.781 1.401 1.526 1.776 2.625 2.875 3.375 2.605 2.855 3.345 6 6 5 0.192 0.192 0.212 — — — — — — 2 2.031 2.026 3.625 3.595 5 0.212 — —
aSubject to the normal manufacturing tolerances on the sheet or strip as specified in the appropriate British Standards.
NOTE Attention is drawn to the fact that when small fractional size washers not tabulated here are required, the following B.A. sizes, for which dimensions are given in Table 1, are suitable.
For inch size use B.A. size For inch size use B.A. size
3/ 32 1/ 8 5/ 32 7 5 3 3/ 16 7/ 32 2 1
Table 4 — Large bright washers for use with UNC, UNF, B.S.W. and B.S.F. fasteners see Clause
3
1 2 3 4 5 6 7 Nominal size of bolt or screw Diameter of hole A Outside diameter B Thicknessa Cmax. min. max. min. Heavy gauge Light gauge
in in in in in S.W.G. in S.W.G. in 1/ 4 5/ 16 3/ 8 0.270 0.333 0.395 0.265 0.328 0.390 0.625 0.750 0.875 0.620 0.745 0.870 17 15 15 0.056 0.072 0.072 19 18 18 0.040 0.048 0.048 7/ 16 1/ 2 9/ 16 0.458 0.520 0.593 0.453 0.515 0.588 1.000 1.125 1.250 0.995 1.115 1.240 13 13 12 0.092 0.092 0.104 17 17 17 0.056 0.056 0.056 5/ 8 3/ 4 7/ 8 0.656 0.781 0.906 0.651 0.776 0.901 1.375 1.625 1.875 1.365 1.615 1.865 11 10 9 0.116 0.128 0.144 15 15 15 0.072 0.072 0.072 1 11/ 8 11/ 4 1.031 1.156 1.281 1.026 1.151 1.276 2.125 2.375 2.625 2.115 2.355 2.605 8 7 7 0.160 0.176 0.176 13 12 11 0.092 0.104 0.116 13/ 8 11/ 2 13/ 4 1.406 1.531 1.781 1.401 1.526 1.776 2.875 3.125 3.625 2.855 3.095 3.595 6 6 5 0.192 0.192 0.212 10 10 10 0.128 0.128 0.128 2 2.031 2.026 4.125 4.095 5 0.212 10 0.128
aSubject to the normal manufacturing tolerances on the sheet or strip as specified in the appropriate British Standards.
NOTE Attention is drawn to the fact that when small fractional size washers not tabulated here are required, the following B.A. sizes, for which dimensions are given in Table 2, are suitable.
For inch size use B.A. size For inch size use B.A. size
1/ 16 3/ 32 10 7 5/ 32 3/ 16 3 2
Table 5 — Medium bright washers for automobile purposes for use with UNC, UNF, B.S.W. and B.S.F. fasteners
1 2 3 4 5 6 Nominal size of bolt or screw Diameter of hole A Outside diameter B Thicknessa C
max. min. max. min.
in in in in in S.W.G. in 1/ 4 5/ 16 3/ 8 0.270 0.333 0.395 0.265 0.328 0.390 0.750 0.875 1.000 0.745 0.870 0.995 16 15 14 0.064 0.072 0.080 7/ 16 1/ 2 9/ 16 0.458 0.520 0.593 0.453 0.515 0.588 1.125 1.250 1.375 1.115 1.240 1.365 13 12 11 0.092 0.104 0.116 5/ 8 3/ 4 7/ 8 0.656 0.781 0.906 0.651 0.776 0.901 1.625 1.875 2.125 1.615 1.865 2.115 10 9 8 0.128 0.144 0.160 1 1.031 1.026 2.375 2.355 6 0.192
Table 6 — Large bright washers for automobile purposes for use with UNC, UNF, B.S.W. and B.S.F. fasteners
1 2 3 4 5 6 Nominal size of bolt or screw Diameter of hole A Outside diameter B Thicknessa C
max. min. max. min.
in in in in in S.W.G. in 1/ 4 5/ 16 3/ 8 0.270 0.333 0.395 0.265 0.328 0.390 1.000 1.250 1.375 0.995 1.240 1.365 16 14 13 0.064 0.080 0.092 7/ 16 1/ 2 9/ 16 0.458 0.520 0.593 0.453 0.515 0.588 1.500 1.625 1.750 1.490 1.615 1.740 12 11 10 0.104 0.116 0.128 5/ 8 3/ 4 7/ 8 0.656 0.781 0.906 0.651 0.776 0.901 2.000 2.250 2.500 1.990 2.240 2.480 10 9 8 0.128 0.144 0.160 1 1.031 1.026 2.750 2.730 6 0.192
6 Scope
Part 2 of this British Standard relates to black steel washers and malleable cast iron washers for use with standard bolts and for other general purposes. Dimensions are specified for the following types of washers:
ordinary black washers; large black washers;
small light gauge black washers;
round black washers with square holes for woodwork and timber;
square black washers with round holes;
steel or malleable cast iron square or D-shaped taper washers.
General requirements for material and finish are also given.
NOTE The washers specified in this standard are not suitable for use with the fasteners covered by BS 3139, “High strength friction grip bolts for structural engineering ” which includes its
own provision for washers.
7 Material
a) Steel washers.
i) Flat. Unless otherwise specified, flat washers shall be made from mild steel. ii) Taper. Taper washers shall be made from mild steel to BS 15, “Structural steel” with a tensile strength of 28/33 tons per sq in.
b) Malleable cast iron type. These shall be made from either
i) Malleable cast iron (whiteheart) in accordance with BS 309, “Whiteheart malleable iron castings.”
or
ii) Malleable cast iron (blackheart) in accordance with BS 310, “ Blackheart malleable iron castings.”
8 Finish
The faces of the washers shall be reasonably flat, smooth and free from burrs.
9 Dimensions
a) The dimensions of round black washers with round holes shall be in accordance with Table 7, Table 8 and Table 9.
b) The dimensions of round black washers with square holes shall be in accordance with
Table 10.
c) The dimensions of square black washers with round holes shall be in accordance with Table 11. d) The dimensions of square or D-shaped black taper washers shall be in accordance with Table 12.
Table 7 — Ordinary black washers
1 2 3 4
Nominal size of bolt Diameter of holeTolerance +1 / A 32 in Outside diameter B ThicknessC Tolerance± 1 gauge in in in S.W.G. in 1/ 4 5/ 16 3/ 8 9/ 32 11/ 32 13/ 32 5/ 8 3/ 4 7/ 8 16 14 14 0.064 0.080 0.080 7/ 16 1/ 2 9/ 16 15/ 32 9/ 16 5/ 8 1 11/ 8 11/ 4 12 12 10 0.104 0.104 0.128 5/ 8 3/ 4 7/ 8 11/ 16 13/ 16 15/ 16 13/ 8 15/ 8 17/ 8 10 9 8 0.128 0.144 0.160 1 11/ 8 11/ 4 11/ 16 13/ 16 13/ 8 21/ 8 23/ 8 25/ 8 7 7 6 0.176 0.176 0.192 13/ 8 11/ 2 15/ 8 11/ 2 15/ 8 13/ 4 27/ 8 31/ 8 33/ 8 6 6 5 0.192 0.192 0.212 13/ 4 17/ 8 2 17/ 8 2 21/ 8 35/ 8 37/ 8 41/ 8 5 5 5 0.212 0.212 0.212
Table 8 — Large black washers
1 2 3 4
Nominal size of bolt Diameter of holeTolerance +1 / A 32 in Outside diameter B ThicknessC Tolerance± 1 gauge in in in S.W.G. in 1/ 4 5/ 16 3/ 8 9/ 32 11/ 32 13/ 32 3/ 4 7/ 8 1 12 12 12 0.104 0.104 0.104 7/ 16 1/ 2 9/ 16 15/ 32 9/ 16 5/ 8 11/ 8 11/ 4 13/ 8 12 12 10 0.104 0.104 0.128 5/ 8 3/ 4 7/ 8 11/ 16 13/ 16 15/ 16 11/ 2 13/ 4 2 10 9 8 0.128 0.144 0.160 1 11/ 8 11/ 4 11/ 16 13/ 16 13/ 8 21/ 4 21/ 2 23/ 4 7 7 6 0.176 0.176 0.192 13/ 8 11/ 2 15/ 8 11/ 2 15/ 8 13/ 4 3 31/ 4 31/ 2 6 6 5 0.192 0.192 0.212 13/ 4 17/ 8 2 17/ 8 2 21/ 8 33/ 4 4 41/ 4 5 5 5 0.212 0.212 0.212
Table 9 — Small light gauge black washers
1 2 3 4
Nominal size of bolt Diameter of hole A Tolerance +1 / 32 in Outside diameter B ThicknessC Tolerance± 1 gauge in in in S.W.G. in 1/ 4 5/ 16 3/ 8 9/ 32 11/ 32 13/ 32 9/ 16 5/ 8 3/ 4 16 16 16 0.064 0.064 0.064 7/ 16 1/ 2 9/ 16 15/ 32 17/ 32 19/ 32 7/ 8 1 11/ 8 16 16 14 0.064 0.064 0.080 5/ 8 3/ 4 7/ 8 21/ 32 25/ 32 29/ 32 11/ 4 11/ 2 15/ 8 14 14 14 0.080 0.080 0.080 1 11/ 8 11/ 4 11/ 32 15/ 32 19/ 32 17/ 8 21/ 8 23/ 8 14 14 14 0.080 0.080 0.080 13/ 8 11/ 2 113/ 32 117/ 32 25/ 8 27/ 8 14 14 0.080 0.080
Table 10 — Round black washers with square holes for woodwork and timber constructions
1 2 3 4
Nominal size of bolt Tolerance + Width of hole1 / A 32 in Outside diameter B ThicknessC Tolerance± 1 gauge in in in S.W.G. in 3/ 8 1/ 2 5/ 8 7/ 16 9/ 16 11/ 16 11/ 4 11/ 2 2 11 10 9 0.116 0.128 0.144 3/ 4 7/ 8 1 13/ 16 15/ 16 11/ 16 21/ 4 25/ 8 3 8 5 5 0.160 0.212 0.212
Table 11 — Square black washers with round holes
1 2 3 4
Nominal size of bolt Diameter of holeTolerance +1 / A 32 in Outside square B ThicknessC Tolerance± 1 gauge in in in S.W.G. in 3/ 8 7/16 11/ 2 10 0.128 2 1/ 2 9/16 11/ 2 10 0.128 2 5/ 8 11/16 2 10 0.128 3 6 0.192 3 0.252 3/ 4 13/16 21/ 2 10 0.128 3 6 0.192 3 3 0.252 4 7/ 8 15/16 21/ 2 10 0.128 3 3 0.252 1 11/ 16 3 3 0.252 4 4 3/0 0.372 11/ 4 13/8 4 3 0.252 3/0 0.372
Table 12 — Square or D-shaped taper washers
1 2 3 4
Nominal size of bolt
Diameter of hole>
A Overall size
B Mean thickness C Tolerance +1 / 32 in 3° and 5° 8° in in in in in 3/ 8 1/ 2 5/ 8 7/ 16 9/ 16 11/ 16 1 11/ 4 11/ 2 3/ 16 3/ 16 3/ 16 1/ 4 1/ 4 1/ 4 3/ 4 7/ 8 1 13/ 16 15/ 16 11/ 16 13/ 4 2 21/ 4 3/ 16 3/ 16 3/ 16 1/ 4 1/ 4 1/ 4
* Angle of taper may be 3°, 5° or 8°.
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