BRITISH STANDARD

OBSOLESCENT MAY 1986

BS 3410:1961

Specification for

Metal washers —

For general engineering purposes

UDC 621.882.4

BS 3410:1961

This British Standard, having been approved by the Mechanical Engineering Industry Standards Committee and endorsed by the Chairman of the Engineering Divisional Council, was published under the authority of the General Council on1 September 1961

© BSI 02-2000

The following BSI references relate to the work on this standard:Committee references MEE/60 MEE/60/6Draft for comment A(MEE)4400

ISBN 0 580 34594 7

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:

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 the preparation of this standard:

Admiralty* Gas CouncilAir Ministry High Commission of India*Associated Offices’ Technical Committee Institute of Marine EngineersAssociation of Consulting Engineers Institute of Petroleum

(Incorporated) Institution of Civil EngineersBritish Chemical Plant Manufacturers’ Institution of Gas Engineers

Association Institution of Heating and VentilatingBritish Compressed Air Society EngineersBritish Electrical and Allied Manufacturers’ Institution of Mechanical Engineers

Association* Institution of Mechanical EngineersBritish Engineers’ Association* (Automobile Division)British Gear Manufacturers’ Association Institution of Production Engineers*British Internal Combustion Engine Locomotive and Allied Manufacturers’

Manufacturers’ Association* Association of Great Britain*British Iron and Steel Federation* Machine Tool Trades Association*British Railways, The British Transport Ministry of Labour (Factory Inspectorate)

Commission* Ministry of PowerCrown Agents for Oversea Governments and Ministry of Transport

Administrations* Ministry of WorksD.S.I.R. — National Engineering Laboratory National Coal BoardElectricity Council, The Generating Board and National Physical Laboratory (D.S.I.R.)*

the Area Boards in England and Wales Radio Industry Council*Engineering Equipment Users’ Association* War Office*

Agricultural Engineers’ Association London Transport Executive, The BritishBlack Bolt & Nut Association of Great Britain Transport CommissionBright Bolt & Nut Manufacturers’ Association Ministry of AviationBright Steel Bar Association Oil Companies Materials AssociationBritish Constructional Steelwork Association Post OfficeBritish Cycle & Motor Cycle Industries Rolled Thread Screw Association

Association Limited Screw Manufacturers’ AssociationCouncil of British Manufacturers of Petroleum Society of Motor Manufacturers & Traders

Equipment LimitedElectronic Engineering Association Washer Manufacturers’ AssociationHeat Treated Bolt Association Individual firmsInstitute of Iron & Steel Wire Manufacturers

Amendments issued since publication

Amd. No. Date Comments

BS 3410:1961

© BSI 02-2000 i

Contents

PageCo-operating organizations Inside front coverForeword iiPart 1: Bright metal washers1 Scope 12 Material 13 Finish 14 Coating 15 Dimensions 1Part 2: Black metal washers6 Scope 87 Material 88 Finish 89 Dimensions 8Table 1 — Small bright washers for use with B.A. and American Number size fasteners 2Table 2 — Large bright washers for use with B.A. and American Number size fasteners 3Table 3 — Small bright washers for use with UNC, UNF, B.S.W and B.S.F fasteners 4Table 4 — Large bright washers for use with UNC, UNF, B.S.W. and B.S.F. fasteners 5Table 5 — Medium bright washers for automobile purposes for use with UNC, UNF, B.S.W and B.S.F. fasteners 6Table 6 — Large bright washers for automobile purposes for use with UNC, UNF, B.S.W. and B.S.F. fasteners 7Table 7 — Ordinary black washers 9Table 8 — Large black washers 10Table 9 — Small light gauge black washers 11Table 10 — Round black washers with square holes for woodwork and timber constructions 12Table 11 — Square black washers with round holes 13Table 12 — Square or D-shaped taper washers 14

BS 3410:1961

ii © BSI 02-2000

Foreword

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 the 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 pagesThis 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”.BS 2466, “Black taper washers”.BS 2708, “Unified black square and hexagon bolts, screws and nuts (UNC and UNF threads) and plain washers — normal series”.

BS 3410:1961

© BSI 02-2000 1

Part 1: Bright metal washers

1 ScopePart 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 MaterialSteel 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 FinishThe 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 CoatingIf the washers are required to have a protective or decorative finish, this shall be specified by the purchaser in his enquiry or order.

5 DimensionsThe dimensions of bright washers shall be in accordance with Table 1 to Table 6 inclusive.

BS 3410:1961

2 © BSI 02-2000

Table 1 — Small bright washers for use with B.A. and American Number size fasteners

see Clause 31 2 3 4 5 6

B.A. No. American No. size

Diameter of holeA

Outside diameterB Thicknessa

Cmax. min. max. min.

in in in in S.W.G. in

876

234

0.0990.1110.123

0.0940.1060.118

0.1850.2080.233

0.1800.2030.228

252423

0.0200.0220.024

543

568

0.1400.1570.177

0.1350.1520.172

0.2680.3010.341

0.2630.2960.336

232222

0.0240.0280.028

210

1012—

0.2020.2280.256

0.1970.2230.251

0.3910.4430.500

0.3860.4380.495

212019

0.0320.0360.040

NOTE The sizes shown in heavy type are those which are designated “Preferred” in BS 57, “B.A. screws, bolts, nuts and plain washers”.a Subject to the normal manufacturing tolerances on the sheet or strip as specified in the appropriate British Standards.

BS 3410:1961

© BSI 02-2000 3

Table 2 — Large bright washers for use with B.A. and American Number size fasteners

see Clause 31 2 3 4 5 6

B.A. American No. size

Diameter of holeA

Outside diameterB Thicknessa

Cmax. min. max. min.

in in in in S.W.G. in

141210

——

0

0.0490.0610.078

0.0440.0560.073

0.0970.1300.176

0.0920.1250.171

272727

0.0160.0160.016

987

123

0.0860.0990.111

0.0810.0940.106

0.1970.2280.257

0.1920.2230.252

272522

0.0160.0200.028

654

456

0.1230.1400.157

0.1180.1350.152

0.2880.3350.378

0.2830.3300.373

202019

0.0360.0360.040

321

81012

0.1770.2020.228

0.1720.1970.223

0.4320.5000.565

0.4270.4950.560

191818

0.0400.3480.048

0 — 0.256 0.251 0.625 0.620 17 0.056NOTE The sizes shown in heavy type are those which are designated “Preferred” in BS 57, “B.A. screws, bolts, nuts and plain washers”.a Subject to the normal manufacturing tolerances on the sheet or strip as specified in the appropriate British Standards.

BS 3410:1961

4 © BSI 02-2000

Table 3 — Small bright washers for use with UNC, UNF, B.S.W. and B.S.F. fasteners

see Clause 31 2 3 4 5 6 7

Nominal size of bolt

or screw

Diameter of holeA

Outside diameterB

Thicknessa

C

max. min. max. min. Heavy gauge Light gauge

in in in in in S.W.G. in S.W.G. in1/45/163/8

0.2700.3330.395

0.2650.3280.390

0.5620.6250.750

0.5570.6200.745

171515

0.0560.0720.072

201918

0.0360.0400.048

7/161/29/16

0.4580.5200.593

0.4530.5150.588

0.8751.0001.125

0.8700.9951.115

131312

0.0920.0920.104

181717

0.0480.0560.056

5/83/47/8

0.6560.7810.906

0.6510.7760.901

1.2501.5001.625

1.2401.4901.615

11109

0.1160.1280.144

151515

0.0720.0720.072

111/811/4

1.0311.1561.281

1.0261.1511.276

1.8752.1252.375

1.8652.1152.355

877

0.1600.1760.176

151311

0.0720.0920.116

13/811/213/4

1.4061.5311.781

1.4011.5261.776

2.6252.8753.375

2.6052.8553.345

665

0.1920.1920.212

———

———

2 2.031 2.026 3.625 3.595 5 0.212 — —a Subject 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

3/321/8

5/32

753

3/167/32

21

BS 3410:1961

© BSI 02-2000 5

Table 4 — Large bright washers for use with UNC, UNF, B.S.W. and B.S.F. fasteners

see Clause 31 2 3 4 5 6 7

Nominal size of bolt

or screw

Diameter of holeA

Outside diameterB

Thicknessa

C

max. min. max. min. Heavy gauge Light gauge

in in in in in S.W.G. in S.W.G. in1/45/163/8

0.2700.3330.395

0.2650.3280.390

0.6250.7500.875

0.6200.7450.870

171515

0.0560.0720.072

191818

0.0400.0480.048

7/161/29/16

0.4580.5200.593

0.4530.5150.588

1.0001.1251.250

0.9951.1151.240

131312

0.0920.0920.104

171717

0.0560.0560.056

5/83/47/8

0.6560.7810.906

0.6510.7760.901

1.3751.6251.875

1.3651.6151.865

1110

9

0.1160.1280.144

151515

0.0720.0720.072

111/811/4

1.0311.1561.281

1.0261.1511.276

2.1252.3752.625

2.1152.3552.605

877

0.1600.1760.176

131211

0.0920.1040.116

13/811/213/4

1.4061.5311.781

1.4011.5261.776

2.8753.1253.625

2.8553.0953.595

665

0.1920.1920.212

101010

0.1280.1280.128

2 2.031 2.026 4.125 4.095 5 0.212 10 0.128a Subject 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

1/163/321/8

1075

5/323/167/32

321

BS 3410:1961

6 © BSI 02-2000

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 holeA

Outside diameterB Thicknessa

Cmax. min. max. min.

in in in in in S.W.G. in

1/45/163/8

0.2700.3330.395

0.2650.3280.390

0.7500.8751.000

0.7450.8700.995

161514

0.0640.0720.080

7/161/29/16

0.4580.5200.593

0.4530.5150.588

1.1251.2501.375

1.1151.2401.365

131211

0.0920.1040.116

5/83/47/8

0.6560.7810.906

0.6510.7760.901

1.6251.8752.125

1.6151.8652.115

1098

0.1280.1440.160

1 1.031 1.026 2.375 2.355 6 0.192a Subject to the normal manufacturing tolerances on the sheet or strip as specified in the appropriate British Standards.

BS 3410:1961

© BSI 02-2000 7

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 holeA

Outside diameterB Thicknessa

Cmax. min. max. min.

in in in in in S.W.G. in

1/45/163/8

0.2700.3330.395

0.2650.3280.390

1.0001.2501.375

0.9951.2401.365

161413

0.0640.0800.092

7/161/29/16

0.4580.5200.593

0.4530.5150.588

1.5001.6251.750

1.4901.6151.740

121110

0.1040.1160.128

5/83/47/8

0.6560.7810.906

0.6510.7760.901

2.0002.2502.500

1.9902.2402.480

1098

0.1280.1440.160

1 1.031 1.026 2.750 2.730 6 0.192a Subject to the normal manufacturing tolerances on the sheet or strip as specified in the appropriate British Standards.

BS 3410:1961

8 © BSI 02-2000

Part 2: Black metal washers

6 ScopePart 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 Materiala) 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.”orii) Malleable cast iron (blackheart) in accordance with BS 310, “Blackheart malleable iron castings.”

8 FinishThe faces of the washers shall be reasonably flat, smooth and free from burrs.

9 Dimensionsa) 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 withTable 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 withTable 12.

BS 3410:1961

© BSI 02-2000 9

Table 7 — Ordinary black washers

1 2 3 4

Nominal size of bolt Diameter of hole A Tolerance + 1/32 in

Outside diameter B

Thickness CTolerance ± 1 gauge

in in in S.W.G. in

1/45/163/8

9/3211/3213/32

5/83/47/8

161414

0.0640.0800.080

7/161/29/16

15/329/165/8

111/811/4

121210

0.1040.1040.128

5/83/47/8

11/1613/1615/16

13/815/817/8

1098

0.1280.1440.160

111/811/4

11/1613/1613/8

21/823/825/8

776

0.1760.1760.192

13/811/215/8

11/215/813/4

27/831/833/8

665

0.1920.1920.212

13/417/82

17/8221/8

35/837/841/8

555

0.2120.2120.212

BS 3410:1961

10 © BSI 02-2000

Table 8 — Large black washers

1 2 3 4

Nominal size of bolt Diameter of hole A Tolerance + 1/32 in

Outside diameter B

Thickness CTolerance ± 1 gauge

in in in S.W.G. in

1/45/163/8

9/3211/3213/32

3/47/8

1

121212

0.1040.1040.104

7/161/29/16

15/329/165/8

11/811/413/8

121210

0.1040.1040.128

5/83/47/8

11/1613/1615/16

11/213/42

1098

0.1280.1440.160

111/811/4

11/16

13/16

13/8

21/421/223/4

776

0.1760.1760.192

13/811/215/8

11/215/813/4

331/431/2

665

0.1920.1920.212

13/417/82

17/8221/8

33/4441/4

555

0.2120.2120.212

BS 3410:1961

© BSI 02-2000 11

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

Thickness CTolerance ± 1 gauge

in in in S.W.G. in

1/45/163/8

9/3211/3213/32

9/165/83/4

161616

0.0640.0640.064

7/161/29/16

15/3217/3219/32

7/8111/8

161614

0.0640.0640.080

5/83/47/8

21/3225/3229/32

11/411/215/8

141414

0.0800.0800.080

111/811/4

11/32

15/32

19/32

17/821/823/8

141414

0.0800.0800.080

13/811/2

113/32

117/32

25/827/8

1414

0.0800.080

BS 3410:1961

12 © BSI 02-2000

Table 10 — Round black washers with square holes for woodwork and timber constructions

1 2 3 4

Nominal size of bolt Width of hole A Tolerance + 1/32 in

Outside diameter B

Thickness CTolerance ± 1 gauge

in in in S.W.G. in

3/81/25/8

7/169/1611/16

11/411/22

11109

0.1160.1280.144

3/47/8

1

13/1615/16

11/16

21/425/83

855

0.1600.2120.212

BS 3410:1961

© BSI 02-2000 13

Table 11 — Square black washers with round holes

1 2 3 4

Nominal size of bolt Diameter of hole A Tolerance + 1/32 in

Outside square B

Thickness C Tolerance ± 1 gauge

in in in S.W.G. in

3/8 7/16

11/210 0.128

2

1/2 9/16

11/2 10 0.1282

5/8 11/16

2 10 0.128

36 0.192

3 0.252

3/4 13/16

21/2 10 0.128

3 6 0.192

33 0.252

4

7/8 15/16

21/2 10 0.128

3 3 0.252

1 11/16

33 0.252

4

4 3/0 0.372

11/4 13/8 43 0.252

3/0 0.372

BS 3410:1961

14 © BSI 02-2000

Table 12 — Square or D-shaped taper washers

1 2 3 4

Nominal size of bolt

Diameter of hole†A Overall size

B

Mean thicknessC

Tolerance + 1/32 in 3° and 5° 8°

in in in in in

3/81/25/8

7/169/1611/16

111/411/2

3/163/163/16

1/41/41/4

3/47/8

1

13/1615/16

11/16

13/4221/4

3/163/163/16

1/41/41/4

* Angle of taper may be 3°, 5° or 8°.† Centre hole to be parallel to within 4°.

blank

BS 3410:1961

BSI389 Chiswick High RoadLondonW4 4AL

BSI — British Standards InstitutionBSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter.

Revisions

British Standards are updated by amendment or revision. Users of British Standards should make sure that they possess the latest amendments or editions.

It is the constant aim of BSI to improve the quality of our products and services. We would be grateful if anyone finding an inaccuracy or ambiguity while using this British Standard would inform the Secretary of the technical committee responsible, the identity of which can be found on the inside front cover. Tel: 020 8996 9000. Fax: 020 8996 7400.

BSI offers members an individual updating service called PLUS which ensures that subscribers automatically receive the latest editions of standards.

Buying standards

Orders for all BSI, international and foreign standards publications should be addressed to Customer Services. Tel: 020 8996 9001. Fax: 020 8996 7001.

In response to orders for international standards, it is BSI policy to supply the BSI implementation of those that have been published as British Standards, unless otherwise requested.

Information on standards

BSI provides a wide range of information on national, European and international standards through its Library and its Technical Help to Exporters Service. Various BSI electronic information services are also available which give details on all its products and services. Contact the Information Centre. Tel: 020 8996 7111. Fax: 020 8996 7048.

Subscribing members of BSI are kept up to date with standards developments and receive substantial discounts on the purchase price of standards. For details of these and other benefits contact Membership Administration. Tel: 020 8996 7002. Fax: 020 8996 7001.

Copyright

Copyright subsists in all BSI publications. BSI also holds the copyright, in the UK, of the publications of the international standardization bodies. Except as permitted under the Copyright, Designs and Patents Act 1988 no extract may be reproduced, stored in a retrieval system or transmitted in any form or by any means – electronic, photocopying, recording or otherwise – without prior written permission from BSI.

This does not preclude the free use, in the course of implementing the standard, of necessary details such as symbols, and size, type or grade designations. If these details are to be used for any other purpose than implementation then the prior written permission of BSI must be obtained.

If permission is granted, the terms may include royalty payments or a licensing agreement. Details and advice can be obtained from the Copyright Manager. Tel: 020 8996 7070.