BS 3410 1961 Washers

BS 3410:1961

BRITISH STANDARD OBSOLESCENT MAY 1986

Specification for

Metal washers — For general engineering purposes

UDC 621.882.4

BS 3410 3410:19 :1961 61

Co-operating organizations 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:  Admiralty*  Air Ministry  Associated Offices’ Technical Committee  Association of Consulting Engineers (Incorporated) Brit Britis ish h Chem hemical ical Pla Plant Manu Manufa fact ctur urer ers’ s’  Association British Compressed Air Society Britis British h Electr Electrica icall and Allied Allied Manufa Manufactu cturer rers’ s’  Association* British Engineers’ Association* Brit Britis ish h Gea Gearr Man Manuf ufac actu ture rers rs’’ Ass Assoc ocia iati tion on Briti sh sh Internal Combustion Engi ne ne Manufacturers’ Association* British Ir Iron an and St Steel Fe Federation* Brit Britis ish h Rai Railw lway ays, s, The The Bri Briti tish sh Tran Transp spor ortt Commission* Crow Crown n Age Agent ntss for for Ove Overs rsea ea Gov Gover ernm nmen ents ts and and  Administrations* D.S. D.S.I. I.R. R. — Nati Nationa onall Engi Engine neer erin ing g Labo Labora rato tory ry Electricity Electricity Council, Council, The The Generati Generating ng Board Board and the the Area Area Boar Boards ds in Engl Englan and d and and Wale Waless Engi Engine neer erin ing g Equ Equip ipme ment nt User Users’ s’ Ass Assoc ocia iati tion on* *

Gas Council High Commission of India* Institute of Marine Engineers Institute of Petroleum Institution of Civil Engineers Insti nstitu tuti tion on of Gas Gas Eng Enginee ineers rs Institution of Heating and Ventilating Engineers Instit Instituti ution on of Mechan Mechanica icall Enginee Engineers rs Institution of Mechanical Engineers (Automobile Division) Inst Instit itut utio ion n of of Pro Produ duct ctio ion n Eng Engin inee eers rs* * Loco mo mo ti tive and Allie d Manufacture rrss’ Association of Great Britain* Machine To Tool Tr Trades As Association* Mini Minist stry ry of Labo Labour ur (Fac (Facto tory ry Insp Inspec ecto tora rate te)) Ministry of Power Mini Minist stry ry of Tra Trans nspo port rt Ministry of Works Nati Nation onal al Coa Coall Boar Board d National National Physical Physical Labora Laboratory tory (D.S.I.R.)* (D.S.I.R.)* Radi Radio o Indu Indust stry ry Coun Counci cil* l* War War Off Offic ice* e*

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:  Agricultural Engineers’ Association Blac Black k Bol Boltt & Nut Nut Asso Associ ciat atio ion n of of Gre Great at Brit Britai ain n Bright Bright Bolt Bolt & Nut Manufa Manufactu cturers rers’’ Assoc Associat iation ion Bright Steel Bar Association Brit British ish Const Constru ruct ctio iona nall Stee Steelw lwor ork k Asso Associ ciat atio ion n Brit Britis ish h Cycle ycle & Mot Motor Cyc Cycle Ind Industr ustrie iess  Association Limited Council Council of British British Manufac Manufacturers turers of Petroleum Petroleum Equipment Electronic En Engineering Association Heat Treated Bolt Association Institute of Iron & Steel Wire Manufacturers

This British Standard, having been approved by the Mechanical Mechanical Engineering Engineering Industry Industry Standards Standards Committee Committee and endorsed by the Chairman of the Engineering Engineering Divisional Divisional Council, was published under the authority authority of the General Council on 1 Septem September ber 1961 1961

 Amendments issued since publication publication

© BSI 02-2000

 Amd. No. The following BSI references relate to the work on this standard: Committee references MEE/60 MEE/60/6 Draft for comment A(MEE)4400

ISBN 0 580 34594 7

London Transport Executive, The British Tran Transp spor ortt Com Commi miss ssio ion n Minist Ministry ry of of Aviat Aviation ion Oil Companies Materials Association Post Post Off Offic ice e Rolle olled d Threa hread d Scre Screw w Assoc ssocia iati tion on Screw Manufacturers’ Association Society Society of Motor Manufacturer Manufacturerss & Traders Traders Limited Washer Manufacturers’ As Association Individual firms

Date

Comments

BS 3410:1961

Contents

Co-operating organizations Foreword Part 1: Bright metal washers 1 Scope 2 Material 3 Finish 4 Coating 5 Dimensions

1 1 1 1 1

Part 2: Black metal washers 6 Scope 7 Material 8 Finish 9 Dimensions

8 8 8 8

Table 1 — Small bright washers for use with B.A. and  American Number size fasteners Table 2 — Large bright washers for use with B.A. and  American Number size fasteners Table 3 — Small bright washers for use with UNC, UNF, B.S.W and B.S.F fasteners Table 4 — Large bright washers for use with UNC, UNF, B.S.W. and B.S.F. fasteners Table 5 — Medium bright washers for automobile purposes for use with UNC, UNF, B.S.W and B.S.F. fasteners Table 6 — Large bright washers for automobile purposes for use with UNC, UNF, B.S.W. and B.S.F. fasteners Table 7 — Ordinary black washers Table 8 — Large black washers Table 9 — Small light gauge black washers Table 10 — Round black washers with square holes for woodwork and timber constructions Table 11 — Square black washers with round holes Table 12 — Square or D-shaped taper washers

© BSI 02-2000

Page Inside front cover ii

2 3 4 5 6 7 9 10 11 12 13 14

i

BS 3410:1961

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 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”. 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”.

ii

© BSI 02-2000

BS 3410:1961

Part 1: Bright metal washers 1 Scope

3 Finish

Part 1 of this British Standard relates to bright metal washers for use with standard fasteners and for other general purposes.

The washers shall be reasonably flat and free from burrs. Standard washers will normally be supplied unchamfered.

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.

If chamfered washers are required this should be specified by the purchaser in his enquiry or order.

General requirements for material and finish of bright washers are also given.

5 Dimensions

2 Material

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.

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

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.

© BSI 02-2000

1

BS 3410:1961

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

3

see Clause 1 B.A. No.

2  American No. size

3

4

5

Diameter of hole

Outside diameter

 A

 B

6 Thicknessa C 

max.

min.

max.

min.

in

in

in

in

S.W.G.

in

8

2

0.099

0.094

0.185

0.180

25

0.020

7

3

0.111

0.106

0.208

0.203

24

0.022

6

4

0.123

0.118

0.233

0.228

23

0.024

5

5

0.140

0.135

0.268

0.263

23

0.024

4

6

0.157

0.152

0.301

0.296

22

0.028

3

8

0.177

0.172

0.341

0.336

22

0.028

2

10

0.202

0.197

0.391

0.386

21

0.032

1

12

0.228

0.223

0.443

0.438

20

0.036

0

 — 

0.256

0.251

0.500

0.495

19

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”. a Subject to the normal manufacturing tolerances on the sheet or strip as specified in the appropriate British Standards.

2

© BSI 02-2000

BS 3410:1961

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

see Clause 1 B.A.

2  American No. size

3

3

4

5

Diameter of hole

Outside diameter

 A

 B

6 Thicknessa C 

max.

min.

max.

min.

in

in

in

in

S.W.G.

in

14

 — 

0.049

0.044

0.097

0.092

27

0.016

12

 — 

0.061

0.056

0.130

0.125

27

0.016

10

0

0.078

0.073

0.176

0.171

27

0.016

9

1

0.086

0.081

0.197

0.192

27

0.016

8

2

0.099

0.094

0.228

0.223

25

0.020

7

3

0.111

0.106

0.257

0.252

22

0.028

6

4

0.123

0.118

0.288

0.283

20

0.036

5

5

0.140

0.135

0.335

0.330

20

0.036

4

6

0.157

0.152

0.378

0.373

19

0.040

3

8

0.177

0.172

0.432

0.427

19

0.040

2

10

0.202

0.197

0.500

0.495

18

0.348

1

12

0.228

0.223

0.565

0.560

18

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”. a Subject to the normal manufacturing tolerances on the sheet or strip as specified in the appropriate British Standards.

© BSI 02-2000

3

BS 3410:1961

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

see Clause 1

2

3

4

5

3

6

Diameter of hole

Outside diameter

 A

 B

Nominal size of bolt or screw

max.

min.

max.

min.

in

in

in

in

in

7 a

Thickness C 

Heavy gauge S.W.G.

Light gauge

in

S.W.G.

in

1

0.270

0.265

0.562

0.557

17

0.056

20

0.036

5

0.333

0.328

0.625

0.620

15

0.072

19

0.040

3

0.395

0.390

0.750

0.745

15

0.072

18

0.048

7

0.458

0.453

0.875

0.870

13

0.092

18

0.048

1/ 2

0.520

0.515

1.000

0.995

13

0.092

17

0.056

9/ 16

0.593

0.588

1.125

1.115

12

0.104

17

0.056

5

0.656

0.651

1.250

1.240

11

0.116

15

0.072

3

0.781

0.776

1.500

1.490

10

0.128

15

0.072

7

0.906

0.901

1.625

1.615

9

0.144

15

0.072

1.031

1.026

1.875

1.865

8

0.160

15

0.072

1 /8 11/4

1.156

1.151

2.125

2.115

7

0.176

13

0.092

1.281

1.276

2.375

2.355

7

0.176

11

0.116

13/8 11/2 13/4

1.406

1.401

2.625

2.605

6

0.192

 — 

 — 

1.531

1.526

2.875

2.855

6

0.192

 — 

 — 

1.781

1.776

3.375

3.345

5

0.212

 — 

 — 

2

2.031

2.026

3.625

3.595

5

0.212

—

—

/4 /16 /8 /16

/8 /4 /8

1 1

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 3

/32 1 /8 5 /32

4

use B.A. size

7 5 3

For inch size 3

/16 /32

7

use B.A. size

2 1

© BSI 02-2000

BS 3410:1961

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

see Clause 1

2

3

4

5

3

6

Diameter of hole

Outside diameter

 A

 B

Nominal size of bolt or screw

max.

min.

max.

min.

in

in

in

in

in

7 a

Thickness C 

Heavy gauge S.W.G.

Light gauge

in

S.W.G.

in

1

/4

0.270

0.265

0.625

0.620

17

0.056

19

0.040

5

/16

0.333

0.328

0.750

0.745

15

0.072

18

0.048

3

/8

0.395

0.390

0.875

0.870

15

0.072

18

0.048

7

/16

0.458

0.453

1.000

0.995

13

0.092

17

0.056

1

/2

0.520

0.515

1.125

1.115

13

0.092

17

0.056

9/ 16

0.593

0.588

1.250

1.240

12

0.104

17

0.056

5

/8

0.656

0.651

1.375

1.365

11

0.116

15

0.072

3

/4

0.781

0.776

1.625

1.615

10

0.128

15

0.072

7

/8

0.906

0.901

1.875

1.865

9

0.144

15

0.072

1

1.031

1.026

2.125

2.115

8

0.160

13

0.092

11/8 11/4

1.156

1.151

2.375

2.355

7

0.176

12

0.104

1.281

1.276

2.625

2.605

7

0.176

11

0.116

13/8 11/2 13/4

1.406

1.401

2.875

2.855

6

0.192

10

0.128

1.531

1.526

3.125

3.095

6

0.192

10

0.128

1.781

1.776

3.625

3.595

5

0.212

10

0.128

2

2.031

2.026

4.125

4.095

5

0.212

10

0.128

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 2, are suitable. For inch size 1

/16 3 /32 1 /8

© BSI 02-2000

use B.A. size

10 7 5

For inch size 5

/32 /16 7 /32 3

use B.A. size

3 2 1

5

BS 3410:1961

Table 5 — Medium bright washers for automobile purposes for use with UNC, UNF, B.S.W. and B.S.F. fasteners

1

4

5

Diameter of hole

Outside diameter

 A

 B

max.

min.

max.

min.

in

in

in

in

in

6 Thicknessa C 

S.W.G.

in

1

0.270

0.265

0.750

0.745

16

0.064

5

0.333

0.328

0.875

0.870

15

0.072

3

0.395

0.390

1.000

0.995

14

0.080

7

0.458

0.453

1.125

1.115

13

0.092

1

0.520

0.515

1.250

1.240

12

0.104

9

0.593

0.588

1.375

1.365

11

0.116

5

0.656

0.651

1.625

1.615

10

0.128

3

0.781

0.776

1.875

1.865

9

0.144

7

0.906

0.901

2.125

2.115

8

0.160

1.031

1.026

2.375

2.355

6

0.192

/16 /8 /16 /2 /16 /8 /4 /8

1

6

3

Nominal size of bolt or screw

/4

a

2

Subject to the normal manufacturing tolerances on the sheet or strip as specified in the appropriate British Standards.

© BSI 02-2000

BS 3410:1961

Table 6 — Large bright washers for automobile purposes for use with UNC, UNF, B.S.W. and B.S.F. fasteners

1 Nominal size of bolt or screw

2

4

5

Diameter of hole

Outside diameter

 A

 B

6 Thicknessa C 

max.

min.

max.

min.

in

in

in

in

in

S.W.G.

in

1

/4

0.270

0.265

1.000

0.995

16

0.064

5

/16

0.333

0.328

1.250

1.240

14

0.080

3

/8

0.395

0.390

1.375

1.365

13

0.092

7

/16

0.458

0.453

1.500

1.490

12

0.104

1

/2

0.520

0.515

1.625

1.615

11

0.116

9

/16

0.593

0.588

1.750

1.740

10

0.128

5

/8

0.656

0.651

2.000

1.990

10

0.128

3

/4

0.781

0.776

2.250

2.240

9

0.144

7

/8

0.906

0.901

2.500

2.480

8

0.160

1.031

1.026

2.750

2.730

6

0.192

1 a

3

Subject to the normal manufacturing tolerances on the sheet or strip as specified in the appropriate British Standards.

© BSI 02-2000

7

BS 3410:1961

Part 2: Black metal washers 6 Scope

8 Finish

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.

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

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.

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.

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

© BSI 02-2000

BS 3410:1961

Table 7 — Ordinary black washers

1

2

3

4

Nominal size of bolt

Diameter of hole  A Tolerance + 1 / 32 in

Outside diameter

Thickness C  Tolerance ± 1 gauge

in

in

in

1

/4

9

5

/16

3

 B

S.W.G.

in

5

16

0.064

11

3

14

0.080

/8

13

7

14

0.080

7

/16

15

1

12

0.104

1

/2

9

12

0.104

/16

5

11/8 11/4

10

0.128

10

0.128

9

0.144

8

0.160

9

/32 /32 /32 /32

/16 /8

/8 /4 /8

5/ 8

11/ 16

3

/4

13

7

/8

15

13/8 15/8 17/8 21/8 23/8 25/8

7

0.176

1 /8 11/4

11/16 13/16 13/8

7

0.176

6

0.192

13/8 11/2 15/8

11/2 15/8 13/4

27/8 31/8 33/8

6

0.192

6

0.192

5

0.212

13/4

17/8

35/8

5

0.212

7

1 1

7

/16 /16

1 /8

2

3 /8

5

0.212

2

21/8

41/8

5

0.212

© BSI 02-2000

9

BS 3410:1961

Table 8 — Large black washers

1

2

3

4

Nominal size of bolt

Diameter of hole  A Tolerance + 1 / 32 in

Outside diameter

Thickness C  Tolerance ± 1 gauge

in

 B

in

1

9

5

11

3

13

7/ 16

15/ 32

1

9

9

5

in

S.W.G.

in

3

12

0.104

7

12

0.104

1

12

0.104

11/8

12

0.104

/16

1

1 /4

12

0.104

/8

13/8

10

0.128

5/ 8

11/ 16

11/2

10

0.128

3

13

3

1 /4

9

0.144

7

15

2

8

0.160

21/4

/4 /16 /8 /2 /16 /4 /8

1

/32 /32 /32

/16 /16

11/16

/4 /8

7

0.176

1

1 /8

3

1 /16

1

2 /2

7

0.176

11/4

13/8

23/4

6

0.192

13/8

11/2

3

6

0.192

11/2

15/8

31/4

6

0.192

5

1 /8

3

1 /4

1

3 /2

5

0.212

13/4

17/8

33/4

5

0.212

17/8

2

4

5

0.212

5

0.212

2

10

1

2 /8

1

4 /4

© BSI 02-2000

BS 3410:1961

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

Thickness C  Tolerance ± 1 gauge

in

in

in

1

 B

S.W.G.

in

/4

9

9

16

0.064

5

/16

11

5

16

0.064

3

/8

13

3

16

0.064

7

/16

15

7

16

0.064

1

/2

17

1

16

0.064

9

/16

19

11/8

14

0.080

5

/8

21

11/4

14

0.080

3

/4

25

1

1 /2

14

0.080

7

/8

29

/32

15/8

14

0.080

1

11/32

17/8

14

0.080

11/8

15/32

21/8

14

0.080

3

/32 /32 /32 /32 /32 /32 /32 /32

/8 /4 /8

1

1 /4

1 /32

2 /8

14

0.080

13/8

113/32

25/8

14

0.080

11/2

117/32

27/8

14

0.080

© BSI 02-2000

9

/16

11

BS 3410:1961

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

Thickness C  Tolerance ± 1 gauge

in

in

3

7

1

9

5

11

3/ 4

13/ 16

7

15

/8 /2 /8 /8

1

12

 B

in

S.W.G.

in

/16

1

1 /4

11

0.116

/16

11/2

10

0.128

2

9

0.144

21/4

8

0.160

5

2 /8

5

0.212

3

5

0.212

/16 /16

11/16

© BSI 02-2000

BS 3410:1961

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

Thickness C  Tolerance ± 1 gauge

in

in

in

3

1

/8

7

/2

9

/16 /16

 B

11/2 2 11/2 2 2

5

/8

11

/16

3 21/2

3

/4

13

/16

3 3 4

7/ 8

15/ 16

21/2 3 3

1

11/16

4 4

11/4

© BSI 02-2000

13/8

4

S.W.G.

in

10

0.128

10

0.128

10

0.128

6

0.192

3

0.252

10

0.128

6

0.192

3

0.252

10

0.128

3

0.252

3

0.252

3/0

0.372

3

0.252

3/0

0.372

13

BS 3410:1961

Table 12 — Square or D-shaped taper washers

1

2

3

4

Diameter of hole>

Mean thickness Overall size

 A

Nominal size of bolt

C 

 B

Tolerance + 1 / 32 in in

in

in

3° and 5°

8°

in

in

3

7

1

3

/16

1

1

9

11/4

3

/16

1

5

11

1

1 /2

3

/16

1

3

13

13/4

3

/16

1

7

15

2

3

/16

1

/16

1

/8 /2 /8 /4 /8

1

/16 /16 /16 /16 /16

1

1 /16

1

2 /4

3

/4 /4 /4 /4 /4 /4

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

14

© BSI 02-2000

blank

BS 3410:1961

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