Bsi bs 4a 111 1993 (1999)

BRITISH STANDARD

BS 4A
1 1 1 :1 993
(superseding
BS 3A 1 11 :1 962)

Specification for

Cadmium-plated steel
bolts —
(Unified hexagons and
Unified threads) with
close tolerance shanks

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BS 4A 111:1993

Committees responsible for this
British Standard
The preparation of this British Standard was entrusted by the Aerospace
Systems Standards Policy Committee (ACE/- ) to Technical Committee ACE/1 2,
upon which the following bodies were represented:
The Association of Electronics, Telecommunications and Business Equipment
Industries
British Industrial Fasteners Federation
Ministry of Defence
Society of British Aerospace Companies Ltd.

This British Standard, having
been prepared under the
direction of the Aerospace
Standards Policy Committee,
was published under the
authority of the Standards
Board and comes
into effect on
1 5 April 1 993
© BSI 1 2- 1 999

The following BSI references
relate to the work on this
standard:
Committee reference ACE/1 2
Draft announced in

BSI News February 1 993

ISBN 0 580 21647 0

Reprodu ced by I H S u n d er l i cen se wi th BSI - U n con trol l ed Copy

Amendments issued since publication
Amd. No.

Date

Comments

BS 4A 111:1993

Contents
Page
C ommittees res p ons ib le

Ins ide front cover

Foreword

ii

1

S cop e

1

2

References

1

3

Procurement

1

4

Materials and manufacture

1

5

Anti- corros ion treatment

1

6

D imens ions

1

7

S crew threads

1

Tab le 1 — D imens ions
Tab le 2 — Bearing length
overall length

E

Lis t of references

© BS I 1 2 - 1 99 9
Reprodu ced by I H S u n d er l i cen se wi th BSI - U n con trol l ed Copy

L

, clamp ing length

M

2
and
3
Ins ide b ack cover

i


BS 4 A 1 1 1 : 1 993

Fore word

This edition of this British Standard has been prepared under the direction of the
Aerospace Standards Policy Committee and supersedes BS 3A 1 1 1 : 1 962 which is
withdrawn.
This edition clarifies the maximum diameter of bolts after plating, but it does not
reflect a full review or revision of the standard which will be undertaken in due
course. The 0. 0003 in plating allowance on the maximum diameter quoted in

BS 3A 1 1 1 (and preceding editions) is now embodied in the maximum diameter
after plating in Table 1 , and separate reference to a plating allowance has been
deleted. The maximum diameter of bolts before plating has been deleted and the
thickness of plating is now controlled.
An equivalent range of bolts with unplated shanks is specified in BS 3A 1 08.
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.
C omp liance with a British S tand ard d oe s no t of itse lf confe r immunity
from le gal ob ligatio ns.

S ummary of p age s

This document comprises a front cover, an inside front cover, pages i and ii,
pages 1 to 4, an inside back cover 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.

ii
Reprodu ced by I H S u n d er l i cen se wi th BSI - U n con trol l ed Copy

© BSI 1 2- 1 999


BS 4A 1 1 1 :1 993

4.2 In the finally heat-treated condition, the
mechanical
properties of the material used for
This British Standard specifies the materials,

forged
bolts
shall be as follows:
dimensions, finish and inspection requirements for
0.1 % proof stress
not less than
steel bolts with Unified hexagons, Unified threads
664 MPa
and close tolerance shanks cadmium plated to be
(43 tonf/in2)
suitable for insertion in aluminium alloy materials,
for aircraft.
tensile strength
not less than
850 MPa
2 References
(55 tonf/in2)
not more than
2.1 Normative references
1 003 MPa
This British Standard incorporates, by reference,
(65 tonf/in2)
provisions from specific editions of other
publications. These normative references are cited
elongation on 4 Ỉ area
not less than 18 %
at the appropriate points in the text and the
Izod impact value:
not less than 54 J
publications are listed on the inside back cover.

(40 ft·lbf)
Subsequent amendments to, or revisions of, any of
these publications apply to this standard only when 5 Anti-corrosion treatment
incorporated in it by updating or revision.
All finished bolts shall be coated with cadmium in
2.2 Informative references
This British Standard refers to other publications accordance with DEF STAN 03-19[1].
that provide information or guidance. Editions of 6 Dimensions
these publications current at the time of issue of this
6.1 All finished bolts, after the application of the
standard are listed on the inside back cover, but
cadmium coating, shall conform to the dimensions
reference should be made to the latest editions.
and tolerances given in Table 1 and Table 2.
3 Procurement
6.2 The clamping length of the bolt shall conform to
the dimensions and tolerances given in Table 2, and
The bolts shall conform to the latest edition of
shall
be such that when a standard nut without
BS A 100.
countersink or ring gauge without countersink has
been screwed on as far as possible by hand, its
4 Materials and manufacture
leading face is within the distance M from the
4.1 The bolts shall be manufactured by one of the
underside of the bolt head. The runout of thread
following methods:
shall not exceed twice the pitch.
a) machined from bright drawn bars which

6.3 The nominal length of the bolt shall be the
conform to the following British Standards:
minimum bearing length L, which is determined by
the minimum clamping length M less two thread
BS 3S 95:1967
pitches.
or BS 2S 114:1964
or BS 2S 116:1964 bolts up to and
7 Screw threads
including 3/8 in diameter;
The bolts shall have Unified threads of the form and
or BS 2S 117:1964
class of fit specified in the latest edition of BS A 100.
or BS S 154:1976

1 Scope

NOTE BS S 96 material may be used until stocks are
exhausted.

b) forged from material which conforms to the
following British Standards:
BS 3S 102:1969
or BS 3S 105:1969
or BS 2S 147:1976
or BS S 148:1969
or BS 2S 149:1976
or BS S 158:1977

© BSI 12-1999

Reprodu ced by I H S u n d er l i cen se wi th BSI - U n con trol l ed Copy

1


2

2

/1 6

7

© BSI 1 2 - 1 999

4

5

6

, clamping length

0. 4987

0. 4362

0. 3737

0. 31 1 2

0. 2 489

0. 1 887

Min.

Before
plating

M

0. 4993

0. 4368

0. 3743

0. 31 1 8

0. 2 493

0. 1 891

Min.

E

7

M

0. 770

0. 670

0. 5 97

0. 497

0. 459

0. 377

9

0. 75 0

0. 688

0. 562

0. 500

0. 438

0. 344

Max.

E

0. 741

0. 679

0. 5 54

0. 493

0. 431

0. 866

0. 794

0. 65 0

0. 5 77

0. 5 05

0. 397

Max.

C

Width
across

corners

10

12

0. 300

0. 2 70

0. 2 2 0

0. 1 80

0. 1 50

0. 1 1 5

Max.

Min.

0. 2 90

0. 2 60

0. 2 1 0

0. 1 70

0. 1 40

0. 1 05

D

Thickness of
head

11

14

0. 030

0. 030

0. 030

0. 030

0. 030

0. 02 0

Max.

Min.

0. 01 5

0. 01 5

0. 01 5

0. 01 5

0. 01 5

0. 01 0

R

Radius under
bolt head

13

16

0. 050

0. 050

0. 040

0. 040

0. 040

0. 030

Max.

Min.

0. 040

0. 040

0. 030

0. 030

0. 030

0. 02 0

G

Depth of
chamfer

15

18

0. 74

0. 67

0. 5 5

0. 49

0. 43

0. 33

–0. 01

0

K

0. 03

0. 03

0. 03

0. 03

0. 03

0. 03

H

Diameter Depth

Identification
disk

17

D imensions in inches

. It is not intended for use for manufacturing or inspection purposes.

Min.

0. 339

B

Width across
flats

8

and minimum length

Reference
only

2)

F

Minimum
length of
screwed
portion of
shank

see Table 2 .

0. 1 00

0. 1 00

0. 083

0. 083

0. 071

0. 063

and overall length

0. 5 001

0. 4376

0. 3751

0. 31 2 6

0. 2 5 01

0. 1 899

Max.

After plating

A

Diameter of plain portion
2 × pitch
of shank

3

This dimension is an absolute minimum associated with maximum length

L

/2 in UNF

/1 6 in UNF

/8 in UNF

/1 6 in UNF

For b earing length

1

7

3

5

Reprodu ced by I H S u n d er l i cen se wi th BSI - U n con trol l ed Copy

2)

1)

/2

/8

3

1

/1 6

5

/4 in UNF

1

1

/4

No. 1 0- 32 UNF

0. 1 90

Thread

Nominal size

Diameter
of plain
portion
of shank

1

Table 1 — Dimensions

BS 4A 111:1993


BS 4A 1 1 1 : 1 993

Tab le 2 — Be aring le ngth

L

, clamping le ngth

M

and ove rall le ngth

E
Dimensions in inches

1

No . 1 0 -3 2 UNF

Part No.

0
La min. M –0.03
E

+0.04
0

Part No.

5

/4 in UNF

0
La min. M –0.03

E

+0.04
0

Part No.

/1 6 in UNF

0
La min. M –0.03
E

+0.04
0

/2 D
1D
2D
3D
4D
5D

0.05
0.1
0.2
0.3
0.4
0.5

0.143
0.193
0.293
0.393
0.493
0.593

0.55
0.60
0.70
0.80
0.90
1.00

1E
2E
3E
4E
5E

0.1
0.2
0.3
0.4
0.5

0.201
0.301
0.401
0.501

0.601

0.70
0.80
0.90
1.00
1.10

1G
2G
3G
4G
5G

0.1
0.2
0.3
0.4
0.5

0.213
0.313
0.413
0.513
0.613

0.75
0.85
0.95
1.05

1.15

6D
7D
8D
9D
10D

0.6
0.7
0.8
0.9
1.0

0.693
0.793
0.893
0.993
1.093

1.10
1.20
1.30
1.40
1.50

6E
7E
8E
9E

10E

0.6
0.7
0.8
0.9
1.0

0.701
0.801
0.901
1.001
1.101

1.20
1.30
1.40
1.50
1.60

6G
7G
8G
9G
10G

0.6
0.7
0.8
0.9

1.0

0.713
0.813
0.913
1.013
1.113

1.25
1.35
1.45
1.55
1.65

11D
12D
13D
14D
15D

1.1
1.2
1.3
1.4
1.5

1.193
1.293
1.393
1.493

1.593

1.60
1.70
1.80
1.90
2.00

11E
12E
13E
14E
15E

1.1
1.2
1.3
1.4
1.5

1.201
1.301
1.401
1.501
1.601

1.70
1.80
1.90
2.00

2.10

11G
12G
13G
14G
15G

1.1
1.2
1.3
1.4
1.5

1.213
1.313
1.413
1.513
1.613

1.75
1.85
1.95
2.05
2.15

16D
17D
18D
19D

20D

1.6
1.7
1.8
1.9
2.0

1.693
1.793
1.893
1.993
2.093

2.10
2.20
2.30
2.40
2.50

16E
17E
18E
19E
20E

1.6
1.7
1.8
1.9

2.0

1.701
1.801
1.901
2.001
2.101

2.20
2.30
2.40
2.50
2.60

16G
17G
18G
19G
20G

1.6
1.7
1.8
1.9
2.0

1.713
1.813
1.913
2.013

2.113

2.25
2.35
2.45
2.55
2.65

21D

2.1

2.193

2.60

21E

2.1

2.201

2.70

21G

2.1

2.213

2.75

22D
23D
24D

2.2
2.3
2.4

2.293
2.393
2.493

2.70
2.80
2.90

22E
23E
24E

2.2
2.3
2.4

2.301
2.401
2.501

2.80
2.90
3.00

22G
23G
24G

2.2
2.3
2.4

2.313
2.413
2.513

2.85
2.95
3.05

25D

2.5

2.593

3.00

25E
26E

27E

2.5
2.6
2.7

2.601
2.701
2.801

3.10
3.20
3.30

25G
26G
27G

2.5
2.6
2.7

2.613
2.713
2.813

3.15
3.25
3.35

28E
29E
30E

2.8
2.9
3.0

2.901
3.001
3.101

3.40
3.50
3.60

28G
29G
30G

2.8
2.9
3.0

2.913
3.013
3.113

3.45
3.55

3.65

31G
32G
33G
35G

3.1
3.2
3.3
3.4
3.5

3.213
3.313
3.413
3.513
3.613

3.75
3.85
3.95
4.05
4.15

36G
37G

3.6
3.7

3.713
3.813

4.25
4.35

1

NOTE Bolts below the heavy line may not be readily available in large quantities because of limitations in manufacture by forging.
6. 3 .

a See

© BSI 12-1999
Reprodu ced by I H S u n d er l i cen se wi th BSI - U n con trol l ed Copy

3


BS 4 A 1 1 1 :1 993

Tab le 2 — Be aring length
3

Part No.

L

, clamp ing le ngth

7

/8 in UNF

Lb min. M

0
–0.03

E

+0.04
0

Part No.

M

and ove rall length
1

/1 6 in UNF

Lb min. M

0
–0.03

E

+0.04
0

Part No .

E

/2 in UNF

Lb min. M

0
–0.03

E +0.04
0

1J
2J
3J
4J
5J

0.1
0.2
0.3
0.4
0.5

0.213

0.313
0.413
0.513
0.613

0.85
0.95
1.05
1.15
1.25

1L
2L
3L
4L
5L

0.1
0.2
0.3
0.4
0.5

0.230
0.330
0.430
0.530
0.630

0.95

1.05
1.15
1.25
1.35

1N
2N
3N
4N
5N

0.1
0.2
0.3
0.4
0.5

0.230
0.330
0.430
0.530
0.630

1.05
1.15
1.25
1.35
1.45

6J

7J
8J
9J
10J

0.6
0.7
0.8
0.9
1.0

0.713
0.813
0.913
1.013
1.113

1.35
1.45
1.55
1.65
1.75

6L
7L
8L
9L
10L

0.6

0.7
0.8
0.9
1.0

0.730
0.830
0.930
1.030
1.130

1.45
1.55
1.65
1.75
1.85

6N
7N
8N
9N
10N

0.6
0.7
0.8
0.9
1.0

0.730

0.830
0.930
1.030
1.130

1.55
1.65
1.75
1.85
1.95

11J
12J
13J
14J
15J

1.1
1.2
1.3
1.4
1.5

1.213
1.313
1.413
1.513
1.613

1.85

1.95
2.05
2.15
2.25

11L
12L
13L
14L
15L

1.1
1.2
1.3
1.4
1.5

1.230
1.330
1.430
1.530
1.630

1.95
2.05
2.15
2.25
2.35

11N

12N
13N
14N
15N

1.1
1.2
1.3
1.4
1.5

1.230
1.330
1.430
1.530
1.630

2.05
2.15
2.25
2.35
2.45

16J
17J
18J
19J
20J

1.6

1.7
1.8
1.9
2.0

1.713
1.813
1.913
2.013
2.113

2.35
2.45
2.55
2.65
2.75

16L
17L
18L
19L
20L

1.6
1.7
1.8
1.9
2.0

1.730

1.830
1.930
2.030
2.130

2.45
2.55
2.65
2.75
2.85

16N
17N
18N
19N
20N

1.6
1.7
1.8
1.9
2.0

1.730
1.830
1.930
2.030
2.130

2.55

2.65
2.75
2.85
2.95

21J
22J
23J
24J
25J
26J
27J
28J
29J
30J

2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.0

2.213
2.313
2.413

2.513
2.613
2.713
2.813
2.913
3.013
3.113

2.85
2.95
3.05
3.15
3.25
3.35
3.45
3.55
3.65
3.75

21L
22L
23L
24L
25L
26L
27L
28L
29L
30L

2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.0

2.230
2.330
2.430
2.530
2.630
2.730
2.830
2.930
3.030
3.130

2.95
3.05
3.15
3.25
3.35
3.45
3.55
3.65

3.75
3.85

21N
22N
23N
24N
25N
26N
27N
28N
29N
30N

2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.0

2.230
2.330
2.430
2.530
2.630

2.730
2.830
2.930
3.030
3.130

3.05
3.15
3.25
3.35
3.45
3.55
3.65
3.75
3.85
3.95

31J
32J
33J
34J
35J

3.1
3.2
3.3
3.4
3.5

3.213

3.313
3.413
3.513
3.613

3.85
3.95
4.05
4.15
4.25

31L
32L
33L
34L
35L

3.1
3.2
3.3
3.4
3.5

3.230
3.330
3.430
3.530
3.630

3.95

4.05
4.15
4.25
4.35

31N
32N
33N
34N
35N

3.1
3.2
3.3
3.4
3.5

3.230
3.330
3.430
3.530
3.630

4.05
4.15
4.25
4.35
4.45

36L

37L
38L
39L
40L

3.6
3.7
3.8
3.9
4.0

3.730
3.830
3.930
4.030
4.130

4.45
4.55
4.65
4.75
4.85

36N
37N
38N
39N
40N

3.6

3.7
3.8
3.9
4.0

3.730
3.830
3.930
4.030
4.130

4.55
4.65
4.75
4.85
4.95

41N
42N
43N
44N
45N

4.1
4.2
4.3
4.4
4.5

4.230

4.330
4.430
4.530
4.630

5.05
5.15
5.25
5.35
5.45

NOTE Bolts below the heavy line may not be readily available in large quantities because of limitations in manufacture by forging.
6. 3 .

b See

4
Reprodu ced by I H S u n d er l i cen se wi th BSI - U n con trol l ed Copy

© BSI 12-1999


BS 4A 111:1993

List of references

(see clause 2)

Normative references
BSI standards publications

BRITISH STANDARDS INSTITUTION, London

Specification for general requirements for bolts and free running nuts of tensile strength
not exceeding 1 249 MPa .
BS 3S 95: 1 967, Specification for 1 1 /2 per cent nickel-chromium-molybdenum
steel [90/110 kgf/mm2 (57/70 tonf/in2): limiting ruling section 150 mm (6 in)].
BS 3S 1 02: 1 969, Specification for carbon-molybdenum steel (bar for the manufacture of forged bolts only).
BS 3S 1 05: 1 969, Specification for carbon steel (bar for the manufacture of forged bolts only).
BS 2S 1 1 4: 1 964, Specification for aircraft material. Manganese-molybdenum steel (55/65 tonf/sq in: limiting
ruling section 21 /2 inches).
BS 2S 1 1 6: 1 964, Specification for aircraft material “40” carbon steel bright bars for
machining (55-65 tonf/sq in: limiting ruling section 3/4 inch) (primarily intended for the manufacture of
machined bolts).
BS 2S 1 1 7: 1 964, Specification for aircraft material. 1 per cent chromium steel (55/65 tonf/sq in: limiting
ruling section 1 1 /8 inch).
BS 2S 1 47: 1 976, Specification for 0.5 % nickel-chromium-molybdenum steel bars for the manufacture of
forged bolts and forged nuts.
BS S 1 48: 1 969, Specification for low nickel-chromium steel (bar for the manufacture of forged bolts only).
BS 2S 1 49: 1 976, Specification for 1.75 % nickel-chromium-molybdenum steel bars for the manufacture of
forged bolts and forged nuts.
BS S 1 54: 1 976, Specification. 21 2 % nickel-chromium-molybdenum steel billets, bars, forgings and
parts (880–1 080 MPa: limiting ruling section 150 mm).
BS S 1 58: 1 977, Specification for 1 % chromium-molybdenum steel bars for the manufacture of forged bolts
and forged nuts.

BS 3A 1 00: 1 991 ,

1)

Other references

[1 ] DEF STAN 03- 1 9

Electro-Deposition of Cadmium available from Ministry of Defence (Procurement

Executive), Directorate of Standardization, Kentigern House, 65 Brown St, Glasgow G2 8EX.

Informative references
BSI standards publications
BRITISH STANDARDS INSTITUTION, London

Specification for steel bolts (Unified hexagons and Unified threads) with close tolerance
shanks for aircraft .
BS 2S 96: 1 964, Specification for 21 /2 per cent nickel-chromium-molybdenum steel (55/65 tonf/sq in: limiting
ruling section 6 in) .

BS 3A 1 08: 1 962,

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Edition current at time of publication (see clauses
Referred to in the foreword only.
Withdrawn.

© BSI 1 2- 1 999

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BS 4A
111:1993

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