Bsi bs a 313 1997 (iso 12261 1996)

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BRITIS H S TAND ARD AE RO S PAC E S E RIE S

BS A 3 1 3 : 1 997
IS O 1 2 2 61 : 1 996

Aerospace —
Screws, pan head,
internal offset
cruciform rib b ed or
unrib b ed drive, p itch
diameter shank, long
length MJ threads,
metallic material,
coated or uncoated,
strength classes less
than or equal to
1 1 0 0 MPa —
D imensions

IC S 49 . 0 3 0 . 2 0


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BS A 313:1997

Committees responsible for this
British Standard
The p rep aration of this Britis h S tandard was entrus ted to Technical

C ommittee AC E /1 2 , Aerosp ace fas teners and fas tening s ystems , up on which
the following b odies were rep res ented:

British Indus trial Fasteners Federation
Minis try of D efence
S ociety of Britis h Aerosp ace C omp anies

This Britis h S tandard, having
b een p rep ared under the
direction of the E ngineering
S ector Board, was p ub lis hed
under the authority of the
S tandards Board and comes

Amendments issued since publication

into effect on
1 5 March 1 9 97

Amd. No.
© BS I 0 1 - 1 9 9 9

The following BS I references
relate to the work on this
s tandard:
C om mittee reference AC E /1 2
D raft for comment 9 4/70 5 7 03 D C

ISBN 0 580 26648 6

D ate

C omments


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BS A 313:1997

Contents
Page
Committees responsib le
National foreword

ii

1

Scope

1

2

Normative references

1

3

C onfiguration and dimensions

1

Figure 1

1

Table 1

2

List of references

© BSI 01 - 1 999

Inside front cover

Inside back cover

i


Li cen sed Copy: Lon d on Sou th Ban k U n i versi ty, Lon d on Sou th Ban k U n i versi ty, Sat Dec 09 03: 32: 42 G M T+00: 00 2006, U n con trol l ed Copy, (c) BSI

BS A 31 3:1 997

National foreword

This British Standard has been prepared by Technical Committee ACE/1 2. It is

identical with ISO 1 2261 : 1 996,

Aero sp ace — Screw s ,

p an head,

internal o ffset

cruciform rib b ed o r unrib b ed driv e, p itch diam eter s hank, long length MJ thread,
m etallic m aterials,

coated o r uncoated,

to 1 1 00 MPa — Dim ensio ns,

strength clas ses less than or eq ual

published by the International Organization for

Standardization (ISO).

Cross-references
Publication referred to

ISO 3353: 1 992

C orresponding British Standard

BS 2A 231 : 1 993

Rolled threads for b olts.

Lead and

runout req uirem ents

(Identical)
ISO 5855- 2: 1 988

BS 6293

Aero sp ace.

Part 2: 1 994

MJ threads

Lim it dim ensions for b olts and nuts

(Identical)
ISO 791 3: 1 994

BS 2A 296: 1 995

Bolts and screw s,

m etric.

Tolerances of

fo rm and p os ition

(Identical)
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 and 2, 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

© BSI 01 - 1 999


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BS A 313:1997

1 Scope

ISO 3353: 1 992 ,

Aero sp ace — Rolled threads fo r

b olts — Lead and runout req uirem ents .

This International Standard specifies the
dimensions of pan head screws with internal offset
cruciform ribb ed or unribb ed drive, pitch diameter

ISO 5855- 2 : 1 988,

Aeros p ace — MJ threads —

Part 2: Lim it dim ensions for b olts and nuts .

shank and long length MJ threads, in metallic

ISO 791 3: 1 994,

material, coated or uncoated, with strength classes

m etric — Tolerances o f fo rm and p os ition .

1)

less than or equal to 1 1 00 MPa.

ISO 1 42 75: —

This International Standard is applicab le to the

cruciform ,

Aerosp ace — Drives , internal, offset

rib b ed — Metric series .

1)

compilation of aerospace product standards.

,

Aeros p ace — Bolts and screw s,

ISO 1 42 76: —

,

Aerosp ace — Drives , internal, offset

crucifo rm — Metric series .

2 Normative references
The following standards contain provisions which,

3 Configuration and dimensions

through reference in this text, constitute provisions

See Figure 1 and Tab le 1 . D imensions and

of this International Standard. At the time of

tolerances are expressed in millimetres. They are

publication, the editions indicated were valid. All

applicable after any surface coating, but before the

standards are subj ect to revision, and parties to

application of any lubricant.

agreements based on this International Standard
are encouraged to investigate the possibility of
applying the most recent editions of the standards

Tolerances of form and position are specified in
ISO 791 3.

indicated b elow. Memb ers of IEC and ISO maintain
registers of currently valid International Standards.

Figure 1

1)

To b e published.

© BSI 01 - 1 999

1


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BS A 3 1 3 : 1 997

Tab le 1

D

D iame te r
Thre ad

co de

1

2

D

D

3

K

4

L

b cd
1

L

b cd
2

L

3

L

R

d
4

T

0

± 0 ,1 3

040

D

a

MJ4× 0, 7 – 4h6h

min.

3, 54

6, 7

– 0, 3

8

no m.

to l.

3

0

no m.

tol .

2, 4

min.

0, 4

± 0 ,3

max .

2

nom.

14

1 6 to 5 6

0, 4

16

2 0 to 7 0

0, 5

tol.

max. min.

D rive
co de

1,6

0, 4

R4

2

0, 5

R5

2,4

0, 6

2,8

0, 7

3, 2

0, 8

4

1

R1 0

4, 8

1,2

R1 2

e

0

– 0, 5

– 0, 2

05 0

MJ5 × 0, 8 – 4h6h

4, 48

8, 7

10

3, 4

3

060

MJ6× 1 – 4h6 h

5, 35

1 0, 7

12

4, 2

3, 6

070

MJ7× 1 – 4h6 h

6, 3 5

1 2, 7

14

5, 2

± 0 , 5 4, 2

080

MJ8× 1 – 4h6 h

7, 35

1 4, 7

16

6, 2

4, 8

100

MJ1 0× 1 , 2 5 – 4h6 h

9, 1 9

1 8, 7

20

7, 9

6

120

MJ1 2 × 1 , 2 5 –4h6 h

22, 7

24

9, 8

7, 2

0, 5

0

18

2 2 to 84

20

2 4 to 9 8

22

2 6 to 1 1 2

26

3 2 to 1 40

0, 8

30

3 6 to 1 6 8

0, 9

– 0 ,2

4
0, 7

0, 7

R6

R8

0

11,19

– 0, 3

0, 8

0, 9

6

0
–

a
b
c
d

I n accordance with I S O 5 85 5 - 2
Firs t length corres p onding to firs t
C onditions

4 for

2

1

min. and

L

2

L

4

length

max. cannot b e ob tained s imultaneous ly.

Increments :

2 for

e

L

0 ,3

L <
L
4

4

1 00

> 1 00

In accordance with IS O 1 42 7 5 or IS O 1 42 7 6

© BS I 0 1 - 1 99 9


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List of references

See national foreword.

© BSI 01 - 1 999

BS A 313:1997


Li cen sed Copy: Lon d on Sou th Ban k U n i versi ty, Lon d on Sou th Ban k U n i versi ty, Sat Dec 09 03: 32: 42 G M T+00: 00 2006, U n con trol l ed Copy, (c) BSI

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