Bsi bs a 301 1989 (2000) iso 8168 1988

BRITISH STANDARD AEROSPAC E SERIES

BS A 301 :1 989
ISO 81 68:1 988

Specification for

Procurement of
corrosion and
heat-resisting steel
bolts with strength
classification 1 1 00 MPa
and MJ threads

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


BS A 301:1989

Committees responsible for this
British Standard
The preparation of this British Standard was entrusted by the Aerospace
Standards Policy Committee (ACE/- ) to Technical Committee ACE/1 2 upon
which the following bodies were represented:
Civil Aviation Authority (Airworthiness Division)
Electronic Engineering Association
Ministry of Defence
Society of British Aerospace Companies Limited

This British Standard, having
been prepared under the

direction of the Aerospace
Standards Policy Committee,
was published under the
authority of the Board of BSI
and comes into effect on

Amendments issued since publication

31 October 1 989

Amd. No.
© BSI 01 - 2000

The following BSI references
relate to the work on this
standard:
Committee reference ACE/1 2
Draft for comment 86/74336 DC

ISBN 0 580 17461 1

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

Date of issue

Comments


BS A 301:1989

Contents
Page
Committees responsible

Inside front cover

National foreword

ii

1

Scope and field of application

1

2

References

1

3

Definitions

1

4

Quality assurance

2

5

Requirements

3

Figure 1 — Head structure and grain flow

14

Figure 2 — Distortion in fillet area

15

Figure 3 — Grain flow in thread

15

Figure 4 — Non- permissible laps, seams and surface irregularities

16

Figure 5 — Permissible laps, seams and surface irregularities

16

Figure 6 — Metallurgical specimens

17

Table 1 — Technical requirements and test methods

4

Table 2 — Qualification testing requirements for bolt samples

8

Table 3 — Summary of qualification and acceptance tests

9

Table 4 — Surface discontinuities and contamination

9

Table 5 — Minimum tensile and double shear loads for qualification
and acceptance tests

10

Table 6 — Qualification and acceptance values for tension fatigue test

10

Table 7 — Thread discontinuities — Maximum depth of permissible faults

10

Table 8 — Classification of defects

11

Table 9 — Sampling plans for visual inspection and inspection of
dimensional characteristics

12

Table 1 0 — Sampling plans for the inspection of mechanical and
metallurgical characteristics

12

Table 1 1 — Variable sampling for tensile and shear
tests (alternative method)
Publications referred to

© BSI 01 - 2000
Reprodu ced by I H S u n d er l i cen se wi th BSI - U n con trol l ed Copy

13
Inside back cover

i

BS A 301 :1 989

National foreword

This British Standard, which has been prepared under the direction of the
Aerospace Standards Policy Committee, is identical with ISO 81 68: 1 988
“Aerospace — Corrosion- and heat-resisting steel bolts with strength
classification 1 1 00 MPa and MJ threads — Procurement specification ” published
by the International Organization for Standardization (ISO).
Cross-references
International Standard

C orresponding British Standard

ISO 2859- 1 : 1 974

BS 6001 Sampling procedures for inspection by
attributes
Part 1 : 1 972 Specification for sampling plans indexed by
acceptable quality level (AQL) for lot-by-lot inspection
(Technically equivalent)

ISO 3534: 1 977

Statistical terminology
Glossary of terms relating to probability
and general terms relating to statistics

BS 5532

Part 1 : 1 978
(Identical)
ISO 5855- 2: 1 981

BS 6293

MJ threads for aerospace construction
Specification for dimensions for bolts

Part 2: 1 982

and nuts

(Identical)
The Technical Committee has reviewed the provisions of ISO 3452, ISO 3453 and
ASTM E 1 1 2- 84 to which reference is made in the text, and has decided that they
are acceptable for use in conj unction with this standard. It is envisaged that a
British Standard corresponding to ISO 7961 will be published.
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 1 8, 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 01 - 2000


BS A 3 0 1 : 1 989

1 S cop e and fie ld of ap p lication

This International Standard specifies the characteristics and quality assurance requirements for bolts with
normal heads, made of corrosion- and heat- resisting steel, having a tensile strength classification
of 1 1 00 MPa and MJ threads, and intended for use in aerospace construction.
This International Standard applies to bolts as defined above, provided that reference is made to this
International Standard in the product standard or definition document.
2 Re fe re nce s

Sampling procedures for inspection by attributes — Part 1: Sampling plans indexed by
acceptable quality level (AQL) for lot-by-lot inspection1 ) .

ISO 2859- 1 ,

ISO 3452,

Non-destructive testing — Penetrant inspection — General principles.

ISO 3453,

Non-destructive testing — Liquid penetrant inspection — Means of verification.

ISO 3534,

Statistics — Vocabulary and symbols.

ISO 5855- 2,
ISO 7961 ,

Aerospace construction — MJ threads — Part 2: Dimensions for bolts and nuts.

Aerospace — Bolts — Test methods 2) .

ASTM E 1 1 2- 84,

Standard methods for determining average grain size.

3 D e finitions
3.1
p ro ducti on b atch

quantity of finished bolts manufactured, using the same process, from a single material cast (single heat
of alloy) , having the same basic part number and diameter, heat- treated together to the same specified
condition and produced as one continuous run
3.2
insp e ction lot

quantity of bolts from a single production batch with the same part number which completely defines the
bolt
3 . 3 D iscontinuitie s
3.3.1

crack

rupture in the material which may extend in any direction and which may be intercrystalline or
transcrystalline in character
3.3.2
se am

open surface defect resulting from extension of the material
3.3.3
lap

surface defect caused by folding over metal fins or sharp corners and then rolling or forging them into the
surface
3.3.4
inclusions

non- metallic particles originating from the material manufacturing process. These particles may be
isolated or arranged in strings

1)
2)

At present at the stage of draft. (Revision, in part, of ISO 2859: 1 974. )
At present at the stage of draft.

© BSI 01 - 2000
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

BS A 301 :1 989

3.4
simple random sampling

the taking of items from a population of items in such a way that all possible combinations of items
have the same probability of being chosen3)
n

N

n

3.5
critical defect

a defect that, according to judgement and experience, is likely to result in hazardous or unsafe conditions
for individuals using, maintaining or depending3)upon the considered product, or that is likely to prevent
performance of the function of a major end item
3.6
maj or defect

a defect, other than critical, that is likely to3)result in a failure or to reduce materially the usability of the
considered product for its intended purpose
3.7
minor defect

a defect that is not likely to reduce materially the usability of the considered product for its intended
purpose, or that is a departure from established specification having little bearing on the effective use or

operation of this product3)
3.8
sampling plan

a plan according3)to which one or more samples are taken in order to obtain information and possibly to
reach a decision
3.9
limiting quality (LQ)

in a sampling plan, a quality level which corresponds to a specified and relatively low probability of
acceptance: for the purposes of this International Standard, a 10 % probability of acceptance (LQ10). It is
the limiting lot quality characteristic that the consumer is willing to accept with a low probability that a
lot of this quality would occur3)
3.1 0
acceptable quality level (AQL)

a quality level which in a sampling plan corresponds to a specified but relatively high probability of
acceptance
it is the maximum percent defective (or the maximum number of defects per hundred units) that, for
purposes of sampling inspection, can be considered satisfactory as a process average3)
4 Quality assurance
4.1 General
4.1 .1

Approval of manufacturers

4.1 .2

Qualification of bolts

The manufacturer shall conform to the quality assurance and approval procedures in effect in the
purchaser’s country: the purpose of these procedures is to ensure that a manufacturer has a quality system
and the capability for continuous production of bolts complying with the specified quality requirements.
The granting of an approval of the manufacturer is a function of the Certification Authorities, or their
appointed representative, who may be the prime contractor.
The purpose of qualification inspections and tests of bolts is to check that the design and manufacturing
conditions of a bolt allow it to satisfy the requirements of this International Standard.
The granting of qualification of a bolt is a function of the Certification Authorities in the purchaser’s
country, or their appointed representative, who may be the prime contractor.

3) Definition taken from ISO 3534:1977. (ISO 3534 is currently being revised by ISO/TC 69,

2

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

Ap p lication o f s tatis tical m eth ods.

)

© BSI 01-2000


BS A 3 0 1 : 1 989

4.1 .3

Acceptance of bolts

The purpose of acceptance inspections and tests of bolts is to check, as simply as possible, using a method

which is inexpensive and representative of actual conditions of use, with the uncertainty inherent in
statistical sampling, that the bolts satisfy the requirements of this International Standard.
Acceptance inspections and tests shall be carried out by the manufacturer, or under his responsibility. The
manufacturer is responsible for the quality of the bolts manufactured.
4 . 2 Qualification insp e ction and te st conditions

Qualification inspections and tests (requirements, methods, numbers of bolts) are specified in Table 1 .
They shall be carried out on
— each type and diameter of bolt,
— 25 bolts selected from a single inspection lot by simple random sampling.
The test programme may possibly be reduced, or the qualification of a bolt be granted, without inspection
or testing: any such decision shall be based on the results obtained on similar types and diameters of bolts
provided that the design and manufacturing conditions are identical.
The inspections and tests shall be repeated on any bolt if the manufacturing conditions have changed.
Table 2 indicates the allocation of bolt specimens for the inspections and tests.
Qualification inspections and tests are summarized in Table 3.
4 . 3 Acce p tance insp e ction and te st conditions

Acceptance inspections and tests (requirements, methods, numbers of bolts) are specified in Table 1 ; they
shall be carried out on each production batch or inspection lot. Bolts from the batch or lot to be tested shall
be selected by simple random sampling.
Each bolt may be submitted to several inspections or tests.
The bolts to be subj ected to destructive inspections or tests may be those on which non- destructive
inspections or tests have been carried out.
If a more stringent inspection is deemed necessary, all or part of the qualification inspections and tests may
be performed during the acceptance inspection and testing. In this case, the number of bolts submitted to
these inspections and tests is the same as that submitted for qualification inspections and tests.
Production batches or inspection lots declared unacceptable after the acceptance inspections and tests shall
be submitted for re- inspection or re- testing only after all defective units have been removed and/or defects
have been corrected.

Twice the normal sample size shall be used for re- inspecting or re- testing the attributes causing initial
rej ection; the same acceptance level shall be used.
Acceptance inspections and tests are summarized in Table 3.
5 Require me nts

The requirements of this International Standard are given in Table 1 and, unless otherwise specified, they
apply to bolts ready for use. Unless otherwise specified, the test temperature shall be the ambient
temperature. These requirements complement the requirements of all other standards or specifications
referenced in the product standard or in the definition document of the bolt.

© BSI 01 - 2000
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 A 3 0 1 : 1 989

Tab le 1 — Te chnical re quire me nts and te st me thod s
Insp e ctio n and te st

C lau se
No .

5.1

5.2

C haracte risti c

Mate rials

D ime nsio ns

Te chni cal re qui re me nt

me tho d

In accordance with the product

As stated in the

standard or definition document.

material specification.

In accordance with the

Standard gauging.

requirements of the product
standard or definition document.
5.3
5.3.1

Q/A

a

S amp le siz e

Q

22

A

Table 8
and Table 9

Manufacturing

Forging

The heads of the bolts shall be

The equipment used

formed by a hot or cold forging

shall be approved.

process before heat treatment.
In the case of hot forging, the
equipment shall be such that a
constant temperature of less
than 1 090 ° C is guaranteed

5.3.2

Heat treatment

throughout the production batch.
The forged blanks shall be heat
treated to produce the properties
required by the product standard or
definition document.
No blank shall be heat treated more
than twice. The heat treatment
media or atmosphere shall not cause
any surface contamination except as

5.3.3

Machining

permitted by

5.5.3

The amount of material removed

See

5.5.1.

See

5.5.1.

from the bearing surface of the head
and the shank of the heat- treated
blanks shall be as little as
practicable consistent with the
removal of surface contamination,
production of a smooth surface and
maintenance of optimum grain flow
around the under- head fillet radius

5.3.4

Cold rolling

as shown in Figure 1 .
The fillet radius shall be cold rolled
after heat treatment and machining
so as to remove all visual signs of
machining and to create superficial
cold working; this may cause
distortion which shall not exceed
the values shown in Figure 2; this
requirement is not applicable to
fully threaded screws or bolts with

5.3.5

5.3.6

a

Threads
Surface
roughness

a nominal diameter less than MJ5.
To be formed by a single rolling
process after all heat treatment.
In accordance with the product

Visual comparison

standard or definition document.

method or thumbnail
comparison method.

Q = qualification inspection and test conditions (see
A = production acceptance test conditions (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

Q

3

A

Table 8
and Table 9

4.2)

4.3)

© BSI 01 - 2000


BS A 3 0 1 : 1 989

Tab le 1 — Te chnical re quire me nts and te st me thod s

C lause
No .

5.3.7

C haracte ri stic

Surface
coating

Insp e cti o n and te st

Te chnical re qu i re me nt

me tho d

In accordance with the product standard

See applicable

or definition document.

coating
specification.

5.4

Q/A

S amp le si z e

Q

3

A

Table 8
and Table 9

Me chanical
p rop e rtie s

5.4.1

Tensile
strength

In accordance with the minimum tensile

See ISO 7961 .

loads specified in Table 5.

Q

5

A

Table 1 0,

Tensile tests are not applicable to the

column B,

following:

or Table 1 1

a) protruding head bolts of grip length
less than 2

D

;

b) countersunk head bolts of grip length

less than 2 , 5

D

;

c) threaded- to- head b olts of overall
length less than 3

D

or bolts having an

overall length less than 1 8 mm.
In such cases, acceptance shall be based
on the results from tests bars of the same
material, heat- treated with the same

5.4.2

Double shear
strength

process cycle.
In accordance with the values specified

See ISO 7961 .

in Table 5.

Q

5

A

Table 1 0,

The grip length shall not be shorter than

column B

twice the nominal shank diameter for

or Table 1 1

protruding head b olts or shorter than 2 , 5
times the nominal shank diameter for

5.4.3

Tension
fatigue
strength

countersunk heads.
Life:

See ISO 7961 .

— mean value

65 000 cycles min.

— individual value

45 000 cycles min.

Q

10

A

Table 1 0,
column B

1 30 000 cycles max.
Frequency:
Loads:

1 40 Hz
see Tab le 6

Unb roken bolts shall b e rendered
unusable.
Unless otherwise specified, fatigue tests
shall not b e carried out on the following:
a) bolts with drilled shanks;
b) b olts of thread size smaller

than 5 mm;
c) bolts having a grip length of less than
twice the diameter.
5.5

Me tallurgical
p rop e rtie s

© BSI 01 - 2 000
Reprodu ced by I H S u n d er l i cen se wi th BSI - U n con trol l ed Copy

5


BS A 3 0 1 : 1 989

Tab le 1 — Te chnical re quire me nts and te st me thod s
C lause
No .

5.5.1

C haracte risti c

Te chni cal re qui re me nt

Insp e cti o n and te st me tho d

Head-to-shank

Flow lines in the fillet area

Specimens shall be taken

grain flow and

immediately below the

from the finished bolt

fillet work

surface shall closely conform

(see Figure 6) . The sections

effect

to the fillet contour

to be examined shall be

(see Figure 1 ) .

subj ected to an appropriate

See Figure 1 for breaks in flow

macroscopic etchant.

lines.

Macroscopic examination

If there is doubt about the

of a longitudinal section at

acceptability of the grain flow

a suitable magnification

or fillet work effect, the

(X1 0 to X20) .

Q/A

S amp le siz e

Q

A

A

Table 1 0,
column B

acceptability shall be decided

by the results of the
acceptance fatigue test.
5.5.2

Thread grain

The grain flow shall be

flow and work

continuous and shall follow

effect

the general thread contour

Macroscopic examination.

Q

4

A

Table 1 0,
column B

with the maximum density at
the bottom of the root radius
(see Figure 3) .

5.5.3

5.5.4

Microstructure

Grain size

The microstructure shall be

The sections to be

free from overheating and

examined shall be

alloy segregation which is

subj ected to an appropriate

likely to affect the mechanical

microscopic etchant.

or physical properties of the

Microscopic examination at

bolt.

a magnification of X1 00.

The grain size of the finished

Microscopic examination

bolts when compared with

at a magnification of X1 00.

plate II in ASTM E 1 1 2- 84

Q

4

A

Table 1 0,
column B

Q

4

A

Table 1 0,
column B

shall not be coarser than 5.
Isolated grains not exceeding
a mean diameter a of 0, 23 mm
are acceptable.
5.5.5

Surface

See Table 4.

contamination

Microscopic examination
at a magnification of X1 00.

Q

4

A

Table 1 0,
column B

5.5.6

Discontinuities

The bolts shall not show any

Penetrant flaw detection in

discontinuity equal to or

accordance with ISO 3452

greater than the limitations

and ISO 3453.

specified in this International

In cases of doubt,

Standard (see Table 4). Care

microscopic examination at

shall be exercised to avoid
confusing cracks with other

a magnification of X1 00
shall be carried out.

discontinuities.
Cracked bolts and those

Q

25

A

Penetrant:
Table 8
and Table 9
Microscopic
examination:
Table 1 0,
column B

having discontinuities
transverse to the axis (i. e. at
an angle of more than 1 0 ° to
the longitudinal axis) shall be
rej ected and destroyed.
a

Mean diameter = average of the maj or and minor axes of an individual grain.

6
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 01 - 2000


BS A 3 0 1 : 1 989

Tab le 1 — Te chnical re quire me nts and te st me thod s

C lau se
No .

5 .5 .6.1

5 .5 .6.2

5.6

C haracte ri sti c

Te chni cal re qu i re me nt

Insp e cti o n and te st me tho d

Q/A

S amp le si z e

Head and shank See Table 4 for the limits of
Thread

Prod uct
ide ntification

acceptance.
Acceptance limits
(see Figure 4 and Figure 5):
— in the unloaded part of
the fillet, above the pitch

diameter, see Table 7;
— at the crest of the
threads, see Table 7 —
values to be increased by
half the difference between
the actual measured
diameter and the minimum
external thread diameter
(see ISO 5855-2);
— a slight irregularity in
the form of the crests in
relation to the basic profile
is acceptable (see Figure 5).
Marking in accordance with Visual inspection.
the product standard or
definition document.
Bolts to be “package-marked”
shall be packed and identified
in accordance with
and

Q
A

25
Table 8
and Table 9

A

100 %

A

100 %

5 . 7. 1

5 . 7. 2

5.7
5 .7.1

5 .7.2

D e live ry

Packaging

Labelling

© BSI 01-2000
Reprodu ced by I H S u n d er l i cen se wi th BSI - U n con trol l ed Copy

The bolts shall be packed in Visual inspection.
such a way as to prevent any
damage or corrosion occurring
in the course of handling,
transportation and storage.
Each basic package shall only

contain bolts with the same
part number and the same
inspection lot number.
Visual inspection.
Each basic package shall
carry a label on which the
complete part number,
quantity, production batch
number and inspector’s stamp
have been legibly recorded.

7


BS A 301 :1 989

Table 2 — Qualification testing requirements for bolt samples
Bolt sample number
Type of test

Defined in

1

2

3

4

5

6

7

8

9

10

11

12

Uncoated

13

14

15

16

17

18

19

20

21

22

23

24

25

C oated

Non-destructive
D imensions
Surface
roughness

× × × × × × × × × × × × × × × × × × × × × ×

5.2
5.3.6

× × ×
× × ×

Surface coating

5.3.7

D iscontinuities

5.5.6

× × × × × × × × × × × × × × × × × × × × × × × × ×

5.6

× × × × × × × × × × × × × × × × × × × × × × × × ×

Product
identification

Destructive
Tensile strength
D oub le shear
strength
Tension fatigue
strength

× × × × ×

5.4.1
5.4.2

× × ×

× ×
× × × × × × × × × ×

5.4.3

Head- to- shank

5.5.1

× × × ×

5.5.2

× × × ×

Microstructure

5.5.3

× × × ×

Grain size

5.5.4

× × × ×

5.5.5

× × × ×

grain flow and
fillet work effect
Thread grain
flow and work
effect

Surface
contamination

8
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 01 - 2 000


BS A 301 :1 989

Table 3 — Summary of qualification and acceptance tests
Sample size for
Type of test

Defined in

Dimensions
Surface roughness
Surface coating
Tensile strength

5 .2

5 .3.6
5 .3.7
5 .4.1

Double shear strength
Tension fatigue strength
Head-to-shank grain flow and fillet work effect
Thread grain flow and work effect
Microstructure
Grain size
Surface contamination
Discontinuities

5 .4.2
5 .4.3
5 .5 .1
5 .5 .2
5 .5 .3
5 .5 .4
5 .5 .5

5 .5 .6

Product identification
Packaging
Labelling

5 .6
5 .7.1
5 .7.2

qualification

22
3
3
5
5
10
4
4
4
4
4
25
25
—
—

tests

acceptance tests

Table 8 and Table 9
Table 8 and Table 9
Table 8 and Table 9
Table 10, column B
or Table 11
Table 10, column B
or Table 11

Table 10, column B
Table 10, column B
Table 10, column B
Table 10, column B
Table 10, column B
Table 10, column B
Penetrant: Table 8
and Table 9
Microscopic
examination: Table 10,
column B
Table 8 and Table 9
100 %
100 %

Table 4 — Surface discontinuities and contamination

Dimensions in millimetres
Maximum depth normal to
surface for bolts having a
Location

Permissible discontinuity

nominal diameter
up to 1 6 mm

Heat-to-shank fillet and root
of thread

Shank diameter and bearing
surface of head

Non-bearing surface of head
Any other location

© BSI 01-2000
Reprodu ced by I H S u n d er l i cen se wi th BSI - U n con trol l ed Copy

No discontinuities
No surface contamination
Seams not extending into head to shank 0,12
fillet or root of thread
No surface contamination
Laps, seams and inclusions
0,25
Surface contamination
0,025
Surface contamination
0,025

1 8 mm and above

0,15
0,3
0,025
0,025

9

BS A 3 0 1 :1 989

Tab le 5 — Minimum te nsile and doub le shear loads for qualification and acce ptance te sts
Thre ad

Te nsile stre ngth te st

Load,
D iame ter

Protruding head
kN

Pitch

mm

mm

0,5
0,7
0,8
1
1
1
1,25
1,25
1,5
1,5

1,5
1,5
1,5
2

3
4
5
6
7
8
10
12
14
16
18
20
22
24

5,98
10,47
16,83
23,93
34,02
45,85
71,65
107
145
193

249
311
380
442

min.
Countersunk head
kN

4,78
8,38
13,46
19,14
27,22
36,68
57,32
85,6
116
154
199
249
304
354

D oub le she ar stre ngth te st

Lo ad

C ross-se ctional

min.
kN

are a

mm 2

5,439
9,517
15,296
21,753
30,93
41,682
65,136
97,128
131,562
175,613
225,949
282,571
345,478
401,68

9,33
16,59
25,92
37,32
50,8
66,4
104,3
149

203
266
337
415
502
597

C ross-se ctional
are a

mm2

7,069
12,566
19,635
28,274
38,484
50,265
78,54
113,1
153,9
201,1
254,5
314,2
380,1
452,4

Tab le 6 — Qualification and acce ptance value s for te nsion fatigue te st
Thre ad

Protruding he ad

H igh load
D iame te r

mm

5
6
7
8
10
12
14
16
18
20
22
24

±2%
kN

Pitch

0,8
1
1
1
1,25

1,25
1,5
1,5
1,5
1,5
1,5
2

mm

7,74
11,01
15,65
21,09
32,96
49,22
66,7
88,78
114,5
143
174,8
203,3

Lo w lo ad

±2%
kN

0,77
1,1

1,56
2,11
3,3
4,92
6,67
8,88
11,45
14,3
17,48
20,33

C ounte rsunk he ad

H igh lo ad

±2%
kN

6,19
8,8
12,52
16,87
26,37
39,38
53,36
70,84
91,54
114,5
139,8
162,8

Lo w load

±2%
kN

0,62
0,88
1,25
1,69
2,64
3,94
5,34
7,08
9,15
11,45
13,98
16,28

Tab le 7 — Thread discontinuitie s —
Maximum de pth of pe rmissib le
faults

(see

Thre ad p itch

0,5
0,7
0,8

1
1,25
1,5
2

10

5.5.5.2

)

Dimensions in millimetres

0,06
0,08
0,09
0,12
0,15
0,18
0,24

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

D e p th

© BSI 01-2000


BS A 301 :1 989

Table 8 — Classification of defects
Acceptable
Category of

quality

defect

level
(AQL)

Major “A”

0,065 %

Major “B”

1%

Minor “A”

2,5 %

Minor “B”

4%

© BSI 01-2000
Reprodu ced by I H S u n d er l i cen se wi th BSI - U n con trol l ed Copy

Characteristics

Magnetic flaw detection
Thread size
Shank diameter
Grip length
Fillet radius: distortion and dimensions
Drilled holes missing when required
Surface roughness
Burrs and tool marks
Surface coating
Identification
Depth of lightening hole in head
Thread form
Incomplete threads
Squareness between head-bearing surface and shank
Straightness of shank
Overall length
Head diameter
Head angle (countersunk head)
Lightening hole diameter
Drilled hole location and diameter
Wrenching configuration
Concentricity of head and shank
Coaxiality of shank and thread pitch diameter
Chamfer on thread end
Hexagon head: chamfer and washer face
Collar height
Head height

11


BS A 301:1989

Table 9 — Sampling plans for visual inspection and inspection of dimensional characteristics
Production batch size

91 to
91 to
151 to
281 to
501 to
1 201 to
3 201 to
10 001 to
35 001 to
150 001 to

Acceptance number (Ac) and limiting quality (LQ10)
in accordance with the acceptable quality level (AQL)
AQL 0,065 %
AQL 1 %
AQL 2,5 %
AQL 4 %
LQ10
LQ10
LQ10
LQ10
Ac

Ac
Ac
Ac
%
%
%
%

Sample size

150
150
280
500
1 200
3 200
10 000
35 000
150 000
500 000

13
20
32
50
80
125
200
315
500

800

—

—

0

16

G

G

G

G

G

G

G

G

G

G

E

E

G

0
G

1

G

E

1
2
3
5
7
10
—

1,2
G

0,49

E

7,6
6,5
5,4
4,6
3,7
3,1
—

—
1
2
3
5
7
10
14
21
—

—
18
16
13
11
9,4
7,7
6,4
5,6
—

—
2
3
5
7
10
14
21

—
25
20
18
14
12
10
9

—

—

E

E

Use the sampling plan above (sample size and Ac).
Use the sampling plan below (sampling size and Ac).
NOTE The data given in Table 9 are based on single sampling plans for a standard inspection, as specified
in ISO 2859-1 (Table 2-A and Table 6-A).

A 100 % inspection should be performed when the sample size is as large as or larger than the batch size.
Other sampling plans specified in ISO 2859-1 may be used (double or multiple sampling), but these shall be chosen in such as way
as to ensure an equivalent quality level.
As regards those manufacturers who carry out an inspection during the manufacturing process (inspection on a machine and/or
inspection between operations), the sampling plan for the final inspection shall be compiled in such a way that the overall inspection
plan shall guarantee an equivalent quality level.
E

G

Table 10 — Sampling plans for the inspection of
mechanical and metallurgical characteristics

Production batch size

Up to 500
501 to 3 200
3 201 to 35 000
Above 35 000

12

Sample size
Non-destructive Destructive
tests
tests
A
B

8

13
20
32

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
5
5
8

Acceptance
number

0
0
0
0

© BSI 01-2000


BS A 301:1989

Table 11 — Variable sampling for tensile and shear tests (alternative method)
Production
batch size

Sample
number

Acceptable quality level approximately AQL 1 %
First sample
Combined
sample
Sample size
Total

K

K

a

Under 1 51

1 51 to

300

301 to

500

First

4

4

Second

8

12

First
Second
First
Second
First

501 to 1 300

Second
First

1 301 to 3 200
Above 3 200

5

5

10

15

6

6

12

18

7

7

14

21

K

r

t

2, 42

1 , 35

—

—

—

1 , 72

2, 21

0, 89

—

—

—

1 , 74

2, 22

0, 94

—

—

—

1,7

2, 32

1,1

—

—

—

1 , 78

8

8

2, 48

0, 99

—

Second

16

24

—

—

1 , 81

First

10

10

2, 34

1 , 31

—

Second

20

30

—

—

1,8

Evaluate each sample by tensile or shear tests as follows:
First sample: Accept if

X KS WM
1

–

a

1

Rej ect if

X KS
1

–

r

<

1

M

Take second sample if batch is doubtful; evaluate as follows:

X KS WM

Second sample: Accept if

t

–

t

t

Rej ect if

X KS M
t

–

t

t

<

Definition of terms:

X
K K
1

is the average of

a,

r

and

K

t

X

1

individual values in the first sample;

are coefficients of

S

which is the best estimate of standard deviation and which are used

to determine acceptance or rej ection of the batch represented by the sample;

where

N
CX
1

is the number of parts in the first sample,

2
1

M
X

(

is the sum of squares of

C X1)2

X

1

values,

is the square of the sum of

X

1

values;

is the minimum tensile or minimum shear value according to Table 5;
is the average of

t

X

t

individual values in the combined samples;

where

N
CX
t

is the number of parts in the combined sample,

2
t

(

C Xt)2

is the sum of squares of

X

t

values,

is the square of the sum of

© BSI 01 - 2000
Reprodu ced by I H S u n d er l i cen se wi th BSI - U n con trol l ed Copy

X

t

values.

13


BS A 3 0 1 : 1 989

NOTE

Cut grain acceptable in the zone defined by

specified in the product standard) ] .

Z dimensions [Z max. = R max. (where R max. is the minimum fillet radius

Figure 1 — H e ad structure and grain flow

14
Reprodu ced by I H S u n d er l i cen se wi th BSI - U n con trol l ed Copy

(see

5.5.1 )

© BSI 01 - 2000


BS A 3 0 1 : 1 989

Dimensions in millimetres

A

B o lt
no minal
d i ame te r

max.

B

C

max.

max.

5

1,5

6

1,5

7

1,5

8

2, 5

10

2, 5

12
14

0, 03

0, 025

3, 5
3, 5

16

3, 5

18

4, 5

20

4, 5

22

4, 5

24

4, 5

Figure 2 — D istortion in fille t are a

Figure 3 — Grain flow in thre ad

© BSI 01 - 2000
Reprodu ced by I H S u n d er l i cen se wi th BSI - U n con trol l ed Copy

(see

(see

5 . 3 . 4)

5.5.2)

15

BS A 3 0 1 :1 989

Figure 4 — Non-p ermissib le laps, se ams and surface irre gularities

Figure 5 — Pe rmissib le laps, seams and surface irre gularitie s

16
Reprodu ced by I H S u n d er l i cen se wi th BSI - U n con trol l ed Copy

(see

(see

5.5.5.2 )

5.5.5.2)

© BSI 01 - 2000