Publishing and copyright information

The BSI copyright notice displayed in this document indicates when the document was last issued.

The following BSI references relate to the work on this document:
Committee reference FME/9
Draft for comment 14/30283396 DC

Publication history

First published December 1963
Second edition, August 1967
Third edition, February 2001
Fourth (present) edition, October 2014

Foreword

Publishing information

This British Standard is published by BSI Standards Limited, under licence from The British Standards Institution, and came into effect on 31 October 2014. It was prepared by Technical Committee FME/9, Nuts and accessories. A list of organizations represented on this committee can be obtained on request to its secretary.

Supersession

This British Standards supersedes BS 3692:2001, which is withdrawn.

Relationship with other publications

This British Standard should be read in conjunction with BS EN ISO 898‑1 as it contains tables that reflect up-to-date best practice for mechanical properties of bolts.

Information about this document

The mechanical properties of the nuts in this British Standard do not conform to BS EN ISO 898‑2. Higher proof load values have been allocated to the revised property classes in BS EN ISO 898‑2 in order to ensure that fracture of the bolt generally occurs in the case of overloading.

CAUTION — Nuts in accordance with this standard cannot be fully loaded with sufficient assurance upto the yield point of the appropriate bolt, or beyond this, without the possibility of the nut thread being stripped, and for this reason it is essential that new designs of nuts for use with BS 3692 bolts and studs conforming to this standard conform to BS EN ISO 898‑2.

In order to differentiate nuts that conform to this British standard from that those that conform to BS EN ISO 898‑2 vertical bars have been added to the symbols for strength grade designations e.g. |8| instead of 8.

It has been assumed in the preparation of this British Standard that the execution of its provisions will be entrusted to appropriately qualified and experienced people, for whose use it has been produced.

Presentational conventions

The provisions of this standard are presented in roman (i.e. upright) type. Its requirements are expressed in sentences in which the principal auxiliary verb is “shall”.

Commentary, explanation and general informative material is presented in smaller italic type, and does not constitute a normative element.

Requirements in this standard are drafted in accordance with Rules for the structure and drafting of UK standards, subclause J.1.1, which states, “Requirements should be expressed using wording such as: ‘When tested as described in Annex A, the product shall ...’”. This means that only those products that are capable of passing the specified test will be deemed to conform to this standard.

Contractual and legal considerations

This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.

Compliance with a British Standard cannot confer immunity from legal obligations.

1 Scope

This standard gives the general dimensions and tolerances of precision hexagon bolts, screws and nuts with ISO metric threads in diameters from 1.6 mm to 68 mm inclusive.

This standard specifies mechanical properties of bolts, screws and nuts made of carbon steel and alloy steel when tested at an ambient temperature range of 10 °C to 35 °C.

NOTE 1 Fasteners (the term used when bolts, screws and nuts are considered all together) that conform to the requirements of this standard are evaluated at this ambient temperature range. They might not retain the specified mechanical and physical properties at elevated temperatures and/or lower temperatures.

This standard is not applicable to fasteners used in applications outside of the range −50 °C to +150 °C.

NOTE 2 Fasteners conforming to the requirements of this standard are used in applications ranging from −50 °C to +150 °C. The use of fasteners in applications outside of this range, and up to a maximum temperature of +300 °C, might need to be based on the advice of an experienced fastener metallurgist for determining appropriate choices for a given application.

NOTE 3 Nuts in accordance with this standard cannot be fully loaded with sufficient assurance up to the yield point of the appropriate bolt, or beyond this, without the possibility of the nut thread being stripped, and for this reason it is essential that new designs of nuts for use with BS 3692 bolts and studs conforming to this standard conform to BS EN ISO 898‑2.

NOTE 4 Nuts with an effective height of less than 0.6d and/or with a width across flats or outside diameter of less than 1.4d are excluded from the mechanical requirements specified.

The dimensional requirements of this British Standard are also applicable to non-ferrous and stainless steel bolts, screws and nuts.

Information on strength grade designation system for steel bolts and screws can be found in Annex A.

NOTE 5 The range of nominal sizes included in this British Standard is likely to be adequate for most of the applications for which this series is likely to be employed, but for the convenience of users requiring larger sizes, further information in relation to the derivation of tolerances is in Annex E.

NOTE 6 In addition to the definitive requirements, this standard also requires the items detailed in Clause 3 to be documented. For compliance with this standard, both the definitive requirements and the documented items have to be met.

2 Normative references

3 Information and requirements to be agreed and documented

3.1 Information to be supplied by the purchaser

3.2 Items to be agreed between the manufacturer and purchaser

4 General dimensions

5 Length of bolts and screws

5.1 Nominal length

5.2 Tolerance on length

6 Ends of bolts and screws

7 Screw threads

7.1 General

7.2 Tolerances

8 Length of thread on bolts and screws

8.1 Bolts

8.2 Tolerances

8.3 Screws

9 Dimensions of bolts and screws

10 Angularity and eccentricity of bolts, screws and nuts

11 Dimensions of nuts

12 Chamfering, washer facing and countersinking bolts, screws and nuts

12.1 Bolts and screws

12.2 Nuts

13 Material and manufacture of steel bolts and screws

13.1 Method of production

13.2 Chemical composition

13.3 Heat treatment

13.4 Decarburization

13.5 Rolling laps

14 Mechanical properties of steel bolts and screws

15 Strength grade designation system for steel nuts

16 Material and manufacture of steel nuts

16.1 Method of manufacture

16.2 Chemical composition

16.3 Heat treatment

17 Mechanical properties of steel nuts (excluding thin nuts)

18 Drilled bolts with split pin holes

19 Finishes

20 Marking and identification

20.1 Bolts and screws

20.2 Nuts

21 Inspection and testing

Bibliography

BS 3692:2014

ISO metric precision hexagon bolts, screws and nuts. Specification

Current

Published:

31 Oct 2014