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 standard:
Committee reference FME/9
Draft for comment 10/30205437 DC

Publication history

First published March 1973
Second (present) edition, December 2010

Foreword

Publishing information

This British Standard is published by BSI and came into effect on 31 December 2010. It was prepared by Technical Committee FME/9, Fasteners. A list of organizations represented on this committee can be obtained on request to its secretary.

Supersession

This British Standard supersedes BS 4933:1973, which is withdrawn.

Information about this document

This is a full revision of the standard and introduces the following principal changes.

The range of products specified to this standard has been extended since the first edition was published in 1973; in particular the mechanical property classes to BS EN ISO 898‑1 that now include 8.8 and 10.9.

No ISO product standards have been produced for fasteners to this standard.

A major use of some types of fasteners in this standard is in the steel construction industry, where their use might be subject to the requirements of the Construction Products Directive [1]. BS EN 15048 has been written to provide the harmonization requirements for non preloaded structural fasteners and CE marking.

To meet the loadability requirements of BS EN 15048, nuts conforming to BS EN ISO 4032, BS EN ISO 4033 and BS EN ISO 4034 should be used. Requirements are also included for maintaining the loadability requirements when thick protective coatings are applied that need modified thread tolerances for assembly of the bolt and nut combination.

The additional thread diameters M30 and M36, which are commonly used in the steel construction industry, have been included for cup and countersunk bolts and screws in the main dimensional tables.

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.

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 British Standard specifies requirements and provides general dimensions and tolerances for the following types of cup head and countersunk head bolts and screws:

cup head bolts and screws;
cup head bolts with nibs;
cup head square neck bolts;
90° countersunk head bolts and screws;
90° countersunk head bolts with nibs;
90° countersunk head square neck bolts;
120° countersunk head square neck bolts.

Mechanical properties for steel bolts and screws are specified in BS EN ISO 898‑1.

This British Standard also specifies requirements for the nuts to be provided with bolts and screws conforming to this standard.

NOTE 1 A table summarizing the key requirements of BS 4933 is included in Annex A. This table does not list every requirement in BS 4933 but is just intended as a quick reference for users.

NOTE 2 It is considered that the range of nominal sizes included in this standard is 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 is provided in Annex B.

2 Normative references

3 Manufacture and property classes of steel bolts and screws

3.1 General requirements

3.2 Method of production

3.3 Property classes

4 Mechanical properties of steel bolts and screws

5 General dimensions and tolerances

6 Length of bolts and screws

7 Ends of bolts and screws

8 Screw threads

8.1 General

8.2 Tolerances

8.3 Length of thread on bolts

8.4 Screws

9 Nuts

10 Finish

10.1 General

10.2 Coated finishes

11 Marking and identification of bolts and screws

12 Inspection and testing

13 Complete designation for the purpose of an enquiry or order

13.1 Information to be given

13.2 Special requirements or options

Bibliography

BS 4933:2010

Specification for ISO metric black cup and countersunk head bolts and screws with hexagon nuts

Current

Published:

31 Dec 2010