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 TDW/4
Draft for comment 09/30192598 DC

Publication history

First published March 1953
Second (present) edition, September 2009

Foreword

Publishing information

This British Standard is published by BSI and came into effect on 30 September 2009. It was prepared by Technical Committee TDW/4, Technical product realization. A list of organizations represented on this committee can be obtained on request to its secretary.

Supersession

This British Standard supersedes BS 1916‑1:1953, which is withdrawn.

Relationship with other publications

This British Standard is published in three parts:

Part 1 – Guide to limits and tolerances;
Part 2 – Guide to the selection of fits in BS 1916‑1;
Part 3 – Guide to tolerances, limits and fits for large diameters.

The ISO 286 (BS EN 20286) series establishes the ISO code-system for tolerances of linear sizes and is published in the following parts:

ISO 286‑1 (BS EN 20286‑1), ISO system of limits and fits – Part 1: Bases of tolerances, deviations and fits;

ISO 286‑2 (BS EN 20286‑2), ISO system of limits and fits – Part 2: Tables of standard tolerance grades and limit deviations for holes and shafts.

The ISO 286 series covers the metric system of limits and fits; the BS 1916 series provides guidance and recommendations on the equivalent inch system (imperial).

Information about this document

In view of the time elapsed since its original publication in 1953, this British Standard was reviewed in detail in 2009. It was decided that the technical provisions of the previous edition were still generally applicable, but the figures have been redrawn for ease of use, the wording of some guidance updated for clarity, and the opportunity was taken to update references to other standards.

Use of this document

As a guide, this part of BS 1916 takes the form of guidance and recommendations. It should not be quoted as if it were a specification or a code of practice and claims of compliance cannot be made to it.

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 part of BS 1916 gives guidance on tolerances, limits and fits for engineering sizes up to 19.69 in. The recommendations apply particularly to fits between cylindrical parts, designated as “holes” and “shafts”, in which case the term “size” refers to the diameter of the mating parts. The data may also be applied in appropriate cases, by suitable selection of the grades of allowance and tolerances, to fits between other than cylindrical mating parts, in which case the “size” refers to a length, width or other dimension instead of to a diameter.

The system described in this British Standard comprises suitable combinations of 16 grades of tolerance and 21 types of fit for both hole and shaft, ranging from fits of extreme interference to those of extreme clearance. All but very exceptional engineering requirements are covered, from very coarse work to fine gauge manufacture.

A selection of fits for general use is given in Figure 4, and further guidance on tolerances for shafts and holes for a wide range of fits is given in Part 2 of this British Standard, but it is intended that a particular industry or organization extracts and uses those limits which suit its own product. A unilateral hole basis system is recommended but a full range of holes suitable for use on a shaft basis system, unilateral or bilateral, is also included in the tables.

2 Normative references

3 Terms and definitions

4 Basis of conversion

5 Diameter steps

6 Explanation of the system

6.1 Fundamental tolerances

6.1 Fundamental deviations

7 Terminology

8 Selection of limits

9 Initial selection for normal use

10 Gauge limits

11 Equivalent fits

12 Limits for holes and shafts

Bibliography

BS 1916-1:2009

Limits and fits for engineering - Guide to limits and tolerances

Current, Under Review

Published:

30 Sep 2009