National foreword

This British Standard has been prepared under the direction of the Machine, Engineers and Hand Tools Standards Policy Committee and is the English language version of EN 22768‑1:1993 General tolerances — Part 1: Tolerances for linear and angular dimensions without individual tolerance indications, published by the European Committee for Standardization (CEN). It is identical with ISO 2768‑1:1989 published by the International Organization for Standardization (ISO). This standard supersedes BS 4500‑3:1973, which is withdrawn.

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.

Foreword

In 1991, the International Standard ISO 2768‑1:1989 General tolerances — Part 1: Tolerances for linear and angular dimensions without individual tolerance indications was submitted to the CEN Primary Questionnaire procedure.

Following the positive result of the CEN/CS Proposal, ISO 2768‑1:1989 was submitted to the Formal Vote.

The result of the Formal Vote was positive.

This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by October 1993, and conflicting national standards shall be withdrawn at the latest by October 1993.

According to the CEN/CENELEC Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, United Kingdom.

NOTE The European references to international publications are given in annex ZA (normative).

Introduction

All features on component parts always have a size and a geometrical shape. For the deviation of size and for the deviations of the geometrical characteristics (form, orientation and location) the function of the part requires limitations which, when exceeded, impair this function.

The tolerancing on the drawing should be complete to ensure that the elements of size and geometry of all features are controlled, i.e. nothing shall be implied or left to judgement in the workshop or in the inspection department.

The use of general tolerances for size and geometry simplifies the task of ensuring that this prerequisite is met.

This European Standard was approved by CEN on 1993-04-15. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.

1 Scope

This part of ISO 2768 is intended to simplify drawing indications and it specifies general tolerances for linear and angular dimensions without individual tolerance indications in four tolerance classes.

NOTE 1 The concepts behind the general tolerancing of linear and angular dimensions are described in annex A.

It applies to the dimensions of parts that are produced by metal removal or parts that are formed from sheet metal.

These tolerances may be suitable for use with materials other than metal.
Parallel International Standards exist or are planned, e.g. see ISO 80621) for castings.

This part of ISO 2768 only applies for the following dimensions which do not have an individual tolerance indication:

linear dimensions (e.g. external sizes, internal sizes, step sizes, diameters, radii, distances, external radii and chamfer heights for broken edges);
angular dimensions, including angular dimensions usually not indicated, e.g. right angles (90°), unless reference to ISO 2768‑2 is made, or angles of uniform polygons;
linear and angular dimensions produced by machining assembled parts.

It does not apply for the following dimensions:

linear and angular dimensions which are covered by reference to other standards on general tolerances;
auxiliary dimensions indicated in brackets;
theoretically exact dimensions indicated in rectangular frames.

2 General

3 Normative references

4 General tolerances

4.1 Linear dimensions

4.2 Angular dimensions

5 Indications on drawings

6 Rejection

BS EN 22768-1:1993

General tolerances - Tolerances for linear and angular dimensions without individual tolerance indications

Current, Under Review

Published:

15 Nov 1993