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IS0
I N T E R NAT1 O N AL O R GAN I Z AT1 O N F O R STAN DAR DI ZAT I O N
I SO RE COM MEN DATION
R 406
INSCRIPTION OF LINEAR AND ANGULAR TOLERANCES
1st EDITION
December 1964
COPYRIGHT RESERVED
The copyright of IS0 Recommendations and IS0 Standards
belongs to IS0 Member Bodies. Reproduction of these
documents, in any country, may be authorized therefore only
by the national standards organization of that country, being
a member of ISO.
For each individual country the only valid standard is the national standard of that country.
Printed in Switzerland
Also issued in French and Russian. Copies to be obtained through the national standards organizations.
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BRIEF HISTORY
The IS0 Recommendation R 406, Inscription OJ Linear and Angular Tolerances, was drawn
up by Technical Committee ISO/TC 10, Drawings (general principles), the Secretariat of which
is held by the Association Suisse de Normalisation (SNV).
Work on this question by the Technical Committee began in 1951, taking into account the
studies which had been made by the former International Federation of the National Standardizing
Associations (ISA), and led, in 1961 to the adoption of a Draft IS0 Recommendation.
In December 1961, this Draft IS0 Recommendation (No. 493) was circulated to all the
IS0 Member Bodies for enquiry. It was approved, subject to a few modifications of an editorial
nature, by the following Member Bodies :
Australia
Hungary Portugal
Austria India
Republic of South Africa
Belgium Ireland
Spain
Bulgaria Israel Sweden
Czechoslovakia Italy Switzerland
Denmark
Japan Turkey
Finland Netherlands
United Kingdom
France New Zealand U.A.R.
Germany Norway U.S.A.
Greece Poland U.S.S.R.
Yugoslavia
Two Member Bodies opposed the approval of the Draft:
Canada
Romania
The Draft IS0 Recommendation was then submitted by correspondence to the IS0
Council, which decided, in December 1964, to accept it as an IS0 RECOMMENDATION.
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TABLE OF CONTENTS
Introductory Note .
4
1 . Definitions .
2 . Inscription of the components of a linear dimension .
2.1 Tolerances shown by IS0 symbols .
2.2 Tolerances shown in figures .
2.3 Symmetrically disposed tolerance .
2.4 Limits of size .
2.5 Limits of size in one direction .
3 . Order of inscription of the deviations . 6
4 . Units . 6
4.1 Units of the deviations .
6
4.2 Number of decimals .
7
5 . Tolerances on drawings of assembled parts .
5.1 Tolerances shown by IS0 symbols .
5.2 Tolerances shown in figures .
6 . Tolerances on angular dimensions .
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ISOlR 406 - 1964 (E)
IS0 Recommendation R 406 Decem ber 1964
INSCRIPTION OF LINEAR AND ANGULAR TOLERANCES
INTRODUCTORY NOTE
For uniformity, all the linear dimensions given in this IS0 Recommendation are in metric units.
It should be understood that inch wits could equally well have been used without prejudice to
the principles established.
1. DEFINITIONS
+$
'1
O
O
4 t
-t
T = Specified tolerance
O = Zeroline
Straight line to which the deviations are referred, T
...