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UDC 621.ôô2.11.6
IS0
I NT ERN AT1 ON AL ORGAN IZATl O N FOR STAND AR D I Z AT1 O N
IS0 RECOMMENDATION
R 272
HEXAGON BOLTS AND NUTS
WIDTHS ACROSS FLATS, HEIGHTS OF HEADS,
THICKNESSES OF NUTS
METRIC SERIES
2nd EDITION
February 1968
This second edition supersedes the first edition
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 212, Hexagon bolts and nuts - Widths across flats, heights of heads,
thicknesses of nuts, was drawn up by Technical Committee ISO/TC 2, Bolts, nuts and accessories, the Secretariat
of which IS held by the Deutscher Normenausschuss (DNA).
Work on this question by the Technical Committee began in 1953 and led, in 1959, to the adoption of a
Draft IS0 Recommendation.
In June 1960, this Draft IS0 Recommendation (No. 383) was circulated to all the IS0 Member Bodies for
enquiry. It was approved by 22 Member Bodies. Five Member Bodies opposed the approval of the Draft.
The Draft IS0 Recommendation was then submitted by correspondence to the IS0 Council, which decided,
in September 1962, to accept it as an IS0 RECOMMENDATION.
BRIEF HISTORY CONCERNING THE 2nd EDITION
The Secretariat of Technical Committee having drawn up a draft proposal for the revision of
IS0 Recommendation R 272, Hexagon bolts and nuts - Widths across flats, heights of heads,
thicknesses of nuts - Metric series, circulated it to Technical Committee Menibers. The draft
proposal was approv
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