NATIONAL FOREWORD

This Indian Standard (Part 3) (Fifth Revision) which is identical with ISO 4032 : 2012 ‘Hexagon regular nuts (style 1) — Product grades A and B’ issued by the International Organization for Standardization (ISO) was adopted by the Bureau of Indian Standards on recommendation of the General Engineering and Fasteners Standards Sectional Committee and approval of the Production and General Engineering Division Council.

IS 1364 was originally published in 1960 and first revised in 1967. Subsequent to the publication of 1967 edition, many changes had been agreed upon at international level which have been reflected in IS 1367 series of standards covering ‘Technical supply conditions for threaded steel fasteners’. Accordingly, second revision was published in 1983 splitting the standard into 5 parts covering hexagon head bolts, hexagon head screws, hexagon nuts, hexagon thin nuts (chamfered) and hexagon thin nuts (unchamfered).

The third revision of this standard was published in 1992 by adoption of ISO 4017 : 1988. The fourth revision was made by adoption of ISO 4032 : 1999 in 2002.

In 1967 version of this standard, the widths across flat dimensions for Ml0 and Ml2 size fasteners were specified as 17 mm and 19 mm respectively. However, in the 1983 version, these widths across flat dimensions were brought in line with ISO 4032 : 1979 and specified as 16 mm and 18 mm respectively for Ml0 and Ml2 size fasteners. Recognizing the difficulty of immediate changeover to new width across flat dimensions, the Committee decided to permit width across flat dimensions as per 1967 version, that is, 17 mm and 19 mm for Ml O and M12 size fasteners till 31 December 1994. Now it is expected that the entire fastener industry would have switched over to new width across flat dimensions and from 1 January 1995 no old width across flat dimensions shall be permitted.

This fifth revision of this standard has been undertaken to align it with the latest version of ISO 4032 : 2012.

The text of ISO standard has been approved as suitable for publication as an Indian Standard without deviations. Certain terminologies and conventions are, however, not identical to those used in Indian Standards. Attention is particularly drawn to the following

a) Wherever the words ‘International Standard’ appear referring to this standard, they should be read as ‘Indian Standard’.

b) Comma (,) has been used as a decimal marker, while in Indian Standards, the current practice is to use a point (.) as the decimal marker.