Revised Standard from Last Update.

NATIONAL FOREWORD

This Indian Standard (Part 4) (Third Revision) which is identical with ISO 2903 : 2016 ‘ISO metric trapezoidal screw threads — Tolerances’ 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.

This standard was originally issued in 1973 and subsequently revised in 1988 and 1999. The first and second revisions were made by adoption of ISO 2903 : 1977 and ISO 2903 : 1993 respectively to keep it in line with the ISO standard. The third revision of this standard has been undertaken to align it with the latest version of ISO 2903 : 2016.

In this revision, Clauses 1, 13 and 14, and Table 7 of last version have been technically revised (now Clauses 1, 11 and 12, and Table 5).

This Indian Standard is published in 4 parts. The other parts of this series are:

Part 1 basic profile and maximum material profile

Part 2 pitch diameter combinations

Part 3 basic dimensions

The text of ISO Standard has been approved as suitable for publication as an Indian Standard without deviation. Certain terminologies and conventions are, however, not identical to those used in the 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 decimal marker, while in Indian Standards, it is current practice to use a full point (.) as the decimal marker.