Revised Standard from Last Update.

NATIONAL FOREWORD

This Indian Standard (Part 1) (Third Revision) which is identical with ISO 2901 : 2016 ‘ISO metric trapezoidal screw threads - Basic and design profile’ 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 harmonized with ISO Standard by adopting ISO 2901 : 1977 and ISO 2901 : 1993 respectively. The third revision of this standard has been undertaken to align it with the latest version of ISO 2901 published in 2016. The major changes in this revision are as follows:

a) the phrase “maximum material profiles” has been replaced by “design profiles”;

b) the reference IS 7008 (Part 4) has been replaced by IS/ISO 5408 : 2009;

c) the symbols have been updated;

d) the definition of basic profile has been deleted; and

e) Figure 2 has been revised and Fig. 3 has been deleted.

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

Part 2 Pitch diameter combinations

Part 3 Basic dimensions

Part 4 Tolerances

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 beread as ‘Indian Standard’.

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