IS/ISO 9960 : PART 1 : 1992 Draughting Instruments with or Without Graduation - Part 1 : Draughting Scale Rules

NATIONAL FOREWORD

This Indian Standard which is identical with ISO 9960-l : 1992 ‘Draughting instruments with or without graduation - Part 1 : Draughting scale rules’, issued by the International Organization for Standardization (ISO) was adopted by the Bureau of Indian Standards on the recommendation of the Optical and Mathematical Instruments Sectional Committee (LM 20) and approval of Light Mechanical Engineering Division Council.

The requirements of draughting scale rules were earlier covered in IS 1482 : 1985 ‘Metric scales for use with drafting machines (second revision)‘, which was first published in 1960 and subsequently revised in 1970 and 1985. The present revision has been published out as a dual number standard with IS0 9960-l : 1992. IS0 9960 has been published in 3 parts covering draughting scale rules, protactors and set squares. Corresponding Indian Standards on these subjects are IS 1482 : 1985, IS 1563 : 1989 and IS 1561 : 1989, respectively. While IS 1482 : 1985 has been revised as a dual number standard with IS0 9960-l : 1992; the Optical and Mathematical Instruments Sectional Committee, decided not to revise IS 1561 and IS 1563 as these standards are more relevant for the Indian Industry.

Some of the important changes in the present revision of IS 1482 are:

1) Scales, having oval, semioval and triangular sections, in addition to flat section have been incorporated.

2) Length of division lines have been modified.

3) The shape and dimensions of working edge have been included.

4) The geometrical tolerances, namely straightness tolerance of working edge, flatness tolerance of the underside of the scale rule and parallelism tolerance between the two working edges, have been specified.

5) Scale rule of widths 50 mm and 40 mm in addition to 45 mm in respect of certain nominal lengths have been included and tolerances on width have been further reduced.

These scales are to be used with draughting machines conforming to IS/ISO 9962-2 : 1992 ‘Manually operated draughting machines - Part 2 : Characteristics, performance, inspection and designation’ which replaces IS 2287 : 1970.

IS 1482 : 1985 will stand withdrawn after publication of this standard.

The text of ISO Standard has been approved as suitable for publication as Indian Standard without deviations. Certain 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 0) has been used as a decimal markerwhile in Indian Standards the current practice is to use a point (.) as the decimal marker,