Description

This Standard specifies requirements for single start parallel coarse pitch series metric screw threads, mainly intended for threaded fasteners. It covers screw threads from 1.6 mm diameter up to and including 64 mm diameter, in tolerance classes 6e, 6f, 6g and 8g, for external threads; and 6H and 6G for internal threads.

Information is given on symbols for screw thread parameters, tolerances, deviations, thread classes, designation and verification.

Appendices, giving notes on the production of screw threads and a comparison of symbols used in this Standard and the 1972 edition, are included.

It should be particularly noted that in this edition, the thread roots of external threads (root curvature and associated limits and tolerances), are specified in a manner that is fundamentally different from the 1972 edition.

Scope

The standard gives information on symbols for screw thread parameters, tolerances, deviations, thread classes, designation and verification.

Appendices are included giving notes on the production of screw threads and a comparison of symbols used in this standard and the 1972 edition.

Notes:

1. The coarse pitch series given in this standard comprises the 1st and 2nd choice diameter/pitch combinations (for coarse pitch series threads) extracted from AS 1721. They are the same as those given in ISO 261 and ISO 262; the latter covering diameters up to and including 39 mm only.
2. For information on the bases of the metric screw thread system and associated formulas, see AS 1721.