AS 1721-1985 (R2017)

Abstract

Specifies requirements for single start parallel metric screw threads having the ISO basic profile for triangular screw threads, covering the size range from 1 mm diameter to 355 mm diameter inclusive. Provides for a coarse pitch series, a fine pitch series and a constant pitch series, the latter intended for use in applications for which either the coarse or fine pitch series are unsuitable. Gives information on screw thread parameters, tolerances, deviations, thread classes, designation and symbols. Appendices are included giving the basis of the tabulated values, guidelines (with examples) for calculating the limits of size of untabulated screw threads and notes on the production of screw threads.

RECONFIRMATION NOTICE
Technical Committee ME-029 has reviewed the content of this publication and in accordance with Standards Australia procedures for reconfirmation, it has been determined that the publication is still valid and does not require change.
Certain documents referenced in the publication may have been amended since the original date of publication. Users are advised to ensure that they are using the latest versions of such documents as appropriate, unless advised otherwise in this Reconfirmation Notice.
Approved for reconfirmation in accordance with Standards Australia procedures for reconfirmation on 16 June 2017.
The following are represented on Technical Committee ME-029:
Association of Accredited Certification Bodies
Association of Wall and Ceiling Industries of Australia
Australian Chamber of Commerce and Industry
Australian Engineered Fasteners and Anchors Council
Australian Industry Group
Australian Steel Institute
AUSTROADS
Bureau of Steel Manufacturers of Australia
Galvanizers Association of Australia
Materials Australia
National Association of Steel-Framed Housing
National Association of Testing Authorities Australia
New Zealand Heavy Engineering Research Association
Society of Automotive Engineers- Australasia
Steel Construction New Zealand
Swinburne University of Technology

Scope

This standard specifies requirements for single start parallel metric screw threads having the ISO basic profile for triangular screw threads, covering the size range from 1 mm diameter to 355 mm diameter inclusive. The metric screw thread system comprises the following series:
(a) The ISO coarse pitch series, which gives graded diameter/pitch combinations in diameters from 1 mm to 68 mm inclusive, and is predominantly intended for commercially produced threaded fasteners.
(b) The ISO fine pitch series, which gives graded diameter/pitch combinations in diameters from 1 mm to 33 mm inclusive.
(c) The ISO constant pitch series, which gives a series of standard pitches to be associated with diameters from 8 mm to 355 mm inclusive.

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

Due to the methods adopted by ISO for rounding the tabulated values (see Appendix A), the values for the various parameters given in the tables are to be taken as authoritative for the application of this standard.

Appendices are included giving the basis of the tabulated values, guidelines (with examples) for calculating the limits of size of untabulated screw threads and notes on the production of screw threads.

NOTE: The ISO metric screw thread system, as given in this standard, does not provide for interference fit threads.

General Product Information

Published
Document Type	Standard
Status	Current
Publisher	Standards Australia
ProductNote	Reconfirmed 07/07/2017. This standard has been reconfirmed in Australia in 2017 and remains current in New Zealand. Reconfirmation Notice 07/07/2017
Pages
ISBN
Committee	ME-028
Supersedes	DR 83185