This specification gives the dimensions, tolerances, mechanical properties and performance requirements for prevailing torque steel hexagon locknuts with ISO metric coarse series threads in diameters from M3 to M36 inclusive.
Note: Appendix A extends this range up to and including M39, but it should be noted that these are non-preferred diameters.
The locknuts are intended for assembly with fasteners with external threads of thread class 6g, e.g. bolts to AS 1110, ISO Metric Hexagon Precision Bolts and Screws. Provision has been made for the supply of prevailing torque locknuts in the all-metal type and insert type in strength grades 6, 8 and 10 (see Clause 5.1).
Appendix B sets out requirements for a thin insert-type prevailing torque steel locknut. The requirements in this appendix are additional to those of the specification.
This specification is intended primarily to apply to steel locknuts and does not apply to locknuts requiring special properties such as weldability or mode of corrosion-resistant materials. In addition, this specification does not apply to the ability of all-metal locknuts to withstand temperatures above 300°C, or of locknuts with non-metallic inserts to withstand temperatures above 100°C, or of any locknut to withstand temperatures below -50°C.
Attention is drawn to the fact that these locknuts are intended primarily for use in normal engineering applications. Should prevailing torque steel locknuts for use in safety critical, and similar applications, be required, attention is drawn to Clause 7.3.
The designation 'locknut' is a generic term used to identify the internally threaded products covered by this specification. It is not intended to imply an indefinite permanency of fixing.
AS 1285:1973 history
1973AS 1285:1973 Common torque steel hexagonal lock nuts (ISO metric series)