Purpose:

This standard provides recommended dimensional data for screw thread undercuts for straight ‘MJ’ metric screw threads in accordance with AS1370.

Application:

The thread undercut data included in this standard are primarily designed to provide a clearance for threading tool runout either where the thread is in a blind hole or where the thread is close to an adjacent shoulder. These thread undercuts are not recommended for bolts, screws or studs which are required to be necked, e.g. reduced shank contiguous to the thread, to improve their tensile, impact and cyclic load performance.