scope:

GENERAL: Prevailing torque type locknuts, as defined for this standard, are all metal, one piece locknuts which spin on freely until the locking element engages the mating part. These nuts must be wrenched to final position. They will lock in any position on a bolt providing the locking element is fully engaged by the bolt threads. Prevailing torque locknuts do not depend on the bolt being loaded for locking action.

The locking feature will consist of three constrictions equally spaced or two constrictions diametrically opposed. The constrictions usually appear on the top of the conical surface, though two constrictions on the upper portion of the flats diametrically opposite are permissible.