Male threaded fastener capable of use with a swaged collar

摘要

A male threaded fastener has a plurality of impressions on the nonload-bearing flank of the thread that receives material swaged from a collar to lock the collar and pin together and increase the breakaway torque of the collar. The impressions have a depth of about 0.1 to about 0.3 of the depth of the thread from root to crest. The thread is free of impressions at least 1.5 pitch lengths from its ends.