Method of cold forming a self-attaching female fastener element

摘要

A method of cold forming a self-attaching female fastener ( 20 ) which includes deforming a fastener blank ( 120 ) having an annular pilot, ( 122 ) an annular flange ( 128 ) surrounding the pilot and a groove ( 132 ) in the flange having cylindrical walls and annular protrusions ( 152, 154 ) on the flange and pilot, then deforming the protrusions toward each other to form an annular re-entrant groove ( 32 ) having relatively inclined arcuate walls.