Blind threaded fastener forming technique

摘要

A simplified method for producing internally threaded blind fasteners includes cold forming of the thin deformable walls of the fastener into bowed out sections by reverse extrusion to form deep grooves, and subsequent further cold forming to increase the diameter of this thin walled portion of the fastener to form it into bowed out sections. Three or more or even five or more sections may be formed, to increase the "pull-out" resistance by increasing the "footprint" of the deformed sections of the blind fastener.