Installation die for self-attaching fastener

摘要

A pierce nut having a central pilot, a cylindrical flange portion surrounding the pilot and a groove in the flange portion having at least one inclined side wall and a bottom wall having a convex annular protuberance preferably comprising spaced arcuate protuberances extending around the pilot which deforms panel metal beneath the inclined side wall and providing anti-rotation means when the nut is attached to a metal panel. The outer groove side wall includes radial notches or grooves which receive panel metal to provide anti-torque means. The improved die button includes an annular lip having an inside piercing edge spaced from the end to pierce a smaller slug and an annular convex fillet which deforms more panel metal into the nut groove to form a secure mechanical interlock between the nut and panel.