Patent ID: 7013550
Filing Date: 2006-03-21
Classification: B21K,Y10T

Abstract:
1. A method of making self-piercing nuts comprising the steps of: firstly and preliminarily pressing into a closed mold a raw parallelepiped metal piece so as to provide a nut blank that has in an upper region thereof a generally square pilot portion with a generally square end face capable of piercing a metal panel, the nut blank having in a lower region thereof a pair of flanges that continue sideways from opposite side walls of the pilot portion; secondly coining the nut blank to form a pair of ridges facing one another and extending along and integral with upper edges of the opposite side walls of the pilot portion; thirdly pressing the nut blank within an open mold so that the pair of ridges are swaged sideways and outwards to form shoulders in such a fashion that a lateral groove is formed in each of the opposite side walls and intermediate between each shoulder and one of the flanges facing it; fourthly boring a rough hole axially through the pilot portion; and finally tapping a female thread in the inner periphery of the rough hole.