Drill screw and die for producing same

摘要

A drill screw is produced by a pinch pointing die comprising a pair of substantially identical drill point forming portions each of which includes a half conical recess, a half cylindrical recess and a half truncated conical recess. The drill screw thus produced comprises, therefore, substantially identical two half drill point portions each of which includes a half conical portion, a half cylindrical portion and a half truncated conical portion.