METHOD AND APPARATUS FOR ASSEMBLING A SCREW AND COMPRESSIBLE WASHER

摘要

A method and apparatus for assembling a screw and an axially compressible washer and rolling threads on the screw blank in a single operation that results in a shank configuration immediately beneath the head of the screw that allows complete compression of the washer. The method involves assembling a washer on the blank and retaining it thereon while the washer and screw assembly are subjected to swaging forces from opposing reciprocating thread rolling dies. The washer is retained on the blank in such a manner as to allow the thread rolling dies to swage an upper section of the blank and thereafter move the washer upwardly directly adjacent the head in a single thread rolling pass.