Thread Rolling, Mainly, of a Hollow Tube

Abstract

Assuming that thread formation by rolling is a kind of indentation which is continuously and repeatedly impressed on the blank by a die, the writer has measured the relation among the indentation of a die which is statically impressed on the blank, the grooves cut on the blank by a rolling die and the height increase of screw threads generated by the rolling die aling the grooves of the threads, and introduced a formula with consideration of the relations between the rolling pressure and the number of rotations of the die required for the complete formation of the threads. This paper explains the thread rolling of a hollow tube without a mandrel under a proper rolling pressure, and shows how the abovementioned formula coincides with experimental results.