What is Thread Rolling?

Thread rolling is a chipless cold forming process. A plain cylindrical blank, with a diameter part way between the major and minor diameters of the finished thread, is rotated and squeezed between cylindrical type hardened steel dies whose working surfaces are the reverse of the thread form to be produced. The thread of the die penetrate the surface of the blank as it rolls between them, displacing meterial to form the roots of the threads, and forcing the displayed material radially outward to form the crests. Unlike other threading process, no material is wasted. Most threads are rolled by the in-feed method in which the entire thread length is formed simultaneously without axial movement of the part. Threads that are too long to be produced by the in-feed method can, however, be rolled by a thrufeed method on these type of machines.