Thread rolling dies and process for forming same

Thread forming dies to form a continuous helical thread for a metal fastener. The dies are designed and constructed to eliminate laps and discontinuities in the thread form particularly in larger diameter fastener blanks. The dies are constructed by calculating a roll-off section which tapers down to expel the threaded fastener then determining the length of a dwell section having a full depth grooves to create a well-defined and stable thread. Finally, a roll-up ramp section is calculated along which the grooves of the die become deeper along its length until reaching the desired thread angle and depth. The thread forming dies include a stationary die and a moving die. The fastener blank is rolled therebetween causing the die faces to form the thread as the blank moves from the roll-up section, through the dwell section and out the roll-off section.