The thread rolling is basically a cold-forging process that forms the entire length of an external thread by displacing the bla^E. material. Threads are produced on the blanks of predetermined diameter by a rolling action under pressure and between two rotating cylindrical steel roll dies whose working faces are suitably threaded. This action plastically deforms the blank in such a manner that a portion of the blank metal is displaced to form the root of the thread and raised in unbroken fibw-flow lines to form the crest of the thread.
The roll dies rotate synchronously on parallel or slightly tilted horizontal spindle shafts that are adjustable by sliding laterally. The dies are made of special steel alloy with an exceptional hardness and toughness resulting in maximum wear resistance. The blank is placed on a carbide tipped work rest blade or center support disposed between the dies and after a complete cycle v/ of approach, rolling and release of the hydraulically operated
right hand spindle shaft the rolled thread is removed. The blank is placed in the rolling position, either by hand or automatically. A timer built into the machine release the hydraulic pressure on the roll dies when the required diameter is completed and returns the right hand spindle head to its starting position.