Thread rolling is widely accepted as the fastest and preferred method of economically producing uniform smooth, precise threads of superior physical qualities. Thread rolling utilizes hardened steel rolls to produce external threads. The working surfaces of the rolls have a thread form which is a mirror image of the thread to be produced. In penetrating the surface of the blank, the rolls displace material to form the thread roots, and force the displaced material radially outward to form the thread crests.
Advantages of thread rolling:
Cold working of metal during the thread rolling process improves the thread form physical characteristics and mechanical properties. When the material is rolled, the structure is deformed creating the thread and improving the surface hardness. The increased surface hardness results in thread form properties that are superior to those of original material.
Roll threading also improves the finish of the threads. Smooth flanks of rolled threads provide better surface contact with mating threads. The burnished roots and flanks are free of chatter, tearing or cutter marks that can serve as a focal point or stress and starting point for fatigue failures.
Rolled threads maintain consistently closer tolerances and uniformity than a cut thread. Thread rolling is unique in its ability to maintain accuracy of the original set up during long runs of high-speed production. Tooling does not change appreciably during the life of the rolling dies; they do not wear like other types of threading tools.
Roll threading material is more eco-friendly by using less material than thread cutting. There is less material used during thread rolling, which will reduce cost of the threaded rod and offer savings to the customer.