If the screw is cold worked then you start with wire, that is upset and broached and then the threads are rolled. The whole part is cold worked not just the threads.
Michael B. Connelly, FASM, CQE
I did some FA work on set screws and the client was trying to replace a domestic producer with overseas that was "not working" in application - the US producer had a specialized method of rolling the tip of a stainless steel set screw to cold work hardened -as I was able to confirm via micro indentation hardness testing.- the overseas producer had no idea and simple machined them from pre-hardened (heavily drawn) stainless steel barstock (Free machining to boot!) - that caused obvious thread rolling issues - yes thread rolling a free machining steel - story gets even deeper.
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