It can be done with a follow rest. And there was a roll-threading tool that
looked like a three-wheel knurling tool, although I've never seen one. There
used to be machines built for it, but they weren't general-purpose lathes. I
wouldn't want to try it, in steel, anyway, on a lathe I valued.
I don't know how they make roll-threaded stock these days, but once upon a
time they used a specialized type of lathe for the job.
At one time bicycle repair shops had thread rolling boxes for putting
the threads onto the ends of spokes. And these were hand operated!
If you look carefully you will notice that the thread O.D. is larger
than the spoke O.D.
The thread rolling box can be self contained with three rollers such
that the lathe only has to supply the torque to drive the stock.
Think of clamp-type knurling (two opposed rollers) and hand operated
knurlers (three rollers).
On Sat, 09 Apr 2011 22:02:05 -0300, Howard Eisenhauer
I know this post is pretty late but mebbe it will help. The three
roller thread rolling devices for lathes work well. They are expensive
though. And diameter control is very important as is starting surface
finish. I've used these devices for production runs of special
stainless steel screws. The diameter needing to be held within close
tolerance is pretty obvious but bad surface finish may not seem so bad
until you start making threads. Too coarse a finish translates into
poor diameter control and a torn finish leads to flaking of the
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