Rolling threads on a lathe?

I suspect it's not possible or practical for most materials on most lathes due to the high forces required.

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.

Possibly have a look here

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).

Wolfgang

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 threads. ERS