Boxford TCL125. (Fresh start )

[Doddy]

Have you decided on the control software yet? That may impact a lot of what you need to consider to rebuild the machine.

You should have guessed by now that the key to coordinatig spindle speed and axis actions some form of spindle measure/feedback. I'd expect that the TCL should have a spindle position encoder of some description - figure that out (if it can be re-used) and that should make for an easier life.

When looking at spindle speed control - my experience of trying to LinuxCNC with a closed-loop PID control to get accurate RPM (not really necessary) was thwarted by the internal filtering of the spindle controller... if I could advise anything it would be to KISS.

You've got the mechanics of the lathe already - the control system should be fairly straightforward. Happy to chat through ideas (and maybe steal some of yours).