I'm new to the forum .

Member of a local model engineering club .

FWIW I have a Colchester Bantam lathe and a Rong Fu ( like a Warco ) round column mill which I have fitted with a simple CNC, retaining the handwheels – so as to have either NC or manual control.

David, Everybody,

thank-you for the interest in the RF CNC project.

I've shamelessly copied a design from YouTube driving the axes leaving the handwheels in place. With the stepper drivers switched on – you can't move them by hand. Drivers off – you feel the steppers cogging over giving slight resistance to motion. The X&Y leadscrews are replaced with ballscrews which would rotate under axial load without that resistance. I'm told that the steppers probably generate backEMF which may not be good for drivers , i haven't had problems.

 photos  are probably self-explanatory 

The Z acts on the quill. The original quill rack-and-pinion mechanism gives more backlash than i'm happy with.

Controller is GRBL running on Arduino – works very reliably – I am impressed.

Arduino step-and-direction output goes to hefty drivers bought with the stepper motors from cnc4you – works fine – photo shows all the bits – subsequently moved to proper enclosure-

In use for 5 years for shape-simple and shape-complex machining.

hope that's helpful,

johns

Edited By John Scott 13 on 27/09/2021 12:39:06