Hi, I'm new here.

I am planning to add stepper motors to a Chester Cobra / SiegC1 lathe with a view to experimenting with CNC and creating a 3D printer. (I don't have space for a larger lathe or for a lathe + a 3D printer).

I haven't seen it explained anywhere how to set the lathe tool tip reliably and accurately at a known distance from the centre of revolution of the lathe - I think this is the X0 position.

I can imagine putting a piece of silver steel in the chuck and moving the tool until it is touching the bar. One would then know that the tool was half the diameter from the lathe centre line.

But you can't do this if you want to change a tool after you have a piece of material in the chuck.

I suspect there is a blindingly simple solution but I haven't figured it out?

What is the proper procedure for establishing a known position on the X axis?

Thanks

...R