Electronic gearbox with linuxcnc

Hello,

I am configuring now my control box with mesa 7i76e.
I have a manual lathe that was converted to cnc, currently with trapezoidal screws.
I still do manual turning and I need to keep that function. Right now I have an ABZ encoder on the spindle, so I would like to do some software gearbox even without a gcode program running.
I just want the leadscrew to turn at a specific speed proportional to spindle speed, and change the feed rate somewhere in the software from 0.1 to 0.01/rev.
From what I've inspected so far, linuxcnc seems quite flexible so I have the feeling this could be done.
Can anyone give any thoughts on this so that I can dig deeper and see how to actually get this done.

This is an old post but it since this shows up as the first hit on Google here is my config to do exactly what the poster wanted to do:

forum.linuxcnc.org/47-hal-examples/38233...arbox-mode-for-lathe

Awesome, can’t wait to try it!
I scrolled a bit the code from my phone browser, and I have a question, does it works with metric leadscrew?
If not I will have to make a fork and add a pull request after trying it.
Thanks!

vmihalca wrote:

does it works with metric leadscrew?

Of course. You have to customize Z, X and A scale values for your machine no matter what since it's very unlikely you will have the same setup I have an imperial lead screw and cross slide but my .hal and python code is all mm internally.