Q about adding powered cross slide as an attachment to a large wood lathe

Hi
Stepper motors are driven via electronic drivers that are driven by 'step' and 'direction' inputs. The direction pin is either on or off, on giving one direction and off giving the other direction. The voltage used is normally 5v, the standard for logic circuits, though 3.3v is making headway in modern stuff.

The step pin is pulsed at varying frequency to give varying speed of rotation. A computer (or other control device) gives the right frequency and number of step pulses to make the motor turn the right number of steps to go the programmed distance. Stepper motors cannot instantly accelerate so they have to start slow and ramp up to speed.

So, what you need is a device that produces variable frequency pulses from the position of a knob, a switch to select which axis the pulses go to, and a switch to select the direction of the selected axis. (BTW lathes use X-Z axes, the spindle being equivalent to the spindle on a mill).

So, here is the pulse generator
555 stepper pulse generator - Electronics-Lab
and now all you need is your local electronics guru to wire it up with switches to your stepper drivers.

The stepper drivers will need 5 volts for the logic section, and 24 to 40 volts for the motors themselves, depending on the driver itself. Read about stepper motors https://www.geckodrive.com/gecko/images/cms_files/Step Motor Basics Guide.pdf for the details on why the motors run on high voltage (despite the label saying 2 volts or so!).

As for dust, there are various methods of creating 'bellows' to cover the leadscrews, and you should definitely be rigging a vacuum hose to the tool holder to suck up the dust at the source, primarily for your health, secondarily to preserve the machine. If you can use a tool that cuts rather than scrapes (like the skew chisel and gouges do) then you get much less dust.