rotation axis instead of Y axis

hi everyone,

i have a 3 axis machine and want to add a lathe/rotation axis, too but i can't add it as 4th axis because of the control card so i am thinking i can add it instead of Y axis.

so what i gonna do is unplug y axis connection from control card and plug new rotation axis cable.

so i need the gcode to have rotation axis values instead of Y axis ones, i assume i need to set it from "post-processor generator" window (when click edit for current PP) and under setup tab but couldn't make it work. any help on it?

thanks in advance.

If you do that, how are you going to keep your Y axis stable? Once it's no longer coupled to a motor that's locked in place, it will drift when affected by cutting forces.

i will keep driver loaded, just gonna cut the signal from controller so it wont move.
even if i leave it unloaded, i ma not sure if there is enough cutting force to move it.

So you've got 4 drivers, but only 3 communication channels? What kind of machine is this, and what CNC control software are you using? RhinoCAM won't have a problem generating code for X, Z, and A axes (assuming you've got the Expert level or higher) but this is something you're going to have to set up in the control software for it to work.

it's 3 axis, have a chinese control card, link of card is here RZNC-0501,RICHNC,RichAuto-Beijing Richnc Technology Co.,LTD - RZNC-0501,RICHNC,RichAuto-Beijing Richnc Technology Co.,LTD
some local guys buy parts, build them and sell, i bought it second hand. and it looks like this https://img.letgo.com/images/42/d0/9...c05075ea3.jpeg

i don't have a 4 drivers really, i will buy new driver and stepper and lathe parts, not sure about their english name. the boards itself has outputs labeled x, y, z and c. so i wired a driver and stepper (small ones like 3d printer parts) and send a gcode for 4 axis generated by rhinocam. and the new stepper i connected to c axis worked synchronized with y axis. i am assuming it's set like that to use double stepper/servo for y axis and high possible it can be fixed by firmware but i don't have the original setting for firmware and don't wanna mess with it. so thinking it's best way for me to send 4th axis gcode as y axis and make the trick by disconnecting the real y axis from controller.

i am not at expert level or close, most likely self-learner. i was cutting some basic stuff with cnc at school years and that's all. no professional works at all.