stepper motor like a spindle

I use a stepper motor for тхе 4 /lathe/axles - A. How can I set it to rotate constantly and independently of the other axes - X Y Z, like a spindle. The problem is when I use G2 G3 code and at the same time I have to rotate axis A.

Hi, here is the easiest way I know of doing it, use an Arduino to continuously send pulses to the stepper driver. Use an input pin on the Arduino to turn on and off the pulses. Now you just need to configure your HAL file to turn the “spindle” on and off. There’s certainly a way to do this without extra hardware, but that’s how I would do it with my limited coding experience.

You won’t be able to do it with a G Code or M code without making some changes to your HAL file.

Would G33 help? linuxcnc.org/docs/html/gcode/g-code.html#gcode:g33 Hmm... Now that I think about it, not sure if there's any way to use that with a G02 or G03. I've only used it with linear moves on x and z on a lathe to cut tapers. (Edited) ..and now I re-read and see you wanted independent motion. Sorry... A 555 timer circuit could make the pulses too.

Stepgen has a velocity mode, maybe this is what you could use.
linuxcnc.org/docs/2.8/html/man/man9/stepgen.9.html

Not a lot of info on velocity mode tho.

Arduino and 555 solve that, but I looking for a software solution via linuxcnc configuration.

Running a stepgen in velocity mode will do this (and support velocity ramp-up, ramp-down etc)