A Dumb Noob Question About Rotary

Most of the hobby lasers and their main boards are set up for X-Y movements, with the Z axis being pretty much ignored, unused, and never connected. Since these boards do have Z axis outputs, the thought pops into my tiny brain that instead of using the Y axis to control rotary movements (involving disconnection and reconnection elsewhere of the Y-axis cable), why could one not use the Z-axis output for the rotary unit?

Are there conventions within G-Code that would prevent this? Would Lightburn support doing this? And, of course, if it is possible, how would one go about making it work?

I don’t see any reason why this couldn’t be made to work. However, certain vendors may have specific rotary modes rather than relying on generic processes.

To set this up.

GRBL side:
Make sure Z-axis entries are configured correctly for purpose ($112, $122, $132). You will likely need to disable homing as well.

LightBurn side:
Enable rotary in LightBurn. Configure to Z axis. Set rotary parameters. Test proper rotary behavior.

One thing to be careful of is that since Y-axis will still be active you’ll want to make sure you don’t get any inadvertent movements. You may want to have the rotary out of the machine when you first try this.