Both.Do I simply start and stop the spindle from the Mach 3 screen Spindle icon as well as speed control?
Or will the G-code file (I use RhinoCAM) start it for me for both start and speed setting.
If you just want to start it, you can click the spindle on/off button.
If your g-code has an M3 in it, then that will also start the spindle.
Same with rpm. You can enter it on the screen, or let the g-code change the speed with the S word.