Is there any reason I should not use an XY-GMOS board wired to the PWM output on the BlackBox x32 controller to run my DC motor spindle? I've hooked it up and it works using the M3 Sxxxx command to adjust spindle speed however I have not tried cutting anything yet. I just don't want to release any magic white smoke!
Not familiar with it, if you could post more details. DC spindles often come with a combination PSU/speed controller that had horrendous isolation and often backfed the PWM input - burning out controllers - not sure if this is better, but basically you are on at-your-own-risk so decide if you trust the spindle speed controller to not do bad things
Just to clarify, I don't know much about circuit boards and my first time posting to the forum. I got an old Inventables CNC Router from a friend for free. It originally ran on an Arduino Uno and a gShield v5b with an XY-GMOS mosfet board to control the spindle. I tried to add some limit switches and I did not make things go well i.e. I did some very bad soldering... So I now have your x32 control board, all hooked up with limit switches, that is working well! I want to keep the original spindle (see pics) for now. When you say "backfed", do you mean current could be sent back to the control board? Sorry for being green.
Looks like an optocoupler near the input terminals, so maybe - but untested, third party, sadly stays your call.