Spindle Rotation Direction

This is just a curiosity in hopes that it can work for a potential future project. I was hoping to know if the spindle has any capability of spinning in the opposite direction (CCW). I’ve tried M4 and M04 which are reverse commands, but they don’t work and the spindle still spins CW.

Does anyone have any suggestions of what to do? And is there anything that I can possibly do with the spindle driver to get both directions?

I wouldn’t try it with the servo motor as is. The shaft has no taper or keyway to engage the pulley. It is a slip fit so the only thing keeping it from spinning is the tension provided by a 5/16” cap screw. Spinning the opposite direction could loosen the screw so they may have built in a fail safe to prevent people from doing that.