So I did this… connected the board to the (M4 Router Be Gone (installed the spindle))
and copper-taped the bottom of it, soldered a big bare ground wire to it, ran it down to and through my vacuum hose to earth ground. (I know… janky looking but its fine. I have a better clamp on order for this connection between the hose and the ground wire)
I then ran some gcode pockets for 100mm circles, 100mm squares all cutting from 3 to 6mm deep – about 30-40 minutes of cutting and didn’t get a single error. not a long enough session to claim victory, but I’m slightly encouraged by it.
I did notice that the sled does tip a bit on movement, which hurts accuracy on the corners / turns. I have over 20% slope on this so I’m thinking I’ll wax the bottom when I care more. Right now I am after consistently not ruining wood vs perfect accuracy 
