Firstly, this comes earthed, so no need to mess with the internals.
I wanted spindle for my Frankenstein homemade CNC / Laser unit, and didn't want to spend a fortune. Well this thing is a beast. This is my first CNC so I don't have anything to compare it with, but it cuts hardwood, softwood and multiply with ease.
3D printed a very basic dust shoe to suite a 25mm hose I had, works a treat, also got the Vevor VFD to control this spindle, wired it to the 5v output from my control boards. It only actually outputs 4.5 volts so I am running at a max of 21900 rpm so 90% power, and i cuts great