The shank is electrically conducted to the metal workpiece through the chuck and table,
the LED lights up and the beeper sounds(only for 6566-3E),
when the ball touches the workpiece
Not suitable for rotary use. Hardened shank and contact ball
Hardened shank and contact ball

Dynabrade 95843 Dynabrade Air Lube 10W/NR, 1 Gallon
3M 45099, Roloc Disc Pad TR, Medium 1-1/2 in 1/4-20 Internal, 7000045280 
