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

3M 45099, Roloc Disc Pad TR, Medium 1-1/2 in 1/4-20 Internal, 7000045280
3M 28473, Roloc D/F Cool Running Disc Pad TR, 4 in x 5/8-11 Internal, FIN, 7000144107
3M 22333, Cloth Belt 577F, 120 YF-weight, 3/4 in x 20-1/2 in, Fabri-lok, Full-flex, 7000119441, 200 per case 
