Dave - I had a near miss yesterday - I was turning a lid for a spalted Bradford Pear box, using the 5" diameter Grizzly 4-jaw chuck. Going high speed to get a good finish, and swept the speed control to zero too quickly. That chuck does not have grub screws, so it unscrewed from the lathe spindle, and luckily went flying off the backside at 2000 rpms. It hit my corrugated plastic back splash, and change direction right towards me. I dodge, and it hit floor and rolled into more stuff. So, Fastenal in Franklin has my order for the 6mm x 12mm setscrews, and a 6mm tap, to be picked up on Monday.