To Install a bit: Select a bit based on the thickness of line you want to make, then insert the flat end into the opening of the chuck (about 1/4 inch); Next, insert the allen key into the screw on the side of the chuck and tighten the screw until it holds the bit firmly in place.
Replacement tips for Beadsmith Micro Engraver. You will receive a set a 2 diamond coated tips.