To perform best results of Dremel 655 Router Bit Keyhole, Dremel recommend users:

• Insert the accessory bit all the way into the tool and then back it out slightly before tightening down. This provides plenty of shank for the collet or chuck to hold onto the bit.
• Secure objects to a stable surface while working.
• If chattering occurs, increase speed.
• For detailed edges on wood and soft materials.