Description: Self-centering hinge drill bit set allows for quick bit changes without rechecking the need for tools. You just need to disassemble the screw and replace the drill with a new one. Perfect for hinges, handles, drawer slides, woodworking. Feature: 1. Fits most general purpose electric drill bits (all center drill shank diameter is 6mm) 2. Efficient and accurate positioning 3. 135° bevel blade drill 4. Double-sided sawdust design 5. The drill bits are surrounded by spring-loaded drivers that have a window to show the drilling depth while making adjustments Disassemble: 1. Prepare a center drill and an Allen key 2. Insert the Allen key and turn it 3. Grasp the top of the drill bit and unscrew the shell (like turning the lid of the drink) 4. Assemble the parts. If you need to replace the drill, you just need to remove the broken bit and install the replacement bit. Too fast speed will be out of the middle, break the bit or jam - When drilling the hole, you can adjust according