Tips on Repairing a Drill
If the chuck on the drill has been torn or broken, use a screwdriver to loosen its middle screw. Once the screw is out, remove the chuck, and use the screw to secure the new chuck in place.
Before attempting to repair a drill, determine which kind of casing it has. A clamshell casing is the most difficult to repair. When removing the screws from a clamshell casing, you must take care not to disturb the parts inside the drill. A drill with a component casing is easier to fix because all of its components are in individual compartments. When repairing any type of drill, create a wiring diagram so you'll be able to reconnect all wires correctly when you reassemble the tool.