You might want to change the chuck on your drill for any number of reasons. If you own an older drill, you may want to add a keyless chuck for convenience or replace a broken or rusted chuck. If you have a newer drill, you could add a keyed chuck for extra bit-gripping strength. These guidelines’ll help you replace your drill chuck.
Step 1. This step loosens the screw inside the chuck. Open the chuck all the way — if you see a screw inside, it’ll need to come out before you can remove the chuck. If there’s no screw inside, you can skip steps one and two.
Step 2. If there’s a screw inside the chuck, typically the threading will be left-handed, so turn it clockwise to remove it. Be careful, and use the right size screwdriver — you don’t want to strip the screw.
Step 3. Insert the largest hex key that you have into the chuck, short-side-in, and tighten the chuck. Tap the hex key sharply in a counterclockwise direction to loosen the chuck. Now you can remove it by hand.
This won’t work for every consumer drill ever made, but pretty close. Most drills will match one of two common chuck-threading standards: 3/8″-24 threaded mount for 3/8″-capacity drill chucks, and 1/2″-20 threaded mount for 1/2″-capacity drill chucks — but on some drills just the opposite may occur. To be safe, always check the thread count before you buy a replacement drill chuck.