Hammer Drill: Chuck Slips

Over time, and with use, the chuck will wear and start to slip. When this occurs, it is time to replace the chuck. You may want to remove the handle to make it easier. Open the chuck all of the way and insert the proper screwdriver into the chuck to remove the chuck screw at the bottom. This screw is reverse thread. Insert a large allen wrench in the chuck and tighten the chuck against the allen wrench. If the hammer drill has a gear box, set it to the lowest setting. Strike the allen wrench with a hammer to loosen the chuck. Once the chuck is loosened, unthread and remove it. Thread new chuck on the hammer drill all of the way. Now, open the chuck jaws and insert the allen wrench and hand tighten. Reinsert the screwdriver and install and tighten the chuck screw. Reattach the handle, if you removed it.

Old, worn out drill bits will slip inside the chuck as the chuck jaws will not be able to grip the drill bit properly. Check your drill bits for wear. If this only occurs with certain drill bits, and not all of them, then replace your worn drill bits with new ones.

The key inserts into the hole, located on the side of the drill chuck, then locks into the gear on the drill chuck. When turning this key, it moves the gear on the chuck, which will open or close the drill chuck jaws. Make sure you are using the correct size chuck key to lock in the gear, allowing the jaws to open or close. Over time, the chuck key can wear and may need to be replaced.

If left unmaintained, the jaws inside the chuck may not tighten all of the way, or evenly, due to debris caught inside. Open the jaws all of the way and clean out with a parts cleaner and dry thoroughly. Once dry, spray a little bit of dry lube into the chuck and then run the jaws closed and open a few times to work the dry lube into everything.