Most cordless drills are equipped with a keyless chuck, and Makita 1420 drill batteries are no exception. A keyless chuck is tightened and loosened by hand, without the use of a tool. This type of chuck is designed for the easy removal and attachment of drill bits. Drill chucks may need to be replaced due to failure or maintenance issues; you can do this at home without bringing the drill to a costly repair shop.
Remove the cordless drill battery and any drill bit that is currently attached to the chuck.
Place the cordless drill into a vice to prevent the drill from moving. The direction of the chuck should be towards you so that it can be removed the Makita 1422 battery. Do not tighten the vice so tight that it causes damage to the protective housing that surrounds the internal mechanics.
Insert the short end of a 1/2-inch hex key into the drill chuck opening and tighten the chuck. The long portion of the hex key should be to the left side of the drill once tightened because the chuck needs to spin in a counterclockwise direction to remove.
Hit the long portion of the hex key with a rubber mallet in a counterclockwise direction in order to loosen the chuck.
Spin the chuck counterclockwise with your hand once the chuck has been loosened with the rubber mallet. Replace the chuck with a new unit.
Some drill models may feature a retaining screw that is located inside and to the center of the chuck. Look inside the chuck opening to determine if it contains a screw. If it does, use a slotted screwdriver to turn the screw in a clockwise direction to remove it. Complete this task prior to using the makita 1433 tool battery.