Drill chucks are the part of a drill in which the drill bit is encased and held in place. They are essentially revolving cylinders that are placed on the end of the drill. They usually consist of three sides, or jaws, which move in concert when the outer sleeve of the chuck is turned. Two major types of drill chucks exist, keyed and keyless drill chucks, but within these two major divisions are many sub-types, intended for a wide variety of functions.
Keyed chucks require a key to be inserted in the side of the before it can be adjusted. They can turn either clockwise or counter-clockwise.
Super Ball-Bearing Keyed Chucks
Super ball-bearing keyed chucks are equipped with small ball bearings that lessen the friction while simultaneously allowing the chuck to more effectively grip the bit.These are the most heavy-duty types of drills available, usually used in industrial settings.
Plain Bearing Keyed Chucks
Plain bearing keyed chucks are far simpler than super ball-bearing chucks. Their gearing and sleeves are all made up of one piece, so they are more durable. These chucks are usually used for medium-duty work, including stationary drilling and woodworking.
Light-Duty Keyed Chucks
Light-duty keyed chucks come in most handheld electrical drills intended for private home use. More often than not these days, keyless chucks are used in lieu of this type.
Stainless Steel Keyed Chucks
Stainless steel keyed chucks are used on drills that must be sterilized for some reason, used in such places as dentists' offices, hospitals, or in food preparation. They are identical is design to plain bearing keyed chucks.
Keyless chucks are self-tightening, designed so that they tighten when more torque is applied. Because the actual turning of the chuck is what tightens a keyless chuck, drills with keyless chucks can only be turned clockwise. Keyless chucks are all basically the same in design, but have different degrees of durability. They also come in stainless steel.
Precision Keyless Chucks
Precision keyless chucks are designed to hold smaller drill bits in place. They are often used in high-accuracy industrial settings.
Keyless Drill Chucks
Keyless drill chucks for portable drilling machines are the chucks usually found in household multipurpose drills. They usually have metal or plastic sleeves. These chucks can also be designed to allow for counter-clockwise drilling.
Keyless Drill Chucks With Integrated Shanks
Keyless drill chucks with integrated shanks are generally more durable because the chuck is integrated with the body of the drill. These types of chucks are usually used for industrial machines.