Drilling Bits, Collets and Chucks

A chuck is a specialized type of clamp used to hold an object with radial symmetry, especially a cylinder. In a drill or a mill, a chuck holds the rotating tool; in a lathe, it holds the rotating workpiece. Chucks commonly use jaws to hold the tool or workpiece. A collet /ˈkɒlɪt/ is a subtype of chuck that forms a collar around an object to be held and exerts a strong clamping force on the object when it is tightened, usually by means of a tapered outer collar. It may be used to hold a workpiece or a tool.