Chuck

Attachment to a turning lathe for holding work. The simplest form is a face plate, with jaws which can be ad Face Plate with Chuck Jaws in Position. justed in radial slots by screws; when these jaws are geared together so that to move one is to move them all, the chuck is self-centering; of this there are two types, the scroll and the geared. When the chuck is made more complex, so that double motions may be given to work fastened to it or by it, it may be used to turn ovals and ellipses or figures of great complexity. The self-centering type is much used to hold small round work, and for drills.