Abstract: This invention provides a chuck for a glassworking lathe which includes a chuck body rotatable with a drive spindle nose about a longitudinal axis and a handwheel rotatable about the same longitudinal axis. A locking device is provided for releasably locking the handwheel to the chuck body for unitary rotation of the handwheel with the chuck body. A spiral gear or scroll is fixed to the handwheel to define a radially extending path of spiral movement relative to a longitudinal axis upon rotation of the spiral gear. A plurality of jaw base members include spiral gear grooves for meshingly engaging the spiral gear, are angularly spaced about the axis and are movable radially with respect to the axis upon rotation of the spiral gear engaging the gear grooves formed in the bottom of each of the jaw base members.