Abstract: An automatic or semi-automatic lathe especially useful for producing pre-determined optical surfaces on plastic contact lenses. A collet supported on the spindle of a variable speed motor supports a lens blank in coaxial alignment with the spindle. A cutter is held in a vertically adjustable tool post mounted on one of a pair of stacked stages arranged for linear movement radial and axial of the lens blank, respectively. The other stage is mounted on a carriage which in turn is mounted on the base of the lathe and arranged for linear movement radial of the lens blank. A second variable speed motor acting through a pair of cam-operated X/Y drive mechanisms supported on the carriage drives the stages to move the cutter across and into the face of the rotating lens blank, thereby generating any desired combination of concave and/or convex optically curved surfaces. In an alternative embodiment, individual variable speed motors power the X/Y drive mechanisms through sliding wedges or the like.