Abstract: A collet type work driver for holding and driving a workpiece which is located between work centers upon a grinder, lathe or similar machinery, is disclosed. The work driver includes a unique free-floating collet package which rotates essentially free from contact with the remaining components of the work driver. Radial positioning forces are thus eliminated and existing workpiece eccentricities are automatically accommodated. The work driver can be rapidly loaded and unloaded and can have a significant effect upon production rates. The collet package portion is loosely retained within the work driver during idle periods and will not be lost or damaged. Uniform gripping action by means of the work driver eliminates workpiece deflection and surface marking and enables the device to be used with very fragile and brittle workpieces.