A centerless work-holding apparatus or fixture for a machine tool for holding work in a working position radially and axially relative to a reference axis with work-driving by use of rolls and an axially and rotatably movable rotor element which is fluid-actuated for releasably clamping the workpieces during work thereon. The rotor element has a flange which provides areas on opposite sides thereof for actuating it with fluid under pressure. These areas are individually greater than the profile area or transverse dimensional area of the workpieces so that very small workpieces can be individually held by the pressure of the fluid actuating the rotor element.