A Diaphragm chuck is based on the principle that a thin plate may be faced to become dish-shaped. The plate (called a diaphragm) is round. Its outer rim, which is thicker than the diaphragm, is fastened to the applied to the center of the plate causes it to take the shape of a dish. The part is then ierted between the jaws and the force actuating the diaphragm is removed, allowing the now prestressed jaws to clamp the part firmly. Reapplication of force to the diaphragm unclamps the jaws, freeing the part.