Abstract: A method and apparatus for rotatably supporting a workpiece WP includes a bearing ring 300 which extends around a center support member 204. The bearing ring is deflectable inwardly at a plurality of spaced apart locations 310 to engage the center support member at these locations during machining of a workpiece. At each of the locations where the bearing ring is deflected inwardly into engagement with the center support member, the bearing ring has a reduced thickness to thereby reduce the resistance of the bearing ring to deformation at these locations. Fluid pressure applied against the outside of the bearing ring deflects the bearing ring inwardly at the locations of reduced thickness. The deflected portions of the bearing ring engage the center support member to securely hold it during machining of a workpiece.