Abstract: A holding jig (1, 2, 3) for a thin cylindrical work (W) includes a holding member (10, 10A, 10B) which holds the work (W) from an inner peripheral side and a diameter changing unit (25, 27) which changes a diameter of the holding member (10, 10A, 10B). The holding member (10, 10A, 10B) is made of metal and has a cylindrical shape and an elastically expandable or contractible diameter. The holding member (10, 10A, 10B) is configured with an outside diameter of the holding member (10, 10A, 10B) being held smaller than an inside diameter of the work (W) at the time of insertion into an inner periphery of the work (W) and being expanded after inserted into the inner periphery of the work (W) to hold the work (W) from an inner peripheral side of the work (W) with an outer peripheral surface in close contact with an entire inner peripheral surface of the work (W).

Abstract: A workholding apparatus including a body and a drive member carried by the body, so that the drive member and body partially define a fluid chamber therebetween for containing a fluid. A driven member is also carried by the body and includes multiple displacement reliefs therein. An intermediate member with a displacement relief is received between the drive and driven members. The intermediate member prevents the drive member from extruding through the displacement reliefs in the driven member under fluid pressures of the fluid, thereby enabling use of the apparatus under higher performance applications that would not be possible without the intermediate member.