Abstract: A universally-movable machine part includes a disc member having a disc shaft and a recessed slot defining a bearing surface conforming to a smooth cylindrically-curved plane. At least one planar vane member defines a lower bearing surface conforming to the smooth cylindrically-curved plane of the disc slot so as to be pivotally slidably mated therewith. A rotor member having a rotor shaft defines a groove which establishes a plane passing through a geometric center point of the device and in which an upper portion of the vane member is accepted so as to be pivotal within the established plane. The rotor member also defines a lower surface upwardly and outwardly divergent relative to the geometric center point of the device to permit the rotor member to be pivotally movable about an axis mutually perpendicular with the axis defined by the disc shaft and the axis about which the vane member pivots so that the rotor member will also be pivotally movable together with the vane member.