An apparatus and method is provided for producing a piston assembly for use in a fluid translating device such as a hydraulic pump or motor. In the subject arrangement, a piston is provided having a cavity at one end thereof and a slipper having a spherical head portion which is precisely positioned within the cavity to provide a space therearound and subsequent thereto a plastic material is formed in the space to maintain the spherical head portion in the cavity. This arrangement eliminates the sliding friction that exists in other piston assemblies and furthermore reduces the precise sizing of the cavity relative to the spherical head portion.