Accurately formed critical tolerance fit components are provided for fluid dynamic bearing motors, including disc drive memory systems. In an aspect, critical tolerance fit components are molded to a metal insert and include a portion of a hub, a disc seating surface, and a disc locating surface. The insert includes another portion of a hub, a sleeve, or a disc clamp retainer for a novel disc clamp. In an aspect, the plastic component is situated to cause the thermal expansion of the plastic to be restricted by the thermal expansion of a metal insert. Expensive machining of a stamped metal hub is minimized or eliminated by using the molded component portions. Strict component tolerances are provided as needed for perpendicularity relative to motor rotation for seating a disc with accurate flatness, a circumferential surface for centering the disc, and tight parallelism between a disc mounting surface and a center shaft.