a roller assembly for use in gravity roller and power roller conveyors , especially those used in sanitary applications such as for food processing and the like . the roller assembly prevents contaminants from entrapment within the roller or associated parts and may be repeatedly washed or steam cleaned without corrosion or degradation . preferably , wear - resistant , corrosion - resistant , organic , polymeric plastic , bearing inserts are axially and rotationally retained by retaining means within openings in the opposite ends of a corrosion - resistant roller . at least one of the roller end opening or the insert at each end includes a bottom wall closing off the roller interior and providing a thrust resisting surface . preferably , the inserts receive stainless steel support shafts which have rounded ends engaging the bottom wall to resist axial thrust on the roller . in the preferred form , the bearing inserts have curved , shaft - engaging surfaces to facilitate and maintain low - drag , rotational support even when the roller is deflected during loaded operation .