7 Machine parts, namely, bearings, belts, brakes, bushings, camshafts, chains in the nature of chains for conveyors, driving chains other than for land vehicles, transmission chains other than for land vehicles, roller chains being parts of machines, shaft clamps, clutches, shaft collars, couplings, hand cranks, drum dials for making machine adjustments, drive chains, gears, gear boxes, gear drive belts, gear racks, handles in the nature of knurled handwheels, pin hubs, clamp hubs, gear lever knobs for machines, lead screw, leveling mounts, linear ball slides, linear roller slides, pressure rollers, pulleys, retaining rings, transmission shafts other than for land vehicles, shaft adapters, shaft extensions, shaft hangers, shaft wipers, shaft seals, springs, chainwheel sprockets, cam sprockets, stud mounts, threaded inserts, timing mechanisms in the nature of cam sprockets and chains, timing belts, ratchet and pawls