Splined hubs and shafts transfer torque in mechanical power transmission systems and protect shaft assemblies from wear. They consist of an involute splined shaft with grooves and teeth that match a hub or coupling. As the shaft rotates, the locking grooves move the hub or coupling and transfer torque. This power transmission relieves stress on the shaft assembly and extends component life spans. Splined hubs and shafts are also used with radial bearings in clutches. Combined with a bearing, the splined hub and shaft’s multi-tooth design transmits power at high torque levels and speeds.