Patent ID: 8529828

Claim:
A rotor shaft for use in a molten metal pump, the rotor shaft comprising: graphite; an annular, outer surface; a diameter; a first end for connecting to a coupling that couples the rotor shaft to a motor shaft; and a second end for connecting to a rotor of the molten metal pump, the second end having threads for being threadingly received into an opening in the rotor; wherein the first end of the rotor shaft is comprised of graphite, includes a vertically-extending keyway formed in the annular, outer surface, the keyway comprising a groove that is ⅓ or less the diameter of the rotor shaft, the groove configured for receiving a projection attached to and extending from an inner wall of the coupling, whereby the projection can apply driving force to the rotor shaft through the keyway; and wherein the rotor shaft is configured to be removed from the coupling in order to replace the rotor.