Abstract: An elongated shaft suited to a molten metal environment which forms a connection between a rotor and an impeller. The shaft being formed with at least one end, in cross-section, having a plurality of rounded side portions with a relatively large radius and rounded corners having a relatively small radius connecting the side portions.

Abstract: A post for a molten metal pump having an end joined to a hole in a pump base. The post end includes a longitudinal bore opening at the end of the post and a port opening to the side of the post intersecting the bore. A plug is inserted into the bore above the level of the port yet leaving a portion of the upper bore open. Cement can be injected into the bore and out the ports. Thereafter, a second plug can be inserted into the bore to drive cement out. To remove the post, it is cut across its longitudinal axis to expose the open upper portion of the bore. The opening is a pilot hole to drill a longitudinal hole in the post. A device having two members connected by a rod are attached to the upper and lower surfaces of the remaining post, respectively and tightened to break the cement joint.

Abstract: A drive system for impeller shafts includes a coupling that has a universal joint that is lubricated under all operating conditions. A housing is connected to the universal joint, which housing includes a hollow end portion adapted to receive the non-threaded end of an impeller shaft. A threaded stud projects from the end of the shaft and into the housing where the stud is secured by means of a nut. The nut is readily accessible to the user so that the axial position of the shaft can be adjusted without difficulty. The nut is releasably held within the housing so that the shaft and stud, with nut attached, can be quickly disconnected from the coupling. The invention also includes a modified "square drive" configuration for the ends of the shaft that is extremely strong and enables the shaft to be connected to the impeller and the coupling very easily.