Abstract: An apparatus for the grinding or polishing of cylindrical (telescopic) or conical primary crown castings, which as tooth replacements are to be mounted in appropriate anchoring members and which have pins extending from their top sides in axial alignment with the centerlines of the castings, includes a base having a support column extending upwardly therefrom and supporting an electric motor having a shaft with a grinding or polishing disc mounted thereon and a crown casting receptacle is rotatably so supported on the base that its angle relative to the base is adjustably lockable and, locked at a given angle, it is movable toward the grinding disc for engagement of the casting with the grinding disc so as to be abraded at a desired angle the motor and grinding disc being surrounded by a shroud forming an air flow space in communication with the interior of the support column which also has a suction nozzle adapted to be connected to a suction line for the removal of grinding and polishing dust through the ai