Abstract: A workpiece holding assembly is operable in combination with a machining apparatus, such as a grinding or milling machine, for presenting a workpiece to a cutting tool of the machining apparatus in various different angular positions in order to adapt the machining apparatus for producing undercut areas, such as dovetail-shaped slots, in the workpiece. The workpiece holding assembly includes a base which is mountable on a machining apparatus, a gimble which is rotatably mounted on the base, a mounting assembly for securing a workpiece on the gimble and a drive assembly for automatically rotating the gimble to tilt the workpiece. The workpiece holding assembly is preferably utilized in combination with a machining apparatus of a type having a computerized numerical control, and it is preferably adapted to be interconnected with the computerized control for automatically controlling the rotational movement of the gimble.