Abstract: A milling system is disclosed for creating a cavity in a bone. The cavity has a cross section which has a generally triangular profile having a first side generally parallel with an axis of the bone and a second side forming an acute angle with the first side. The cavity is contiguous with a pre-existing conical cavity in the bone. The system comprises a drive shaft, a frame for carrying a cutter and a cutter for cutting the cavity. The drive shaft has a proximal end configured for coupling to a drive means and a distal end configured to form a portion of a drive joint for coupling the drive shaft to a cutter. The frame includes a shaft and a cutter mount for mounting a cutter at a first angle approximating the acute angle with respect to the shaft. The mount includes a bracket extending laterally from the shaft to a bearing configured to receive a portion of a cutter and maintain the received cutter oriented at the first angle during rotation.