Abstract: A unique two piece rotor construction and method of fabrication is disclosed. The rotor is cast in split positions (bifurcated along a central plane) by a shell molding or high pressure green sand technique. The portions have special pairs of interfitting mating faces, at least one being generally radially directed and at least one being generally axially directed. After the cast portions have said interfitting faces machined to a predetermined finish, and cleansed. The portions are assembled in a fixture with flux and braze material between said faces. The assembly is heated in a controlled atmosphere furnace to complete the brazed bond between said faces.