An improved apparatus and method for fabricating a composite disc brake rotor. In accordance with this invention, a composite rotor having a stamped center section and a cast or forged braking face portion is mounted onto a press which produces a central axially deflected "bubble" of metal. The formation of such a bubble causes radially inward straining of the material defining the rotor center section which has been found to substantially reduce surface waviness and imperfections in the surface. Such improvements in flatness of the rotor center section provide accurate positioning of the rotor braking when mounted on the vehicle for improved brake performance and life. Following the step of producing the center bubble, a subsequent operation is used to blank out a center mounting hole and clearance holes for wheel mounting studs.