Abstract: A disposable carbide cutting blade assembly for a universal rotary molding cutter head. The assembly comprises a disposable carbide blade blank having its cutting surface contoured to the desired configuration, a smooth rear, bottom, and front surface, and a hole extending through the carbide blade blank. The carbide blank is positioned against a steel backer plate, which in turn is provided with a ledge for supporting the carbide blank from below, and a smooth front surface against which the rear surface of the carbide blank rests when in position. A safety pin protrudes from the front face of the steel backer plate, and extends into the hole within the carbide blank to properly seat the carbide blank against the steel backer plate. The rear surface of the steel backer plate is provided corrugations along its entire height for mating with the corrugations on the inner wall of a slot of a universal rotary cutter head.