A lower tool frame is used in manufacturing a plurality of convertible roofs. Structural roof parts are disposed in the lower tool frame upside down with respect to their use position. Forward connection parts are provided for selectively connecting the forward end of the convertible roof to a windshield frame and rearward connection parts are provided for attaching the rearward end of the convertible roof to a vehicle body. A single upper tool frame is lowerable onto the lower tool and is used to position the forward and rearward connection parts with respect to the structural roof parts. The single upper tool frame is used to assemble all of the convertible roofs for a series of vehicles.