Abstract: A method of joining a pair of elongated triangular-shaped pieces together by clamping includes the steps of bringing a pair of opposed face platens together to a predetermined thickness which is the thickness of the ultimately desired composite pair. A sliding edge platen is forced against the pair at a pressure sufficient to cause the two triangular-shaped pieces to slide relative to each other against a fixed edge platen to adjust for width and in order to bring the outer side faces of the pair into a substantially parallel relationship. At the end of the curing cycle the pressure is released from the face platens and sliding edge platen allowing them to move apart to their retracted positions and the composite pair may then be removed from the clamping system. A multi-opening clamping system has a plurality of individual clamping mechanisms mounted about the periphery of a rotating cylindrical frame.