An extrusion cross-section for a straight edge clamping device including (a) an elongated hollow base having a constant cross-section; (b) a first stop fixed at one end of the base; (c) a second stop movably provided along the base; and (d) a clamp for holding the workpieces together, includes a) a flat base portion having top and bottom surfaces, and two edges; b) two L-cross-sectioned portions having horizontal and vertical parts, facing each other, integrated with the flat base on the top surface of the flat base forming a top groove; c) two hollow portions, facing each other, integrated with the flat base on the bottom surface of the flat base forming a bottom groove; and d) two flanges having a horizontal part, vertical parts, facing each other, integrally connected to the corresponding hollow portion, wherein the cross-section has a right-left symmetry with a vertical center line as symmetry axis.