Abstract: Plywood sheets are used to make structures such as beams, stress skin panels, boxes and tanks with the aid of special metal flanges which engage and form bonds with opposite faces of the plywood sheets along one or more edges of the sheets. The metal flanges define U-shaped grooves the sides of which become bonded to the faces of the plywood during assembly of the structures by serrations or other projections which press into the wood along the entire length of the grooves.