Effect of number of fasteners on the strength of corner joints for cases

Tests were carried out in order to determine the bending strength of 457-mm-(18-in.-) wide case joints constructed with multiple fasteners. Both dowels and screws were included in the tests. Results indicated that bending strengths increase rapidly until the zones of influence of the fasteners overlap. No increase in strength was obtained beyond that point. Screw length was found to have a greater effect on strength than diameter. In the case of dowel joints, it was found that because ofthe adhesive added to the joint area, joints could be constructed that exceeded the bending strength of the board itself.