Hanger bolts are double ended fasteners with a wood screw on one end and a machine screw on the other. A hole needs to be pre-drilled for the wood screw side. They are perfect for knockdown furniture as the machine screw end accepts a standard nut that be easily removed. Furniture with two sided wood screws cannot be disassembled and reassembled without stripping out the hole. Hanger bolts are commonly used in the assembly of bed frames or to attach table legs.