A torque wrench is used where the tightness of screws and bolts is crucial. It is typically used on small parts such as bolts, nuts, screws and small gears. Piano preparation involves only screws or bolts. Bolts are very closely related to screws. The fasteners are commonly called "line head screws". The Pozidriv was patented by GKN Screws and Fasteners in 1962. Holding all this together were thousands of bronze screws and copper rivets. These planks were held together by thousands of copper rivets and bronze screws. Joints are secured with screws and angle plates. It can be fastened with glues, screws, and nails. The compressor itself was mounted to a steel shaft with twelve set screws. Common tools for driving screws include screwdrivers and wrenches. The bonnet typically screws into or is bolted to the valve body. Cement board is hung with corrosion resistant screws or ring-shank nails. The frame is mounted vertically on a horizontal base provided with levelling screws.