An F-clamp is a simple mechanical device used for holding materials together. The name comes from its "F" shape. The F-clamp is similar to a C-clamp in use, but has a wider opening capacity. An F-clamp may also be called a bar clamp or speed clamp. This tool is used in woodworking while more permanent attachment is being made with screws or glue or in metalworking to hold pieces together for welding or bolting.
An F-clamp is also a simple mechanical device used for lifting engine or transmission parts. The clamp has an adjusting screw to tighten onto the part and a lifting ring to attach a hoist cable.
F-clamps in the industry terminology have the jaws mounted on a flat bar, while a pipe clamp, which has the same construction, is mounted on a pipe, normally of 1/2" or 3/4" diameter.