Sliding ends on bar, pipe, and L-clamps can adjust to the length of a big workpiece before exerting pressure. They're commonly used in woodworking assembly to keep joins secure as glue dries. Before tightening, bar clamps have clamp ends that glide along a flat metal bar. Pipe clamps are made up of individual movable components that can be installed on any length of pipe to form a clamp. L-clamps have a sliding mechanism that regulates both length and pressure, as well as a bend in the bar that forms a secure termination.