A lap joint clamp is a type of clamp used to join two pieces of sheet metal together. It is made up of two flat plates that are connected with a hinge at one end and a screw at the other. The plates are held together by the screw, which is tightened until the two plates are tightly secured. The clamps are used in a variety of applications, such as joining two pieces of sheet metal, sealing a pipe joint, or reinforcing a corner joint. They are commonly found in the automotive and construction industries.