A rivet gun is also sometimes known as a pneumatic hammer. It is used to install rivets which are a form of joint in various carpentry and metal work projects. They work by hammering the large head end of a rivet into a hole at such a force that the tail, or narrow end, is flattened out to fill the hole it was initially placed in. The force is large in all rivet guns, but especially ones that are pneumatically powered. Rivet guns themselves can vary in shapes and sizes, like a pneumatic pop rivet gun versus a simple blind rivet gun. They also come with a variety of handles, all of which are suitable for different uses. The aforementioned pneumatically powered ones also come with a regulator so that the amount of air that enters the tool can be controlled. The user then controls this with the trigger in the handles. It activates the piston which works back and forth to hit the rivet head that then works in conjunction with the bucking bar to flatten the tail of the rivet.