What is a Rivet?
The term rivet is used to describe a variety of fasteners with a couple of common traits. They are pre-shaped at one end and have their other end reshaped when they are put to use. All have a smooth shaft that passes through the materials being bonded. They are used to join two or more materials together and form a joint that is stronger and tighter than a screw of the same diameter could be.
Rivets have been used to make watertight hulls on ships, high-pressure tanks for steam boilers and refineries, gussets for bridges, airtight skins on airplanes --- even used to bind heavy fabrics like denim that could not be easily sewn.
Hot Iron, Cool Results
The best known type of rivet, the hot rivet, provides the strongest joints. In this process, glowing hot rivets are fed through precisely-drilled holes where the unformed end is hammered to close the joint. As the rivet cools, it contracts and squeezes the joint tightly together.
The squeeze exerted by the rivet is spread across the joint, increasing the friction between the joints and making them less likely to move. All rivets, hot or cold, exert some lasting pressure on the joints they form.
Better than Bolts
Because the shaft of a rivet is smooth, it is better at resisting side-to-side motion (called shear) than a screw or bolt of the same diameter. Consider a screw and rivet passing through two pieces of metal; 100 percent of the rivet is in contact with the metal, while the screw touches half or less.