A rivet is a permanent mechanical fastener. A rivet is often produced in mild steel, wrought iron, copper, aluminum (or alloy thereof) by process of forging. Before being installed a rivet consists of a smooth cylindrical shaft with a head on one end. The end opposite the head is called the tail. On installation, the rivet is placed in a punched or drilled hole, and the tail is upset, or bucked (ie., deformed), so that it expands to about 1.5 times the original shaft diameter, holding the rivet in place. To distinguish between the two ends of the rivet, the original head is called the factory head, and the deformed end is called the shop head or tail.
RIVETING
For riveting parts to be joined are first drilled with the help of a drilling machine. Clearance is taken into consideration while riveting because by pressing the application diameter of the rivet is somewhat increased. Usually, clearance is considered as per following: If the diameter of the rivet, is d= 12 to 24 mm, Clearance, is C= 1.5 mm; If the diameter of the rivet, is d= 24 to 48 mm,
Clearance, C = 2 mm
Riveting is done with the help of forming die and backup die which keep a rivet in between them and by application of force rivet is set in the parts to be joined. Equal and opposite force makes the rivet deform and the tail part of the rivet is converted to the head at the bottom.
RIVETING BY HAND
Proper riveting by hand is done in the following manner:
- Remove burrs of holes.
- Align the holes.
- Place the rivet through the plates to be joined.
- Support the head of the rivet with a dolly.
- Press plates together with a rivet set.
- Hammer the rivet shank vertically to spread it out.
- Hammer it round to shape nearly to the required size of the head.
- Finally, finish the head by using a rivet snap.
RIVETING BY MACHINE
Riveting can also be done by using pneumatic hammers, handheld squeezers, or by using riveting machines. There are different types of riveting machines. Each type of machine has unique features and benefits.
An example of machine riveting. This is called orbital riveting. It has a spinning forming tool (known as a peen) which is gradually lowered into the rivet which spreads the material of the rivet into a desired shape depending upon the design of the tool. The tool is mounted at a 3 or 6° angle. The forming tool contacts the material and then presses it while rotating until the final form is achieved.
Orbital riveting machines are used in a wide range of applications including brake linings for commercial vehicles, aircraft, locomotives, textile and leather goods, metal brackets, window and door furniture, latches, and even mobile phones. Many materials can be riveted together using orbital riveting machines including delicate and brittle materials, and sensitive electrical or electronic components.