A short metal pin or bolt for holding together two plates of metal, its headless end being beaten out or pressed down when in place.
Rivet pin: The pin is the main body of the rivet which will slot through the pieces of material being joined together.
Rivethead: The head will sit on the outside of the material to stop the rivet from sliding out of the material.
Rivet mandrel: The mandrel is slotted into the rivet gun when it is fastened. The rivet gun pulls the mandrel partially through the pin (body) of the rivet, deforms the pin to form a second head, and then snaps the mandrel off.
Rivet mandrel head: The mandrel head expands the body of the rivet then leaves itself buried inside the rivet, creating a second head to secure and fasten the pieces being joined.