- A rivet is made of two separate pieces that are joined at the base. The base of the rivet is narrow enough to pass through holes in the material being joined. A pin, attached to the very bottom of the rivet base, passes through the rivet. A rivet gun pulls this pin up. That action causes the base of the rivet to expand, thus preventing it from coming out of the hole. As the rivet expands, it pulls the collar of the rivet down while expanding the base, thus securing the fastener.
- A pneumatic rivet gun uses compressed air to grasp the rivet pin and to pull the pin upward to affix the rivet. An air compressor supplies the air used to power pneumatic pop rivet guns. In small shops, a smaller air compressor can provide adequate power. In larger installations, such as aircraft assembly lines, large compressors can provide air for a large number of pneumatic rivet guns. Pneumatic rivet guns connect to compressed air sources using air hoses and standard fittings.
- Once the gun trigger is depressed, a throttle valve allows air to flow through a pneumatic hose. The air pressure forces a rivet through the holes in the sheet metal to be joined. The air then powers teeth that grasp the rivet pin. These teeth then pull the pin through the rivet. As the pin is pulled through, the bottom of the rivet expands to permanently join the two pieces of metal. The pneumatic gun continues to pull the pin until it breaks off flush with the top surface of the rivet.
