Any airframe mechanic must be a proficient riveter. Aluminum rivets are the most common fastener used in modern aircraft structural applications. Proper rivet installation takes practice but also requires the riveter to understand the guidelines for preparing rivet holes, selecting rivets and mechanically driving them.
Before any rivets are installed, rivet holes must be properly drilled and prepared. If replacement rivets are being installed, the holes have already been drilled in the material. These holes must still be round and free of sharp edges and burs. For new rivet installations, holes must be drilled. Ensure that the holes are drilled with proper rivet spacing (the distance from the center of a rivet hole to the center of an adjacent hole) and rivet edge (the distance from the nearest rivet hole to the edge of the material being riveted). Documentation from the aircraft manufacturer, repair facility, or FAA will dictate proper rivet spacing and rivet edge. If the rivet application requires a flat rivet head flush with riveted metal, the metal must be properly countersunk.
The correct rivet must be selected for each application and be sized correctly for each hole. Aluminum alloy rivets are suitable for most applications but vary in type and strength. Different materials, like carbon steel or titanium, are used for rivets in especially high stress areas. Different types of rivets are identified by different markings on the heads of the rivets. It is also important to know if a flush surface is needed, which requires a countersunk rivet. Protruding head rivets are allowable in many instances.
Essential tools for installing solid shank rivets are an air-powered rivet gun and rivet set and a bucking bar. Riveting in most areas of an aircraft is a two-person procedure. The riveter selects the proper rivet set (the metal die that fits into the rivet gun and impacts the rivet), while the bucker prepares with the proper bucking bar. It can take two persons to install rivets, because it very important to take care not to damage the rivet head or the surrounding material with the rivet gun. Also, the riveter is often on the outside of the aircraft with no access to the shank of the rivet where the bucker works. The bucking bar must be held against the rivet shank before riveting starts, so he must indicate that he is ready. Then the riveter presses the gun and rivet set against the head of the rivet and operates the trigger. It is important to keep the rivet set in proper contact with the rivet head. The bucker also has an important job. The formed head at the back of the rivet should be flat and round, and it should have a diameter 50-percent larger than the shank diameter with a thickness of one half of the shank diameter. Special blind rivets are used in spaces with very limited access. They are installed by one person using a special tool called a rivet puller. But solid shank rivets should be used whenever possible.