![]() ![]() There are other high-strength "rivets" used in airframe building, including the Huck and Hi-Shear rivets, where a collar is installed on a manufactured head and shank using special tools. Blind rivets come in both round head and countersunk versions. The remainder of the stem then stays in the rivet (part of the rivet’s strength comes from the stem), sealing the rivet. After the rivet is set, the pulling force separates the stem from the rivet at a manufactured weak point in the stem. (Some people call them "pop rivets," after the sound they make when the stem separates.)Ī blind rivet is installed using a hand-operated puller or a pneumatic gun that pulls the rivet’s stem. Most of these types have gone by the wayside, but you can still find them at times, particularly when someone is restoring an older airplane and wishes to maintain the same look.Īnd there are "blind rivets," so named because they can be installed in places where it would be impossible to get a bucking bar to form the bucked head. Before the war, manufacturers used a bewildering array of rivets, including the round head (AN430), with a higher-diameter head than the newer universal head the brazier head (AN455 and AN456), with a flatter and wider head and the flat head (AN442), among others. They are identical to the older AN426 and AN470 rivets that became the standards during World War II. The two rivets we see most often are the round universal head MS 20470 and the 100-degree countersunk MS20426. When the temper and/or dimensions of an aluminum or steel sheet must be maintained, riveting is still the most common method used to join the various components. Until welded structures became more common, riveting a structure or component was the preferred method. Rivets have been in use since aviation’s earliest days. A properly installed rivet will resist tension to a lesser degree, but its primary job is to transmit loads along the piece of material, not at a major angle away from it. A rivet acts as a clamp that holds two or more pieces of material together, but its main job is to resist shear forces. Rivets resist these same forces in ways useful to those who want to build structures that will be light enough to fly but strong enough to tolerate the substantial loads imposed by the forces of flight. What you’ve witnessed is the difference between two stress forces being applied to the tape’s adhesive: Shear, trying to separate the two pieces by pulling on the ends, and tension, the motion of pulling the piece up from the table. But stick it on a surface and pull vertically and the tape comes off with comparatively little effort. Have you ever tried to pull apart two pieces of stuck-together duct tape? Tug as you may on the ends of the tape, the adhesive seems to stick to itself with a tenacity that would stymie a tractor pull. ![]()
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