Flush riveting is a way of connecting two pieces of sheet metal together, using rivets whose heads do not protrude above the surface of the metal. In aircraft construction, a flush rivet reduces drag, thus increasing aircraft performance. This World War II-era Walt Disney industrial-training film teaches four methods of flush-riveting aircraft aluminum sheet metal: the Countersink method, the Double Dimple method, the Pre-Dimple method, and the Combination Pre-Dimple and Countersink method. The choice of method to use is based upon the thicknesses of the top and bottom metal sheets.
—yortsnave