Abstract: A stress coining fastened joint, for minimizing stress concentration in a wall of an aperture in a metallic structural member, the tool being a rigid elongated shaft adapted for forcible insertion through the aperture. The shaft has end portions and is provided with a plurality of different diameter, annular protuberances spaced intermediate the end portions. The largest of the protuberances has a diameter of such predetermined relationship to the diameter of the aperture, that upon a forced insertion thereof through the aperture the material forming the wall of the aperture is displaced radially substantially the difference between the diameter of the largest protuberance and the diameter of the aperture. The displaced material will thereafter rebound approximately one-half of the initial displacement. The stress coining tool may be combined with a conventional fastener to provide a simultaneous stress coining and fastening operation.

Abstract: A riveted joint employing a rivet having a cylindrical shank and a head with a conical undersurface, flared uniformly outwardly from the shank and truncated by an upper surface that is generally similar to the minor portion of a filled torus, sliced normal to its centerline. When being installed in a workpiece aperture to form the joint, the rivet head cold-flows to assume adequate expansion into the aperture while becoming generally flush to the workpiece surface so rivet head shaving is not required.