Abstract: A method for dimpling and riveting a workpiece wherein the workpiece is clamped, the dimpling, drilling and riveting are performed sequentially while the workpiece is clamped, and the workpiece is heated prior to dimpling. During clamping a pressure foot force is applied to one side of the workpiece, and during dimpling a force is applied to the opposite side causing movement of the workpiece a small distance and against the pressure foot force. The dimpled recess in the workpiece is in the general shape of a truncated cone, and the drilling provides a rivet-receiving hole through the workpiece in the recess. When it is desired to provide a fluid-tight seal, the minor diameter of the truncated cone is made slightly greater than the diameter of the rivet-receiving hole thereby providing an annular step or ledge extending between the hole and the outwardly diverging wall of the dimpled recess.