Abstract: A method of attaching a female element having an annular riveting portion to a panel and the installation apparatus. The method includes driving a punch through the female element into a panel supported on a die member forming an unsupported cone-shaped panel portion in the cavity of the die member. The punch includes an axially extending piercing end which pierces a small opening in the cone-shaped panel portion and an arcuate drawing portion which is driven against and through the panel opening, enlarging the panel opening. The annular riveting portion of the female element is then driven into the cone-shaped panel portion and through the panel opening, drawing the panel portion into a tubular shape engaging the external surface of the riveting portion. Finally, the riveting portion is driven against a center post of the die member, radially outwardly deforming the free end of the riveting portion and forming a mechanical interlock with the tubular panel portion.

Abstract: A method of attaching a metal fastener, such as a stud-bolt, to a panel. The fastener includes a self-piercing annular projecting wall defining a recess having a bottom wall and an inner side wall defined by the annular wall. The method includes locating the fastener adjacent a panel with the self-piercing end portion facing the panel opposite a die member. The fastener is then forced toward the die member, such that the annular wall pierces a slug from the panel into the central recess and against the bottom wall. The die member simultaneously deforms the distal end of the annular wall outwardly and the pierced panel edge is deformed from the plane of the panel against the external surface of the annular wall, interlocking the panel and fastener.

Abstract: A self-piercing fastener, such as a stud bolt, for attachment to a panel or the like. The fastener includes a fastener portion, such as a threaded shank, and a self-piercing and riveting end portion. The end portion includes a central recess enclosed by a self-piercing and riveting wall on at least opposed sides of the recess. The wall has an internal surface terminating in a sharp piercing edge at its distal end which is adapted to pierce an opening in the panel. The recess terminates in a bottom wall which is preferably spaced from the piercing edge of the wall a distance greater than the thickness of the panel.