Abstract: An ironing punch for ironing the socket of a ball-and-socket joint has a punch body with a plurality of circumferentially spaced ridges disposed on an outer circumferential surface thereof and extending from a distal end surface. The ironing punch also includes a plurality of ridge-shaped dies fitted respectively in recesses defined between the ridges on the punch body. Each of the ridges is ground by a single grinding wheel with the ridge-shaped dies removed from the punch body, and each of the ridge-shaped dies is also ground by a single grinding wheel. The punch body has relief grooves for preventing the grinding wheel from physical interference with junctions between the recesses and the distal end surface.

Abstract: A cup-shaped raw workpiece having a bottom panel and a cylindrically-shaped circumferential panel is positioned facing downwardly on a movable lower punch having a forming gear profile. The lower punch is provided in a die having an orifice portion which together with the gear profile defines an orifice. A resilient mechanism resists downward movement of the lower punch. An upper punch is lowered to hold the bottom panel of the workpiece against the lower punch and pushes the workpiece to extrusion form the inner surface thereof through the orifice. An escape groove for excess metal can be provided in the bottom inside corner of the workpiece at the juncture of the circumferential panel and the bottom panel. The lower punch can be provided with an upwardly extending protrusion near the outer circumferential edge of the upper end surface thereof which has an outer chamfered circumferential edge.