A molding die structure for forming oblique teeth on a rivet nut includes a mold seat, a first forging die, a second forging die, and a retaining member. The mold seat is provided with a mold cavity and a threaded portion. The first forging die is inserted into the mold cavity and provided with a die cavity and a nut cavity. The second forging die is inserted into the die cavity and has an inner face provided with an oblique toothed portion and a guide hole. The oblique toothed portion includes a plurality of oblique teeth. The retaining member is screwed into the threaded portion and limits the first forging die and the second forging die in the mold cavity. The second forging die and the die cavity of the first forging die form a low friction contact.

A molding die structure for forming oblique teeth on a rivet nut includes a mold seat, a first forging die, a second forging die, and a retaining member. The mold seat is provided with a mold cavity and a threaded portion. The first forging die is inserted into the mold cavity and provided with a die cavity and a nut cavity. The second forging die is inserted into the die cavity and has an inner face provided with an oblique toothed portion and a guide hole. The oblique toothed portion includes a plurality of oblique teeth. The retaining member is screwed into the threaded portion and limits the first forging die and the second forging die in the mold cavity. The second forging die and the die cavity of the first forging die form a low friction contact.

A method of permanently attaching a fastener to a plastically deformable panel includes placing a fastener shearing edge in contact with a first surface of a panel and a die assembly in contact with an opposite second surface of the panel, and penetrating the fastener shearing edge through the panel to create a hole. The fastener shearing edge is driven into a swage formed as a recess in an end face of the die assembly to deform the fastener shearing edge outwards along the swage and into contact with the second surface of the panel. A bent portion of the panel is trapped between the deformed fastener shearing edge abutting the second surface of the panel and a tapered flange formed on an outer surface of the fastener that abuts the first surface of the panel. A die assembly and driving mechanism for attaching the fastener is also provided.

A method of permanently attaching a fastener to a plastically deformable panel includes placing a fastener shearing edge in contact with a first surface of a panel and a die assembly in contact with an opposite second surface of the panel, and penetrating the fastener shearing edge through the panel to create a hole. The fastener shearing edge is driven into a swage formed as a recess in an end face of the die assembly to deform the fastener shearing edge outwards along the swage and into contact with the second surface of the panel. A bent portion of the panel is trapped between the deformed fastener shearing edge abutting the second surface of the panel and a tapered flange formed on an outer surface of the fastener that abuts the first surface of the panel. A die assembly and driving mechanism for attaching the fastener is also provided.

Method for manufacturing a clinch nut, comprising: cold forging a steel body including a weight percentage of carbon comprised between 0.15% and 0.25% inclusive to form a workpiece including a pliable section designed to deform into a crimping bead and a connection section, applying a heat treatment to the workpiece, and tapping the connection section to form an internal thread.

An apparatus to produce a self-piercing and clinch nut includes a first forging die assembly, a second forging die assembly, a third forging die assembly, a transfer mechanism, and a controller. The first forging die assembly subjects a blank to first processing. The second forging die assembly is adjacent to the first forging die assembly, and subjects the blank, which has undergone the first processing in the first forging die assembly, to second processing. The third forging die assembly is adjacent to the second forging die assembly, and subjects the blank, which has undergone the second processing in the second forging die assembly, to third processing. The transfer mechanism transfers the blank between two adjacent forging die assemblies among the first to third forging die assemblies. The controller controls operations of the first to third forging die assemblies and the transfer mechanism.