Patent ID: 6883223

Claim:
A method of applying a self-piercing fastener to a workpiece comprising the steps of; (a) locating a punch in alignment with a setting die, the setting die being formed with a radially inner cavity and a radially outer cavity surrounding the radially inner cavity; (b) positioning the workpiece between the punch and the setting die; (c) positioning a self-piercing fastener between the workpiece and the punch; and (d) advancing the punch to drive the fastener into piercing engagement with the workpiece, the fastener thereby displacing material from the workpiece into the setting die wherein the fastener is a semi-tubular fastener having a head and a shank, the shank having a tubular portion engaging the workpiece and the head closing one end of the shank, and wherein, as the fastener penetrates the workpiece the fastener displaces a slug of material with a diameter substantially equal to the diameter of the shank of the fastener, a first part of the displaced material flowing into the radially inner cavity in the setting die and a second part of the displaced material flowing into the radially outer cavity of the setting die.