Patent ID: 7695227

Claim:
A threaded fastener for attachment to a workpiece by the friction stirring of a portion of the fastener into the workpiece, comprising: a base having an underside adapted to seat upon the workpiece, and a top side, said base having a hex shape to enable gripping by a hex socket for high speed rotation of the base; a threaded fastener portion attached to the top side of the base; an anchor ring of hollow cylindrical shape projecting from the underside of the base and adapted to be rotated and advanced at high speed and inserted into the workpiece upon friction stirring of the workpiece by the anchor ring, said anchor ring having an enlarged foot portion that is connected to the base by a narrow-waisted portion, thereby forming indented regions in which the friction stirred material of the workpiece becomes embedded to thereby anchor the anchor ring in the workpiece upon cooling of the workpiece.