Abstract: A friction stir welding apparatus includes a C-shaped frame having two opposing jaws which are spaced apart to define a space for receiving workpieces which are to be welded together. One of the jaws supports a rotatably driven friction stir welding spindle, and the other jaw supports a back-up tool. The spindle is supported in a polycrystalline thrust bearing disposed in the one jaw for absorbing thrust forces exerted on the spindle during a welding operation. The C-shaped frame may be an integral one-piece structure, in which case the apparatus and workpieces are relatively advanced to cause the spindle to penetrate the workpieces at an edge thereof and to carry the welding tools along a weld path to a second edge of the workpieces, where the spindle exits and disengages the workpieces.

Abstract: A process for joining two or more overlapping metal workpieces includes providing a fastener which is made of metal having a melting point temperature at least as great as that of the workpieces. The fastener is rotated about its central axis and is axially advanced at a predetermined advance rate into engagement with the workpieces so as to cause plasticization of the workpieces at the interface with the fastener, and to cause the fastener to axially penetrate through substantially the entire thickness of the workpieces. The rotation of the fastener is then stopped, and the plastic zone which surrounds the fastener cools to form a metallurgical bond with the fastener. The resulting fastened joint is mechanically superior to conventional mechanically fastened joints made by rivets and the like.

Abstract: A locking nut for use with a bolt for connecting members together. The bolt has a head and a shank. The members are disposed between the head and the nut when the locking nut connects the members together. At least a portion of the shank has external threads formed thereon. The locking nut includes a shell having a bore extending therethrough for receiving the bolt. At least a portion of a wall of the bore has internal threads formed thereon. The shell is sized and shaped to permit rotation of the nut on the bolt for tightening the nut on the bolt. The nut further includes a generally tubular insert sized for being received in the bore of the shell. The insert has a threaded portion having an outer surface with external threads for threaded engagement with the internal threads of the shell, and an inner surface with internal threads for threaded engagement with the external threads of the bolt. The insert includes a locking portion constructed for interlocking the insert with the shell.