Patent ID: 8662372

Claim:
Friction stir welding apparatus, comprising: a shoulder tool; a pin tool rotatable within the shoulder tool, the pin tool and the shoulder tool independently rotatable and coaxial with respect to one another; a spindle housing; first and second coaxial spindle shafts respectively connected to the shoulder tool and the pin tool, the first and second coaxial spindle shafts independently rotatable with respect to one another, the first spindle shaft surrounding the second spindle shaft; a first motor surrounding and directly connected to the first spindle shaft and adapted to rotate the shoulder tool; and a second motor surrounding and directly connected to the second spindle shaft, the second motor arranged concentrically and coaxially with the first motor along a common axis in the spindle housing, the second motor slideably mounted for linear movement along the common axis within the spindle housing, and adapted to rotate the pin tool.