Patent ID: 7681773

Claim:
A friction stir welding apparatus comprising: a first assembly comprising a bore therethrough, said bore defining an inner diameter; and a second assembly comprising a welding end, a first portion of said second assembly including said welding end extending through said bore, a second portion of said second assembly comprising a substantially cylindrical surface that is adjacent said inner diameter, said substantially cylindrical surface comprising material control threading arranged along a line substantially parallel to said second assembly; and said inner diameter-comprising a smooth surface such that rotation of either said first assembly or said second assembly and said material control threading will cause plasticized material from a welding process that has entered an area between the cylindrical surface and said inner diameter to move towards a welding zone located proximate said welding end of said second assembly wherein the second portion is discrete from the first portion and wherein the material control threading is surrounded by the smooth surface of the inner diameter.