Abstract: Method and apparatus are disclosed wherein a required threaded hole is formed in a hydroformed part with a single tool while the part remains in a hydroforming die cavity. In forming the threaded hole, a hole is first pierced in the wall of the part and then an annular region of the part extending about the hole is extruded inwardly to form an integral tubular neck defining a hole of predetermined depth. The hole is then expanded in a sizing operation to a diameter determined by the required thread to be formed therein by material displacement and the required thread is then formed in the wall of the hole in a material displacing manner.

Abstract: A pair of self-aligning non-pinching hydroforming dies have fingers and slots which are operable during closure of the dies on a tubular part to effect precise alignment of the dies as they are pressed together to form a hydroforming cavity about the part so that the part is not pinched between mating surfaces of the dies during their closure on the part. The fingers are further capable of mechanically straightening and/or bending the part, if need be, to prevent pinching of the part during die closure. The fingers are also capable of mechanically forming a round tubular part to a non-round cross-section region of the die cavity as the dies close to help form the part as well as prevent pinching of this section. With all such mechanical forming operations by the action of the fingers on the part performed prior to the hydroforming of the part in the die cavity.