Abstract: A method of expanding a diameter of a tube includes the steps of positioning the tube with one end abutting a stop member, extending a mandrel through an interior passageway of the tube, and expanding a diameter of an expandable head connected to the mandrel as the mandrel is moved in a direction toward the stop member. The diameter of the tube expands in correspondence with the expansion of the diameter of the mandrel. A longitudinal axial force is applied to the tube in a direction toward the stop member as the expandable head expands the diameter of the tube.

Abstract: An apparatus for tapering a tube having a frame, a tube receiving end connected to the frame, a variable-orifice die arranged so as to be movable relative to the frames, and an axial tension cylinder connected to the tube receiving end so as to apply tension forces to the tube. The variable-orifice die includes a stand having a housing and a plurality of die segments arranged within the housing. The die segments contain a circular groove of varying radius. The die segments define an orifice having an entry plane and an exit plane. The exit plane and the entry plane are offset from the plane of rotation of the die segments. The orifice is truly round in a plane parallel to and offset from the plane of rotation. A motion control processer is interactively connected with the die stand and with the axial tension cylinder for controlling a position of the axial tension cylinder relative to a rate of reduction of the diameter of the tube.