Abstract: An integral outwardly extending transverse annular flange is formed on one or both extremities of a previously formed cylinder, circumferentially spaced circular openings are then punched in the one or both flanges. An adjustable expansible and freely rotary mandrel, adapted to grasp tightly the internal wall of the cylinder, is mounted adjacent to one end of a movable support which is pivotally mounted and movable relative to the base from a horizontal to a vertical position. A pair of cylindrical forming or tooling rolls on parallel vertical axes are mounted on the base. The axes of the inner roll, adjacent to the pivotal joint is fixed, while the axis of the outer roll is movable and operable under high pressure to clamp a small portion of the periphery of the lower extremity of the cylinder between the rolls, corresponding to the width of the flange.