Abstract: A supply of elongated metal tubes are successively transferred laterally to and from a reducing position aligned with the axis of a hollow spindle, and one end of each tube is clamped by a gripper mechanism mounted on a carriage supported between two vertically spaced horizontal lead screws. Each tube is fed by the carriage onto a non-rotatable mandrel located within a non-rotatable guide tube supported within the spindle. The mandrel is supported by a mandrel rod and a centering cone movable axially on the rod within the guide tube, and the mandrel is positioned within a zone where a set of shear forming wheels are orbited around the metal tube by an annular forming head supported by the spindle. While the head is rotating, the orbiting forming wheels are movable radially in response to movement of an eccentric cam mechanism operated by an actuating tube carried within the spindle.