An apparatus for the cold forming of longitudinal ribs and grooves in lengths of thin wall metal tubing, particularly cylindrical tubing, including a base support (2) mounting a tube end support (6) and an aligned roll-former assembly (4), and thrust means such as hydraulic ram thrust means (1) for moving either the tube end support (6) or roll-former assembly (4) towards and away from the other. The roll-former assembly (4) includes a planar support (7) with a central opening (8) about which a plurality of roll or wheel formers (11) are mounted in spaced relationship for rotation in substantially radial planes extending longitudinally of ,the apparatus; the inner peripheral parts of the roll or wheel formers being shaped and spaced, according to the desired form and depth of the ribs.and grooves to be formed in a tube length (5). The tube length (5) being mounted with one end of the tube end support (6) and the other end part co-axially located between the roll or wheel former inner peripheral parts, and forced longitudinally therebetween by the thrust means (1) in longitudinally cold forming the ribs (5b) and grooves (5a) from outside the tube length and without any inner co-operating mandrel or roller(s). For cylindrical tube lengths, partially axial rotation of the mounted tube length or the roll-former assembly (4) as the thrust means (1) is operated, will form at least partially helical longitudinal ribs (5b) and grooves (5a).