Abstract: An apparatus for forming helically wrapped spine fin heat exchanger tubes is disclosed which includes a rotatable cutter head operable to cut a strip of thin metal to provide a base portion and a multiplicity of spines integrally joined at one end to the base portion. A tube feed is provided to axially feed smooth tubing past the cutter head. As the tube is fed past the cutter head the cutter head operates to helically wind the spine fin material on the tube. A first drive is provided to drive the tube feed and cutter head in time relation to ensure that the tube is fed through a predetermined minimum distance during each revolution of the cutter head. A second drive is provided to increase the distance through which the tube is fed during each revolution of the cutter head to increase the helix angle of the material being wound onto the tube and correspondingly reduce the spine fin density at selected locations along the tube.