Abstract: A straight axial length of round metal tube is deformed such that the tube cross-section is D-shaped and coiled into a helix, a coil mandrel and wheel mandrel simultaneously drawing and deforming the tube cross-section without kinking. The interiorly facing flat faces of the helix define a substantially continuous cylindrical surface which allows the helix to be rapidly mountable onto a cylindrical heat transfer evaporator tank of a flaker ice making assembly. To provide enhanced heat transfer capabilities the helix could be undersized to tightly grip the evaporator tank and the tube convolutions could be brazed or soldered either together or adjacent the corner portions and tank.