head system 12 as shown in fig1 a referring to fig2 of the drawings the first forming rolls comprise framework 114 and a spaced plate member 116 the gap between the plate 116 and the frame 114 forming a fin strip guide passageway 118 a roller member 120 is rotatably mounted at 122 and set at an angle with respect to the frame 114 for imparting a bend along one edge of the fin strip to begin formation of what will be referred to as a foot member 124 therealong the foot member 124 after passing through the first forming rolls 32 will be bent to an angle of approximately 45 u00b0 with respect to the plane of the fin strip the second forming rolls 34 comprise a frame member 126 and a spaced plate member 128 for forming a passageway 130 therethrough the forming rolls 34 comprise a roller 132 rotatably mounted at 134 and being spaced from the frame member 126 to apply a further bend to the foot member 124 to a position of approximately 60 u00b0 with respect to the fin strip referring now to fig4 and 5 of the drawings the helix nut 40 and spinal roller 42 form a wedge for allowing the fin strip 36 to be passed therebetween the helix nut 40 is provided with a central aperture 136 for receiving the central tube material 24 therethrough the rotary motion of the helix nut 40 and the cone member 42 is controlled by a synchronous control drive indicated by reference character 138 which must in turn be adjusted with respect to the knurling drive rollers 22 hereinbefore described the fin strip material 36 is passed between the spinal conical roller 42 and the helix nut.