I have created a 3d model of a helix with very small angle.  The basic dimensions of the helix are Inner Edge 820mm diameter, Outer diameter edge 940mm , so the width is 60mm and thickness of the profile 11.6mm.  The helix in the model is shown at a pitch of 60mm and 1.5 turns making 90mm high.

I have also produced a ring wihich is at the base of the helix.  The important note here is that the upper face of the helix intersects the top of the ring. At 69.62 degrees the lower face of the helix intersects with the top face of the ring.

So in essence what Actually require is partial helix that rotates through 69.62 degrees and and the top face rises from 0mm on the top face of the ring and the final point of the top face of the helix is 11.6mm above the ring at 69.62 degrees. This is now the bit I can not work out.  The bottom face of the Helix is the same a the top face of the ring.

In effect what i need is a curved wedge, if that makes any sense. 

Hopefully one of you guys can help me with how to do, or best case complete the model.

The Model is

Helix Rev2.SLDPRT

Thanks in advance

Mike the N gauge Guy