Thanks Michael -  
That looks like a good solution for this kind of Celtic design that loops back on itself.
 
I hadn't thought of doing an extrusion and fillet.  It doesn't create that "X" pattern at the intersections that a circle profile sweep (or the actual ring) has, but this is not a detail that will get enlarged in the final render image.
 
I'll experiment with this technique and post a render.
 
Ed
   
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