Thank you all for the great links, and speedy replies. I got a bit lucky yesterday at a local building supply store. I was talking to a sales person and mentioned I was l having trouble finding the radius of Roman style cabinet doors. Another customer overheard me and piped up, "oh that's easy, the ends of the rail has to be 1" thicker than the top of the arch. No mater the rail length it's always 1", if the rails are 2 1/2", the ends of the rails are 3 1/2 inch". Wow, talk about being in the right place at the right time!! I learned he was a custom remodel-er and often worked with arches. I later went to the local Home Depot and measured some cabinet door on display, and they all had the 1" difference on the arches. I will figure out the radius needed for different rail lengths and make a chart. I will post my results here on the forum soon. Again thanks everyone for the great links and your input in helping me.