While whipping out a couple of these http://oldradio.ca:83/Photo/Construction/LensBoards/Agfa8x10.jpg (photo available daytime eastern only) I had an idea about lens mounting. Every wooden lensboard that I've seen which mounts a lens with a retaining ring rather than a flange, uses a thin layer of the wood for a sandwich between lens and ring. Would a bit of 1/8" aluminum plate screwnailed to the front of the lens board not work just as well and sandwich the aluminum between lens and ring? Instead of having to cut a stepped hole in the board, just cut a hole in the board larger than you need by about an inch and mount the lens on the aluminum plate? - Sorry no picture of plate.