Why would I be kidding? The 2 lenses are of the same diameter. Lay the doublet down flat, presuming the back lens is either flat or concave, and then block it on 4 sides. If the back lens is convex, I have an obvious problem. I haven't disassembled the lenses yet to see. Might have to make another plan. But that plan isn't going to include spending money I don't have. I always find a way.