I have an omega D2 variable condenser enlarger. It came with a 135mm rodenstock omegaron mounted on a "protruding" board of some sort. How would I mount the 50mm nikkor on it? Can I make a board myself? Is there a thread of sorts? Which parts do I need? I don't know what else to ask. I'd prefer not to buy anything else, since this darkroom project is taking a toll on my small wallet.