My daughter is a professional photographer working for a large commercial corporation. Some of the studio cameras use lenses that mount on a lens board as you see here. That is not a real piece of board, but rather a cast aluminum plate. I think the idea is to make lens changes and adjustments easier.
On this one someone bought the lens board with a hole that was too small. Maybe they got a deal? You can always make a hole bigger right? Problem is most people do not know how to make the hole bigger. If they know, they probably don’t have the proper tool.
I was given another lens board with the hole being much larger than necessary. “Just make the small hole half way bigger than the large hole.” I was told. I love those accurate working dimensions. Ha!
It was dang close to being a 2 inch hole I suspected I needed. I bored the small one out to about 1.995 inches. I was actually thinking 2 inch but short is better than taking too much.
My daughter took the lens board to work and sure enough the hole was still too small. “It needs just a hair more, Dad!” was her request. Uh… “What color hair, kinky, curly or straight?” I went for red, curly.
In the pix I went out to 2.010, so I’ll see if I got the color right…