Shown is the inside of a Unicum iris. The shutter was all right on this lens, not so on another one like it that is on a 4x5 camera. I had a go at fixing it. I was successful so tried to fix this one. It is larger and was on a junker 5x7. The shutter was bad AND so was the iris. Note the holes where pins are to go. Some were missing. I replaced two using thin slices of lead pencil graphite. They won't last long but the concept was proven. I - you - can do this work. There is a thread about it on LFphotography under lenses.
A 4x5 was needed to start making small plates with; the shutter was bad, It was easy enough for me to fix and you can do it, too. Fixing the iris pins is another matter entirely.