I just acquired a Kodak 405 mm lens but as luck would have it the iris has been removed.

I would like to make a set of stops for it, the front ring unscrews and it has that lip underneath it. My thoughts are to get the aperture sizes f/4.5 --22 -then I could just lay it in there and screw the front back on to hold it in place.

Any thoughts, or suggestions would be appreciated

Thanks John