I already had a nice laser drilled pinhole from Skink.
So on thinking which Argus to use, I looked at my Argus A2B. The lens assembly on this is a nice self contained capsule that just screws out.
The pinhole fit in easily and loosely. There was a retaining ring that came with the pinhole to hold it into the Copal 0 opening for my Graflex. That retaining ring was just a little smaller than the threads for the Argus A2B lens capsule, so I put a few pieces of blue masking tape around the threads of the camera, and then pushed the retaining ring in where it fit snug enough.
The one thing that still wasn't right was the pinhole was sliding around slightly, so I added a couple of thin strips of scotch tape to hold it centered (not pictured).
Then I set the aperture at the maximum width, set it to bulb for the long exposures needed when your aperture is f/256 and took some indoor and outdoor pictures. The outdoor ones were from one to four second exposures on T-Max 100 film and the indoor ones around a minute. They came out slightly overexposed so I adjusted it in Lightroom.
The results did not give me as sharp of a focus as I'd like and gave a heavy vignette. At first I thought the poor results were because the focal length was at 50mm rather than the 90mm the pinhole was designed for. I opened it up again to measure the actual focal length and then realized that there was a rear element lens that I had not removed which was causing the problems. Lesson learned - don't do your project the night before Pinhole day in a poorly lit room where you can't see the rear lens element.
I tried to take a spanner to the rear element, but the retaining ring is just too tight. Chalk this one up as a good idea that produced interesting, if somewhat disappointing results. I got some better pictures on my Graflex Century Graphic and will try to find time to post those as well as how I made the pinhole lens for that.
For my 2017 Pinhole Day experiments, see the post here.