Cutting and perforating my own 9.5mm film using 16mm stock

For many years I've dreamed of being able to make my own 9.5mm film, as it's no longer produced anywhere in the world.  Als many years ago I bought a DIY hand crank music box. They come with a tiny punch which makes holes in the paper strips so you can make your own tune;

The punch cuts lovely holes in film:

But this makes round holes whereas 9.5mm film needs a rectangular sprocket hole of a very specific size and shape.

Or does it??
The punch is roughly the right width so maybe it would work, and it costs nothing to find out. I cut down some old strips of 16mm double perf, just roughly measured by eye:

then punched holes in the film, again just measuring roughly using the lines on the pad as a guide:

The punch did the job and the result looked lovely:

But could it possibly work in a camera?

I tried it in 3 different models, a c1923 hand cranked Pathe Baby, a c1933 motor driven Cine Nizo Model F, and a 1959 Prince. It worked perfectly in all three! And it also worked with the single shot function in the Prince.

I'm hoping the claw is catching the film consistently in the same place between the sprocket hole each time, and that it's roughly central to the hole so the frame isn't shifted up or down. Maybe this wouldn't work in a projector, but at the moment I just want to be able to use these wonderful old cameras with colour film, and I can telecine the results.

The next job is to automate the process a little more; at one punch every 5 seconds, I won't be going into commercial production any time soon...

Here's the video showing the 3 cameras, 2 clips repeated for clarity, and the single shot function at the end. Exciting times!