A device for narrowing too wide 8mm films (2x8mm)

Hello everyone.

A while ago I bought a Chinese scanner for 8mm films (supporting both normal 8 and super 8 formats). While there are no particular problems with scanning the super 8 format, it is worse with regular 8mm. The situation is that 8mm film tape often came in 2x8mm format (this was a standard 16mm film tape with twice as dense perforation). A 2x8mm camera exposed one half of the tape forward, then the tape was removed, inserted in the other direction and the other half of the film was exposed. After exposing the entire tape, the film was developed at a photo studio and cut lengthwise into two halves, obtaining two 8mm films.

And here is where the problem with scanning appears. If the film was not cut precisely, one half is wider and the other is narrower. For a standard projector, this is not a problem. But for a Chinese scanner, it is. While the narrower half of the film can be scanned fairly well, the wider half does not pass through the film guide in the scanner. As far as I can tell, this is a common problem with the popular Reflecta scanner and its clones, and so far there has been no good solution to this problem.

I have not found a ready-made good solution to this problem. However, I tried to design and make a device myself that would allow me to narrow the too-wide normal 8mm film. The device works, I published its design on the Polish website elektroda.pl. However, I am posting it again here to share the project on a more international forum.

Here is a link to the original project on the elektroda.pl website: https://www.elektroda.pl/rtvforum/topic4124163.html
Here is a link to a video showing how it works: https://filmy.elektroda.pl/16_1748554171.mp4