Design (for 3D printing) of an 8mm/2x8mm film tape cutter for Reflecta and similar scanners.

Hello everyone.

I once bought a Chinese 8mm film scanner (which supports both normal 8 and super 8 format). While there are no particular problems with super 8 format when scanning, it is worse with normal 8mm. The situation is that 8mm film stock often came in 2x8mm format (this was standard 16mm film stock with twice the perforation). The camera for the 2x8mm format would advance one half of the tape, after which the tape would be removed, put on the other way and the other half of the film would be shot. Once the entire tape had been exposed, the film was developed in a photographic workshop and cut lengthwise into two halves to obtain two 8mm films.

And this is where the problem with scanning comes in. If the film has been cut inaccurately, one half is wider and the other 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 reasonably well, the wider half does not want to pass through the film path in the scanner. As far as I have found out, this is a common problem with the popular Reflect scanner and its clones and so far there has been no good solution for this.

Looking for a solution I started a thread on Elektroda ( Link ). I tried to "sculpt" something myself that would allow me to taper the film too wide. But the results were poor. Yes, it was possible to taper, but the edge was jagged, the blade went too deep and spoiled the film. However, I finally bought myself a 3D printer to play with and decided to try making something on it, while learning FreeCAD. And this time the result was satisfactory.

I posted pictures of my contraption in that thread, so I won't repeat them here. I'll just post the stl files with the components of my film cutter. I'll also post a video showing how to insert film into this device and how it roughly works:

To make the device you need one standard razor blade (I used an "ISANA MEN" razor blade bought from Rossman and matched the dimensions of the razor blade to it, but I think this is standard and other razor blades will also fit). Apart from the razor blade, everything else is prints. The whole thing fits quite tightly and you can put it together by pressing it together, no glue needed.

My printer is a Creality K1C with a 0.4mm nozzle. Material - PLA+ by Jayo and PLA by Sunlu.

One more note about printing: The main pinwheel (file CutterDoFilmsPinwheel4.stl) is intended to be printed in the "pinwheel up" position). The slicer will probably automatically arrange it in the opposite position, but you have to rotate it for the print to come out right.

I hope that everything is clear. However, if anyone has any doubts then feel free to write - I will try to answer.