Here is an STL file of a super-8 cartridge opener that L’Abominable has designed for 3D printing, after an original device that was in service at Kodak labs back in the days.
It makes opening a S8 cartridge in the dark instantaneous and straigthforward. The end with cutter blades, saws etc.
Enjoy. We had it printed by scultpteo.com , using Nylon 3200 glass-filled printing material, which is more solid that regular PA12 nylon and we advise that you use such a material if you have one printed. It cost us 76 euros including shipping.
Then a few screws to the side of a table in the darkroom, and there you go! First, the two corners of the cartridge, and then the side. You insert the border of the cartridge in the horizontal slit, and then push it down to break.
Ah … one last thing : because 3D printing objects can have slightly different dimensions from one to the other, you might have to sand the sides where the cartridge goes for the final step, in case it sticks a little bit. It wasn’t the case for our unit, but it can happen.