I bought a Durst Printo table top RA-4 paper processor.
It’s a series of trays, heating elements, motors, plastic gears, rollers, and an inclined plain that spins and stirs a chemical baths. To print color photographs in a traditional darkroom
The machine takes in exposed paper and runs it through a series of baths in order to develop the image and make stable in light. They were made in the 90s before digital swallowed us whole and marketed to home darkroom color printing.
A lot of rollers and gears we're either broken, stripped or missing. The company that made these no longer sells parts and they are expensive if you find old stock online. I measured the old crumbing gears and modeled them in C4D.
It took a few iterations as I had to learn how to build things to hold up under load but I eventually got good models.
Here is a link to 3D file if you want to print your own. It only cost me a few dollars to get a whole handful of of these printed. I would suggest testing a few plastics to make sure they hold up to your chemistry.