This is my attempt at a worm gear for the autofocus mechanism of a Kodak 850 slide projector. The slide advance mechanism broke (because it's 40yr old plastic) and there are two gears for the autofocus mechanism that are made of the same plastic. As long as you're inside, you might as well replace them all. I bought a kit of parts for not-very-much-money from KodakParts dot com and I would actually recommend you do the same.

I was able to find two of the other parts from other makers, so I didn't attempt to create models for those, but they are

• https://www.thingiverse.com/thing:5429406 focus gear that is supposed to mesh with this worm gear.
• https://www.thingiverse.com/thing:4747708 this is the advancer bit that goes on the end of the solenoid arm

NOTE: this is untested - I have better parts from a reputable manufacturer and I'm not going to attempt this with my father-in-law's projector more than once, so your mileage may vary.

The fusion 360 model should be correct actual measurements, but were a little undersized when I printed in PETG. I scaled the X and Y dimensions to 105% to adjust. The shaft hole still measures a little undersized, but I don't have a shaft to test in on.

I printed this very fine and slow to get accuracy. It meshes almost perfectly with the purchased gear.

Included a binary and ascii STL just because, but they're identical settings