These gears are for Matthias Wandel's box joint jig (woodgears.ca/box_joint/jig.html) as an alternative to cutting gears out of plywood.

12 and 16 tooth gears go on the active shaft of the jig. I added a drop of super glue between them and drilled 3 small holes for the prong T-nut to lock into the 16 tooth gear.

32 tooth gear goes with a handle on the top plane of the jig at 90 degrees to the 12/16 pair. Handle is held together with a M5 bolt and nut. You should either use a nylon nut or after assembly put a drop of super glue on the nut to prevent it from detaching from the bolt. The handle should spin freely about the gear without coming undone (make sure hole is slightly wider than the bolt threads). I used pliers to slide the bolt through the gear and handle a few times, which makes it act like a file.

3D printing advantage is getting the teeth more accurately positioned and spaced.

Future Work
For larger gears I was thinking of printing them in 4 quadrants with a joint that can be glued together easily. Let me know if you're interested in a larger gear in the comments section.

--
Tip me for a coffee here https://paypal.me/akennberg