Egg Timer Wind-up Gear Replacement

One of the gears on our mechanical egg-shaped kitchen timer broke - the one that connects the mechanism to the enclosure, so of course I made a replacement. I know, the whole timer thing costs only a few bucks, and it would have been easier to just buy a new one instead of messing about with calipers and tiny involute gears (by the way, the gear has 21 teeth and its module is 0.6mm with pressure angle of 20deg - if you plug those into FreeCAD's InvoluteGear wizard, the exactly right shape comes out, lucky me) - but we both know that once you own a 3D printer, it's no longer about "simple" or "easy" or even "reasonable" sometimes. Every broken thing in your house is now a challenge, a call to action, an inspiration, an excuse to put on noise-cancelling headphones and disappear into the world of sketches, extrusions and constraints...

The hammer is poised, and the nails are waiting. Don't stop now!