Zenith fine tuning gear

[RetroHacker]

I'm seeing this in just about every 60's era Zenith I work on as of late - the little white plastic gear in the tuner for the fine tuning is split and loose on the shaft - or occasionally in pieces, having fallen off the shaft entirely.

For reference, here's an example, from a 1965 21" B&W 60 pound metal "portable".

You can see how the plastic gear has split - the plastic is now very brittle. I have attempted to epoxy these back together with no real success, the plastic does not take to the glue very well, and it doesn't really stay stuck together. And, like the most recent one of these I worked on - sometimes the gear is broken into multiple pieces.

Now, as much as I dislike the practice of using a 3D printer to solve any and all problems, this is one of those problems that a 3D printer is about the best solution I can think of. Of course, the gear is too tiny and has too much fine detail for a common home printer, but I know that commercial machines can handle this.

Now, I'm prepared to spend the time to carefully measure one of these things with calipers and figure out the dimensions and pitch and get an STL file created for this part. But before I go reinventing the wheel, er, gear - has anyone already done this or is there an available replacement? And does anyone know how many different gears Zenith used - or was it all the same in this period? The three sets I've had apart recently all used the same one, but they were also similar mid 60's designs.

-Ian