I recently purchased a Zodiac SST watch fairly inexpensively, and I have completely disassembled the movement and cleaned it and inspected all the parts and all looked good.
For some reason I didn't give the mainspring a close look and thought I should look at it again and noticed a few teeth missing on the gear. Well now that I found the problem, I'm stuck with the issue of finding a replacement.
I've searched high and low and have had no luck. Is there anyone that sources these parts? Aftermarket?

Thanks in advance,

Al-

Al,
Stripped teeth indicate serious issues in winding mechanism. If you will source a new barrel, likely it will be destroyed again.
Service is required for the movement.
No aftermarket parts for these available unfortunately.

I've cleaned and inspected all the parts and nothing looks slightly damaged. The center wheel pinion is perfect.  Crown and ratchet wheels are good. All keyless works parts are good. It's actually kind of odd considering that the winding force is at the barrel arbor and the energy is transferred to the center wheel pinion and so on. I have a  couple of working SST movements, and I'll just borrow a barrel from. I'll reassemble and give it a gentle test. It takes a great amount of force to break those teeth off the main wheel. I'm thinking this was taken out and an attempt was made to open the sealed barrel. Only hope I can find a barrel for this. It's a shame that parts are getting so hard to find for these. I love these movements.

Any help locating a barrel would be greatly appreciated.

Thanks,

Al-

I think your best option is to find a donor movement.
You need any 78, 88 or 86 caliber.
Barrel is marked "36". It means high beat version:
(https://www.vintagezodiacs.com/zforums/index.php?action=dlattach;topic=2134.0;attach=4037;image)

Buying donor for a part is always gamble. Especially 36 mainspring barrel. Due to higher tension, these barrel often show excessive wear, damaged teeth, and broken spring inside.
Good luck!