As of now, I haven’t been able to find or make a free spinning shaft insert for the 12T pinion, like exist for the 36, 64, and 84 tooth varieties.
I would greatly appreciate it if there were a version of this part:
That had a circular middle instead of a square one, and it would be incredibly helpful, especially when making ratchets and other complex mechanisms.
Totally agree. However, if you’re in need of function, and not a new product, you can either shave down the corners of a green circular insert (so it fits) or drill out the hole in a metal or plastic 12-tooth gear.
I only have a few, and I’d rather not damage my parts. I see that that would work, but I’d rather have a specialized part for this specifically.
I don’t have any pics, but my club has some 12t metal pinions that don’t need inserts, it’s just the smaller axle size. Some are square holes and some are circular.
I have some of these too
All of mine are square.
They likely just had a member drill them and the club doesn’t remember. They were never sold with circular holes.
I had a free spinning 12T Pinion on my catapult ratchet in Turning Point. The way I made it was to simply take the plastic green inserts and press them into the pinion with a vise. I know you said you didn’t want to make single-use parts, but I just figured I would put this out there in case anyone wanted ideas.
Yeah, same here.
how about you buy more and THEN drill them out?
Astonishing absolutely brilliant
Never seen before
20 characters
My team did that last year, and I think another team from our school found a way to get them out
These would presumably be the same price as the square inserts, so why don’t you just buy square inserts and drill them out to get the same effect at the same price?
I agree that having them as a product would be nice but like @djavaisadog said, just drilling out the current square ones would work and can be done in the meantime while waiting for an official vex version (assuming they decide to make these)
At the top of the front of the claw, you see long, skinny spacer things, that when sawn to length and slid on a screw, make a nice insert for a metal pinion. I have not tested this extensively, only a little, but I assume you have access to a claw. Try it it out. 
Great idea, but the thing I needed this for required the insert to free spin on the shaft, and lock to the inside of the gear. I’m working on a new video, and it should make sense after I post that.
I already cannibalized the spacers from my claw for something else.