12T Pinion Gear Insert

You know that insert that comes with the metal 12T pinion gear that is the adapter for 1/4" shaft to .125" shaft? (12T Pinion Gear Insert) I’d like to buy that as a standalone part in packs of (12).

Right now that isn’t available apart from purchasing the 12T pinion, correct?


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Correct… not available separately.

You get a set of inserts with any HS gear order, not just pinions. I agree they would be nice as a separate item… as would pillow blocks, ratchets and some others.

Square inserts for the general HS gears are not compatible with the 12 tooth pinion. So once they are lost, you can’t replace it.

That seems a bit odd to me, but I can attest. I had to use the 12t inserts instead of square hub inserts on a couple of occasions (mostly laziness), and that works. Just not the other way around.

The teams started using the 12T Pinion Gear Insert in a lot of applications. One of the most popular uses was as adapters for omni wheel inserts for .125 axles. Others were using them in V5 motors so the interface for a .125 axle is longer inside the V5 motor.

The square inserts are compatible with the pinions if you have a hammer and strong willpower.


So I can’t seem to find it, but there was a photo a couple of years ago of someone trying that, I thought it was @kypyro, and it broke the pinion in half. So I have never wanted to try hammering them in myself.

Edit: Found it. Metal pinion issue