KoP TB Mini- Transmission Seizing

[Thad House]

Originally Posted by BoilerMentor

That's .025" further spaced than they should be, per a standard gear spacing calculation. I would be extremely hesitant to operate a gear box like this, because you're most certainly outside the range of appropriate gear mesh. You'll see a lot of back lash between the gears, noise, and potentially irregular gear wear or even failure.

Center distance = (N1 + N2) /2P
N1: Number of teeth on Gear 1
N2: Number of teeth on Gear 2
P: Diametral pitch

Generally we add an extra .002" spacing to account for misalignment

(13+50)/2*20 = 1.575" --> 1.577"
(14+50)/2*20 = 1.600" --> 1.602"

In our custom gearboxes, even with the extra .002", we've had situations where we see binding on one side and free movement on the other.

for reference: http://www.engineersedge.com/gear_formula.htm

The 13T pinions are really cool. They actually have a 14T center spacing, and fit a normal 14T spacing without any issues.

However, I can see an issue with using them in AM gearboxes. People have noticed in the past that AM and Vex gears do not always mesh properly. That could be one cause of your binding. If you double check the assembly, and still see the issue, try the 14T AndyMark pinions that were included with the gearboxes and see if that solves the issues.