pic: Simple Chain-in-Tube Concept

[Aren Siekmeier]

Originally Posted by Gregor

What's the reason for the slots in the tube that mount the gearbox?

You want the gearbox position to be driven by the third bearing in the plastic housing piloting onto the shaft captured in the tube. This sets the appropriate gear spacing and prevents misalignment of any the bearings or the shaft. Then the bolts just clamp everything in place wherever it ended up.

I also really like the boxtube standoffs. I'd played around with this same idea, but still using a version of Vex's third stage plate, requiring more pieces and more disassembly to get the gearbox away from the final gear. The boxtube cleans this up a lot.