pic: Modular Gearbox

[Chris is me]

Originally Posted by Ari423

I can't find the StackerBox on AndyMark's website, but from what I can tell they seem like similar ideas (great minds think alike!). Any idea why the Stackbox wasn't successful and was discontinued? My idea was to have something similar to a VersaPlanetary in its versatility except a spur gearbox not planetary, so it can be used in higher torque situations like a drivetrain or a heavy arm. Also spur gearboxes allow you to make smaller changes in gear reducation than planetaries, which can be useful to maximize the mechanism's efficiency.

The bearing holes, aka the two in the center where the axles go in the example, are 1.125" for exactly that reason (well 1.123" for a tight fit but yeah). All of the 3/4" holes are just lightening holes because the full aluminum tube was unnecessarily heavy IMO. I suppose you could put a bearing in them for some reason or other, but that's not their intended purpose. The only holes that are intended to have bearings in them are the two 1.125" holes in the center (or the four 1.125" holes in the double block).

I just misjudged the scale of the render and thought the bearing holes were 7/8, my bad.

I can only speculate on what happened with the StackerBox (I never bought one), but I suspect the main problem was that it had limited use cases. If you wanted 2 stages, you'd just get a ToughBox; if you wanted more than that, you could get an AM or GEM Planetary. There was also less variety in gear sizes then so it doesn't have as many possible ratios as the 84T Vex spacing allows.

Any way you could move to maybe 3/4" wide tube instead of 1" tube? At the moment its not very compact, and this would thin things out a bit.