[Jared]

This is a really cool idea and a neat design. I have a few comments/suggestions to make it stronger.

Originally Posted by asid61

I know about the 3/16" thickness. I'm changing it to 1/4", and I'm adding a couple spacers from McMaster for strength.

If you put some type of brace like 1640 does so that the module has 4 sides, it would likely get a lot stronger. I can't see if you've done this already, but if you have a lower dead axle that is a 3/8" bolt and you put spacers on it, you'll add a ton of stiffness to the rotating piece.

The wave washer diesn't actually take much load at all. Bevel gears are inclined to turn away from the axis of the mating bevel gear, so the wave washer just spaces it away when not driving.

I think you'll probably be okay here, especially if the distance the gear can move too close is small.

When driving, the bevel gear is forced against the inner race of the hex bearing.
Vex bevel gears have a small diameter boss on the back end which sit inside the diameter of the inner bearing race on the 3/8" hex bearings. If that actually becomes a conern, then it's easy to just add a thrust washer there. Can somebody explain why having the bevel gear boss on the bearing inner race won't work?

We've run a setup with a worm gear driven by three CIMs which had no thrust washer and saw no wear on the bearing or the worm. However, some teams here who have run a swerve (IIRC it was 2517?) have commented that they saw issue due to thrust loading a bearing. I would ask other teams and see if they got away with this.

What do you suggest for the lower bearing? Keeping in mind that these are 3/8" hex bearings with a relatively large inner race, I'm not sure it will be a problem.

The two bearings in the what looks like a 1 x 2 aluminum box will hold the 3/8" drive shaft pretty rigidly. The first concern is that there are only three total bearings. Whenever you push on the side of the rotating piece, you're loading the lowest hex bearing in the module. Bearings are really bad at these torques. It's like doing a West Coast drive style bearing block, but with only one bearing. Adding that second bearing changes it from trying to bend the shaft to the side, to an axial load, that the bearing can handle much better.

All that said, I would look into using a different type of bearing/bushing. All swerves that I've ever seen that are set up like this have two bearings/bushings that go on some round stock that sits on top of the rotating piece. Usually, these bearings are either huge (1" ID or so) ball bearings, IGUS bushings (see 1640's swerve), Silverthin bearings (>1" ID, see 118's old swerve), or some custom bushing (see revolution swerve from 221 robot systems).

The strength of this bearing should also be determined by what the field looks like. If there's a bump/step like in 2012, 2010, or 2004, or if there's something you can bump the wheel into, like the corner of the pyramid, you may want something very strong. If it's an open field, this may be less of a concern.

Also, I'd recommend going to a larger OD thrust washer, or just using a thrust bearing.

I did not consider chain speed. Thank you for pointing that out. Belts could actually be used in this application, so I'll switch to those. Alternatively, a cimple box or a vex 1-stage gearbox could do it too.

Most of these issues can be solved just by switching to non-coaxial.

We've run chain this fast in a shooter prototype. It's scary, but not impossible.

This is an awesome design, and it's surprisingly light compared to some more complicated swerves.