Right angle 4:1 gearbox options?

We’re looking to save some room on a mechanum drive by rotating the motors 90 degrees to the wheels. AndyMark has this 2:1 right angle gearbox, but we would need something more like 4:1. This could be done by adding a 2:1 spur gear, belts, or something else. It would be easier if there was a similar gearbox with a 4:1 reduction. Any options out there?

Take a look at what Killer Bee’s did a few year ago

In 2015, 1983 Skunk Works did something similar. We used the AndyMark LJ Bevel Box and then did did a chain reduction direct to the wheels. I think we did a 4:1 chain reduction to 6" Mecanums, 16T to 48T that year.

Here’s the best picture I could find: https://photos.app.goo.gl/NoSLbktucpLuwNuD2

The only COTS bevel gear sets I know of on the market for FRC (e.g. comes in a 1/2" or 3/8" hex bore or 8mm shaft mounting) is the 2:1 pair that AndyMark sells, the 20T 1:1 sets from AndyMark, or the 15T ones from Vex.

Without a COTS 4:1 bevel set option, if you’re not interested in broaching your own bevel gear sets, you’re probably best off doing an additional reduction off of the bevel box in gears/belts/chain.

While it’s somewhat of a more expensive option you could use a4:1 CIM sportinto our new 1:1 bevel box with 57 Sport Mounting Kit (am-3840_Sport).

That’s pretty creative, I like it haha. I’m wondering how well those will hold up over a season on the drivetrain though. Being mechanum it might be okay since they won’t see a huge amount of torque (compared to say, high-traction tank drive)

Yeah, that’s pretty close to what we’re looking at! Keeping the frame open like in the photo.

Oh boy that is a pricey option…but it looks really nice too. I’ll have to consult the students and see what they’ve come up with.

Just throwing more ideas out there, has anyone used an angle grinder gearbox in their robot before?

This guy is saying the Harbor Freight 9" grinder is a ~4:1 reduction:

Attach to a VersaPlanetary 4:1, problem solved. Well, other than using a CIM or similar through a VersaPlanetary.