pic: FRC3928 2013 Butterfly Module

Since this got referenced and there wasn’t a legitimate picture of it on CD…

what kind of hub did you use for the traction wheel?

Since your cylinder mount doesn’t pivot, could you go into some detail about how you attach the cylinder to the module?

It just pushes on a standoff. There is some sideways sliding contact but it’s a non-issue.

If you’re having trouble visualizing, you can check out this video of 3847’s modules from 2014:


Ah, that does seem like the simplest solution. Thanks!

In this instance the traction wheel was made from a solid piece of 2.5" diameter Delrin, the Pulley was milled into the side, and two 3/8" bearings were pressed into it.
Had access to a CNC mill, decided to minimize the part count and not require ordering a pulley.


And now I know where Adam got his 2013 offseason drivetrain design.

What would someone look for if they were trying to find an extrusion like you guys used for the main structure of these rails? As well, how are you planning to connect the frame up once both side rails are completed? The pattern of those holes looks like it would be great for designing attachment points.

As this was our 2013 robot, you can see how the frame was designed to be assembled here.

Also for reference this is 3"x3" x .125" wall Aluminum tubing, nothing special.
Online metals has it but a local supplier will give a better price.