Yeah I just remembered about the 3/8 hole. If you can’t drill out the axle stock, you could consider 1/2" od x 0.058 wall tube like this: https://www.mcmaster.com/1968t74. Just be careful that the od tolerance might make the bearings a tight fit if you’re unlucky.
The collars didn’t work no, that’s why I recommend spacers over the tube.
Come to think about it though, someone could make a bit of money fabricating tube axles sized for the KOP chassis, including circlip grooves. Each one would probably take less than 30 seconds on a CNC lathe.
One issue our team ran into while playing some agressive defense was that one of our end plates bent inwards as a result of repeated collision, so I was wondering, has anyone experimented with reinforcement? I feel like a piece of 2x1 might work on the inside, that could be replaced with steel if a team needed the weight, but I’m not too sure. Thoughts?
Did you have an electrical board or belly pan that attached to the end plates? A stiff piece of plywood or polycarbonate that attaches to the end plates and inner rails helps to provide support to all of the sheet metal. It also keeps your rectangular robot from “parallelograming” from repeated hits. This was a recommendation in 1114’s kitbot on steroids that improves overall chassis strength.
If you had a wide robot or did not use all of the churros in the kit because of other mechanisms in the way then a strong bellypan helps even more. Wide robots have a longer unsupported end plate center that will be easier to bend through repeated hits.
I don’t remember which team, but I saw someone with a 2x4 cut down and inserted behind one of the end rails. I assume that makes it a lot stiffer. With the way the battery bracket mounts, most teams aren’t using that space between the battery and back rail for much anyway.
I haven’t seen this issue, but it seems to me that you could cut a length of the end sheet to the length between the inner sheets, invert it through rotation around its length axis, and bolt/rivet it to the end sheet on the robot, effectively making a box member, at the loss of a good bit of volume. (I am assuming, perhaps incorrectly, that the bending was in the span between the inner sheets.)