VEX Robotics 3" and 4" Wheel Hub Inserts

The square and round wheel hub inserts for the VEX wheels don't stay in place, so these replace them. I put a few drops of super glue on them, insert them into the hole, and pound it in with a hammer.

The hole for the shaft sometimes prints tight or has tiny filament blobs on the inside. To clean it out I came up with a great trick. I take a 4" shaft and pound one end with a hammer on a hard surface. This puts little burrs on the end of the shaft.

I put a drop or two of super glue in the hole on the wheel. Then I put the hub into the hole on the wheel and tap it down. to avoid crushing the lip around the hole on the wheel, I put the head of a large nail on the hub and pounded the sharp end, or a 1/4"-ish bolt, to push the hub in the final 1/8" Finally, I slid the wheel halfway off my desk so the hole was over open space. Alternately, you could lay the wheel over a vise that is open 1/2" to give the shaft somewhere to go when it comes through. I put the shaft with the burrs on top of the hub and start pounding. The burrs clean out the hole so a shaft slides through pretty easily. If a shaft was still tight and hard to push through, I would flip the wheel and tap the burr shaft through the opposite way to clean out the hole a little more. That was usually enough to allow the wheel to slide onto the shaft easily.