[mathking]

The piece of tubing in question had been repositioned a number of times as we tested the conveyor system to find the best place to position a cross member. The holes were already drilled for mounting, and we needed to move it around to find out where performance was the best, so we weren't going to use rivets. The whole assembly is designed to be (relatively) easily and quickly removed from the robot in case we need to repair it or get access to other stuff.

It was done by hand, using a nut driver and a wrench. And by one of our most careful and sharp students. She was just paying attention to the other side (which had very little free space and needed to be fairly precisely positioned) and over tightened the bolt.

But I must say I like a student (or anyone) who owns up to a mistake and uses it to teach others not to repeat the mistake. So she earned a little more respect from me over this.