I had a summer job one year working on space stuff. I was in the clean room and the first day they took me back there, white suit and all, and took some ball b

I had a summer job one year working on space stuff. I was in the clean room and the first day they took me back there, white suit and all, and took some ball bearings off a wire rack. They were maybe a foot in diameter. My job that summer was to test to see which were the least noisy. (Basically, they rotated very slowly, and there was a phono needle resting on the outside with a strip chart measuring the vibration caused when balls hit each other, etc.) The best ones were going up. They told me to be careful. These were the rejects from another project, but this project was legally required to use only US tech and the US no longer had the ability to manufacture bearings this large, since we had outsourced for some time and everyone who could do it got out of the business. So we needed these exact ones. (This was the late 70's.)