I build molds for a living, I went to see one of my long time customers in Kentucky last year where we went over a couple of tool designs and how they wanted to run them.
While he was giving me the nickle tour of the facility there was an OD grinder set off to the side, it was roped off with the type of velvet that they use at movie theaters and other public events. I asked what that was set aside for and he told me the story of that machine. It was the grinder that ground the O-rings for the Challenger and all the other space shuttle booster seals. When the Challenger exploded just 2 days later his shop was flooded with Morton Thiokol engineers and lawyers, Parker seals engineers, and NASA investigators.
They pretty much crawled up their butts with a spotlight trying to find any chance at all that they cut corners, used rubber extrusions other than what Parker Seals supplied, ground them out of tolerance, forgot to cross their Ts and dot their Is, He told me that it was a sh*t show of lawyers and ass coverers trying desperately to find any scapegoat they could to pin the blame on. They set the machine aside after they escorted them out of the facility disappointed they couldn’t find any reason to blame them. He credits the wife of the owner who was an old school complete perfectionist for having every base covered, had a single corner been cut on paperwork, proof of supply chain protocols, or any of about 100 different tracability issues for allowing them to withstand the whirlwind of blame they were looking to place on anyone else but themselves.
This is the "real NASA"!
Technically, centerless grinders are “OD grinders” as well, but they are two very different machines. They’re designed for grinding metal, someone who knows what they’re doing can grind more exotic materials as well. They have to have the right skill sets and even possibly different types of grinding wheels as well.
I’m just curious. I’ve never heard of anyone grinding rubber before. I don’t doubt that it can be done.