"fractions of a human hair" is not something overly exciting, the average hair is around 0.05mm thick and therefore quite large. many tolerances in machining are smaller than the average hair and therefore also "fractions of a human hair" with small to medium parts. you can even machine (removal of the material by cutting, not laser or sonething else, just in case someone mistakes the type of machine) a hair on a mill, kern did that already, so it really doesn't sound too impressive the way you say it.