Wait until you learn about shrink rules, used in patternmaking!
Cast metal shrinks when it cools and solidifies. To make patternmaking tolerable, shrink rules are scaled up by the shrinkage allowance so that 5" in the pattern doesn't have to be scaled by the patternmaker to some random measurement. Unfortunately, the shrink allowance varies among metals...
A steel framing square also has some completely cursed scales. I'm not a carpenter, and I won't even pretend to know why anyone needs inches graduated into 10ths or 12ths.
Cast metal shrinks when it cools and solidifies. To make patternmaking tolerable, shrink rules are scaled up by the shrinkage allowance so that 5" in the pattern doesn't have to be scaled by the patternmaker to some random measurement. Unfortunately, the shrink allowance varies among metals...
A steel framing square also has some completely cursed scales. I'm not a carpenter, and I won't even pretend to know why anyone needs inches graduated into 10ths or 12ths.