well, if youre’ drilling holes, 32s are pretty common, as are 64ths. my copy of machinery’s handbook uses mils, which are thousandths of an inch just like you said.

if no one makes their own rulers except labs and ruler factories then why is making rulers important for portability, something your said was important?

metric doesn’t have any more precision because of it’s definition based on a universal constant. over time as new constants arose, plenty of non metric systems adapted to them and changed to include their enhanced precision. the nautical mile is a great example of this! metric systems have also switched universal constants over time to become more and more precise, just like everything else.

a measuring system needs easy conversions most when the people using it can’t just look at the thing being measured and say “that’s not five hogsheads you imbecile! that’s a tun!” metric’s easy conversions are really good for stuff like voltage and the distance from the earth to the moon, but should everything be powers of ten? i don’t know. it certainly would remove pressure from people to learn how to easily divide by other numbers or comprehend fractions.

i’m not sure that’s a good thing.