even if you’re in a situation where it’s somehow possible to manually draw 1/3 of a mm to any accuracy, 1/3 scale draft rulers still exist for metric, so it’s equivalent
I seem to remember you as the one who brought up calculators
because as soon as you have access to a calculator, “off the top of your head” is an irrelevance
Usually when I’m making a precise line, I’ll put an edge on the pencil lead so it will make a mark thinner than its diameter.
I seem to remember you as the one who brought up calculators, but I’m open to being mistaken.
even if you’re in a situation where it’s somehow possible to manually draw 1/3 of a mm to any accuracy, 1/3 scale draft rulers still exist for metric, so it’s equivalent
because as soon as you have access to a calculator, “off the top of your head” is an irrelevance