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[–] 1 point 2 years ago (1 child)

using a ruler to measure a length of 1/8" is as accurate as using a ruler to measure a length of 31mm and eyeballing 2/3 of a mm

the bottleneck at that point is your eyeball and pencil lead, not the unit of measurement

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  • [–] 1 point 2 years ago (1 child)

    well, it's 3.16 mm, not 31.6, but i get your meaning.

    in that case if you wanted to be real precise, you'd measure from the left or right side of one graduation to the same side of the next graduation. using that technique a person could get a better 1/8" off a ruler than someone eyeballing fractional mms would.

    I still don't see how a calculator helps though.

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  • [–] 1 point 2 years ago (1 child)

    well yeah, because 1/8" is 3.175mm

    1/3 of a mm is a distance between 1/64" and 1/128"

    mechanical pencil lead is only about 0.4mm

    I still don’t see how a calculator helps though.

    don't ask me ask the person who posed the "what's a third of 9.5mm" question

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  • [–] 1 point 2 years ago (1 child)

    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.

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  • [–] 1 point 2 years ago

    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

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