[–] 3 points 3 years ago (3 children)

sure you can, you say “i need a hole with diameter 0.25” +- 0.015625“”. it doesn’t matter that you have more sig figs when you state your precision

but regardless, that’s probably not the precision you care about. there’s a good chance that you actually want something totally different, like 0.25+-0.1”. with decimal, it’s exceptionally clear what that means, even for complicated/very small decimals. doing the same thing fractionally has to be written as 1/4+-1/10”, meaning you have to figure out what that range of values are (7/20” to 3/20”)

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  • [–] 9 points 3 years ago (5 children)

    i’ve never heard of anyone using non-reduced fractions to measure precision. if you go into a machine shop and ask for a part to be milled to 16/64”, they will ask you what precision you need, they would never assume that means 16/64”+-1/128”.

    if you need custom precision in any case, you can always specify that by hand, fractional or decimal.

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