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Re:The Dozenal Society of America by jacobolus on Sunday April 01, 2018 @10:42PM (#16731913)
Ideally this kind of thing should be roughly on a log scale, along the lines of https://en.wikipedia.org/wiki/Preferred_number, e.g. https://en.wikipedia.org/wiki/Renard_series https://en.wikipedia.org/wiki/E-series_of_preferred_numbers

You can pick a coarser or finer scale depending on the particular need.

For a base twelve world, I would recommend using binary logarithms written in base twelve (“dublogs”) whenever possible; 0.1 on such a scale matches one semitone in a 12-note-per-octave equal-tempered musical scale.

Re:The Dozenal Society of America by zokier on Monday April 02, 2018 @07:10AM (#16733622)
> Ideally this kind of thing should be roughly on a log scale, along the lines of https://en.wikipedia.org/wiki/Preferred_number, e.g. https://en.wikipedia.org/wiki/Renard_series https://en.wikipedia.org/wiki/E-series_of_preferred_numbers

Traditionally various "gauge" units have been used (e.g. AWG[1]), which are more or less logarithmic. Not quite as elegant as Renard/E series, but still craftsmen and engineers of the past were not completely oblivious of the utility of such scales.

[1] https://en.wikipedia.org/wiki/American_wire_gauge

Re:The Dozenal Society of America by zokier on Monday April 02, 2018 @07:42AM (#16733744)
> https://en.wikipedia.org/wiki/E-series_of_preferred_numbers

One interesting thing about E-series is how it includes rounding in its definition. If we take E192 as an example, naively thinking the 186th value should be 10^(185/192) = 9.19479 which rounds to 9.19. But instead it actually is 9.09*10^(1/192) = 9.19967 which rounds to 9.20 (!). I haven't been able to figure out how you would come to that figure without needing first to calculate all the preceding 185 numbers.

edit: I just noticed that the E-series tolerances do not actually match the series in the upper end; for example for 2% tolerance, E48 actually leaves gaps in the range and would be more suitable for 2.5% tolerance. For 2% tolerance hypothetical E60 series would make more sense (and kinda also mirror E6 ~ 20% series). Same applies for E96/1% and E192/0.5% where E120 and E240 (or 1.25% and 0.625%) should have been used instead respectively. I suppose it doesn't matter for practical engineering, but it does tarnish the elegance a bit.

Re:The Dozenal Society of America by eadmund on Sunday April 01, 2018 @11:40PM (#16732117)
I'm honestly not sure what you're saying, but it sounds compelling!
Re:The Dozenal Society of America by jacobolus on Monday April 02, 2018 @12:34AM (#16732367)
I'm saying that if redesigned today for our current society (either metric or imperial) sheet metal gauges should probably use something like preferred numbers for widths.

In a hypothetical base twelve world, they could instead use a log scale (think decibels) explicitly, and one nice option is to use binary logarithms, since then twelfths correspond approximately to nice duodecimal fractions. This is the basis of the Western musical scale.