🚀 go-pugleaf

In article <1i9j4gEINN8nd@uni-erlangen.de> mskuhn@immd4.informatik.uni-erlangen.de writes:
>Here for the aprox. 5% of the world population that don't use ISO paper sizes
>the dimensions of 3 of the most popular sizes:
>
>    A4    210 x 297 mm
>    C5    162 x 229 mm (envelope for A4 folded to A6 format)
>    DL    110 x 220 mm (envelope for A4 folded twice parallel)
>
>1 inch is 25.4000000 mm.

1 SI inch is 2.54mm _exactly_, not just to 7 decimal places.
But the people who don't use ISO paper sizes don't use SI inches
either, they use NIST inches, which differ from SI inches well before
the 8th decimal place.  (I don't know the exact details - after all,
why should I know about American internal standards?)

I believe NIST inches are a standard unit in HyTime.

Does the persistence of the NIST inch have anything to do with the
US public's huge stock of old guns needing new ammo machined to low
tolerances?  Britain had no problems redefining its Imperial measures
as SI multiples...  I wonder.