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Dimensional lumber tape measure
(slrpnk.net)
I hope it’s not against the rules here, just saw this woodworking related xkcd that I enjoyed and thought it might be appreciated here:)
It doesn't shrink by a half inch in each direction.
The board is rough sawn to 2x4, kiln dried, and then milled. That milling takes it down to 1.5x3.5 inches. Used to be, the carpenter bought rough boards and milled them himself, now they do it for you to save the weight when shipping.
Oh, also: 1 1/2 inches is 1/8th of a foot. 3/4" is 1/16th of a foot.
It's not often that I'm surprised by some of the divisors that appear in US Customary or Imperial units, but I'm now shuddering to imagine what sort of horrific system of unit names have been built atop this fact of twos-powers fractions of a foot.
Knowing the English, they'll likely have invented a name during the medieval time for 1/8th of a foot (1.5 inches), like dozebarleycorn, since a barleycorn is already 1/3 of an inch. And then 3/4" might be a demidoze, or some such insanity. The horror, the horror.
Or they'd pull a Worcestershire and pronounce "Inch and a half" as a "chunnauff." Gotta get that unnecessary U in there somewheure.
2 weeks is a fortnight, so is 2 feet a fortinch?
I'm informed the British do read the time 6:30 as "half six", a shortened form of "half past six". So "inch an a half" might become "incuax", pronounced as "in-cha" and containing the unnecessary U, and an X for that Norman/French faux lineage.
Naturally, Americans would instead pronounce it as "in-coh", which would destroy any understanding when also speaking about Incoterms.