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Customary Units and Imperial measurements are bad, we all know that. However, play Devils Advocate for a moment to see the benefits of these allegedly backwards

Customary Units and Imperial measurements are bad, we all know that. However, play Devils Advocate for a moment to see the benefits of these allegedly backwards measurements. Take the foot. This is twelve inches. You can divide a foot into thirds or sixths without any recurring numbers. This is of practical application. If you are working with some DIY task and everything is in Imperial measurements then it all works out as easy as Lego pieces.

ithkuil 6y ago
Yeah, duodecimal systems (base 12) rock! But is the customary units system consistently duodecimal? Iirc it's not, but I might misremember.
- jabl 6y ago
  No. E.g. a foot is 12 inches, but a yard is 3 feet.
  - masklinn 6y ago
    And a chain is 22 yards and a furlong is 10 chains and a mile is 8 furlong (which is why a mile is 1760 or 5280 feet.
- saalweachter 6y ago
  It's mostly binary -- 16 ounces in a pound, 16 drams in an ounce, 8 pints in a gallon, 8 furlongs in a mile, 4 rods in a chain. Then you've got a few odd ones, like 10 chains in a furlong or 22 yards in a chain or 3 feet in a yard. In general, the secret to happiness in customary units is to only ever work in a single unit and never convert between them. If you are working in construction, you probably only ever want to deal in inches. Ceilings are 96 or 120 inches tall, doors are 32 or 36 inches wide, etc etc etc. The moment you start using two units at once you are going to have a bad time, so if you pay attention people tend to only use one, even if it confuses people who don't know why doors are 80 inches high instead of 6 feet 8 inches.
- ithkuil 6y ago
  I wonder why people feel the need to downvote somebody for not being sure whether this special unit system has some feature or some other feature. I didn't say it's stupid or anything, I wasn't trolling, I just have no idea, I'm not using it. For all I know 12 feet could be some unit I never heard of. Do people really have to be fully acquainted with the US culture and/or have done full research on Wikipedia before asking a question for them to be taken seriously?
- Mountain_Skies 6y ago
  Base 12 metric should be a real thing. Maybe when we build self sustaining O'Neill cylinders we can use that opportunity to switch.
capableweb 6y ago
Thanks, this was what I was looking for. I can totally understand it's easier to cut up a plank if it's twelve inches, in thirds, using customary/imperial, as you get even numbers, compared to with metric, where you'd end up with 0.33... meters for a one meter plan. However, for a 1.2 meter plank, you'd end up with 0.4 pieces. So while I understand how it's beneficial, I don't quite understand how it's beneficial.
- bregma 6y ago
  It's beneficial in that it lets you score points in theoretical arguments on the internet. In practice it doesn't matter. For example, the floor of my bathroom is ten feet wide. I recently had to replace it, which in practice meant I had to cut a plank 9 feet 11.5 inches on one side and 10 feet 0.25 inches on the other side. It seems that the original carpenter, when dividing his plank by 3, eyeballed it it more or less so it looked right and just sort of waved their saw in the general direction of correct. It turns out that in reality, the actual arbitrary units are irrelevant. But you know, bikeshedding on which arbitrary system of units is best is a pretty effective way to procrastinate finishing off that bathroom renovation.
  - stephen_g 6y ago
    Yeah, this kind of thing annoys me to no end when I scroll through these kind of debates in comment threads. I wonder if people who pose these hypotheticals about dividing lengths down would be surprised that tradesmen and carpenters in the rest of the world get on just fine, and don’t need a maths degree to work this kind of thing out! A lot of the arguments though (and some of the most impassioned) mostly boil down to “I’m more familiar with this system so I assume it’s better” - for example, any time that people say that customary units are “more human scales” or “fractions are easier to understand than decimals” whatever. It actually makes basically no difference in practice, it’s just that growing up with one system or the other makes you a lot more familiar with it!
    - capableweb 6y ago
      > makes you a lot more familiar with it Essentially boiling down to the famous "easy vs simple" where something is "easy" if you're familiar with it and can draw conclusions via leveraging existing experience and "simple" is that it's maybe not familiar, but easier to become familiar with because it's not complex. Blatantly stolen from Rich Hickey's "Simple Made Easy" talk: https://www.infoq.com/presentations/Simple-Made-Easy/ https://www.infoq.com/presentations/Simple-Made-Easy/
SiempreViernes 6y ago
Yeah, just look at how easily these mechanics calculate a distance: https://m.youtube.com/watch?v=pikrntjcbyw https://m.youtube.com/watch?v=pikrntjcbyw
- seiferteric 6y ago
  Technically the problem here is using fractions.
Stratoscope 6y ago
Yes, twelve is a wonderful number. You can get a half, a third, a fourth, a sixth. Those are very useful. Ten only lets you get a half or a fifth. It's a much sparser set of subdivisions. The same is true if you compare a yard with a meter. There's nothing wrong with either measure, but a yard gives you a lot more factors to work with.
- jabl 6y ago
  True, but nothing prevents you from using dimensions which are a multiple of 12 in the metric system. For instance, over here the standard size for a sheet of plywood is 1200 x 2400 mm.
  - saalweachter 6y ago
    I'm pretty sure that's just a weird coincidence, with 4 feet equalling 1219 mm and rounding, like 1 rod equalling 5 meters, rather than actually aiming for 12 x 100 for divisibility.
throw0101a 6y ago
> Take the foot. This is twelve inches. I think the foot is the only unit that is useful, otherwise converting between inches/feet/yards/miles get a bit ridiculous. Also doing mathematical operations gets weird if you have to add/subtract 4' 3/4" and 2' 1/8". Surveyors, the subject of this article, actually use decimalized feet on their rods (IIRC) given the errors that inches and such can add. So while inches-feet may be useful in the wood shop, in other places it's a problem.
- c22 6y ago
  Why is this weird? 3/4 is obviously 6/8, now adding or subtracting 1/8 inch is easy. Seems easier to me than .75 - .125

ithkuil 6y ago

Yeah, duodecimal systems (base 12) rock! But is the customary units system consistently duodecimal? Iirc it's not, but I might misremember.

jabl 6y ago
No. E.g. a foot is 12 inches, but a yard is 3 feet.
- masklinn 6y ago
  And a chain is 22 yards and a furlong is 10 chains and a mile is 8 furlong (which is why a mile is 1760 or 5280 feet.
saalweachter 6y ago
It's mostly binary -- 16 ounces in a pound, 16 drams in an ounce, 8 pints in a gallon, 8 furlongs in a mile, 4 rods in a chain. Then you've got a few odd ones, like 10 chains in a furlong or 22 yards in a chain or 3 feet in a yard. In general, the secret to happiness in customary units is to only ever work in a single unit and never convert between them. If you are working in construction, you probably only ever want to deal in inches. Ceilings are 96 or 120 inches tall, doors are 32 or 36 inches wide, etc etc etc. The moment you start using two units at once you are going to have a bad time, so if you pay attention people tend to only use one, even if it confuses people who don't know why doors are 80 inches high instead of 6 feet 8 inches.
ithkuil 6y ago
I wonder why people feel the need to downvote somebody for not being sure whether this special unit system has some feature or some other feature. I didn't say it's stupid or anything, I wasn't trolling, I just have no idea, I'm not using it. For all I know 12 feet could be some unit I never heard of. Do people really have to be fully acquainted with the US culture and/or have done full research on Wikipedia before asking a question for them to be taken seriously?
Mountain_Skies 6y ago
Base 12 metric should be a real thing. Maybe when we build self sustaining O'Neill cylinders we can use that opportunity to switch.

capableweb 6y ago

Thanks, this was what I was looking for. I can totally understand it's easier to cut up a plank if it's twelve inches, in thirds, using customary/imperial, as you get even numbers, compared to with metric, where you'd end up with 0.33... meters for a one meter plan. However, for a 1.2 meter plank, you'd end up with 0.4 pieces. So while I understand how it's beneficial, I don't quite understand how it's beneficial.

bregma 6y ago
It's beneficial in that it lets you score points in theoretical arguments on the internet. In practice it doesn't matter. For example, the floor of my bathroom is ten feet wide. I recently had to replace it, which in practice meant I had to cut a plank 9 feet 11.5 inches on one side and 10 feet 0.25 inches on the other side. It seems that the original carpenter, when dividing his plank by 3, eyeballed it it more or less so it looked right and just sort of waved their saw in the general direction of correct. It turns out that in reality, the actual arbitrary units are irrelevant. But you know, bikeshedding on which arbitrary system of units is best is a pretty effective way to procrastinate finishing off that bathroom renovation.
- stephen_g 6y ago
  Yeah, this kind of thing annoys me to no end when I scroll through these kind of debates in comment threads. I wonder if people who pose these hypotheticals about dividing lengths down would be surprised that tradesmen and carpenters in the rest of the world get on just fine, and don’t need a maths degree to work this kind of thing out! A lot of the arguments though (and some of the most impassioned) mostly boil down to “I’m more familiar with this system so I assume it’s better” - for example, any time that people say that customary units are “more human scales” or “fractions are easier to understand than decimals” whatever. It actually makes basically no difference in practice, it’s just that growing up with one system or the other makes you a lot more familiar with it!
  - capableweb 6y ago
    > makes you a lot more familiar with it Essentially boiling down to the famous "easy vs simple" where something is "easy" if you're familiar with it and can draw conclusions via leveraging existing experience and "simple" is that it's maybe not familiar, but easier to become familiar with because it's not complex. Blatantly stolen from Rich Hickey's "Simple Made Easy" talk: https://www.infoq.com/presentations/Simple-Made-Easy/ https://www.infoq.com/presentations/Simple-Made-Easy/

SiempreViernes 6y ago

Yeah, just look at how easily these mechanics calculate a distance: https://m.youtube.com/watch?v=pikrntjcbyw https://m.youtube.com/watch?v=pikrntjcbyw

seiferteric 6y ago
Technically the problem here is using fractions.

Stratoscope 6y ago

Yes, twelve is a wonderful number. You can get a half, a third, a fourth, a sixth. Those are very useful. Ten only lets you get a half or a fifth. It's a much sparser set of subdivisions. The same is true if you compare a yard with a meter. There's nothing wrong with either measure, but a yard gives you a lot more factors to work with.

jabl 6y ago
True, but nothing prevents you from using dimensions which are a multiple of 12 in the metric system. For instance, over here the standard size for a sheet of plywood is 1200 x 2400 mm.
- saalweachter 6y ago
  I'm pretty sure that's just a weird coincidence, with 4 feet equalling 1219 mm and rounding, like 1 rod equalling 5 meters, rather than actually aiming for 12 x 100 for divisibility.

throw0101a 6y ago

> Take the foot. This is twelve inches. I think the foot is the only unit that is useful, otherwise converting between inches/feet/yards/miles get a bit ridiculous. Also doing mathematical operations gets weird if you have to add/subtract 4' 3/4" and 2' 1/8". Surveyors, the subject of this article, actually use decimalized feet on their rods (IIRC) given the errors that inches and such can add. So while inches-feet may be useful in the wood shop, in other places it's a problem.

c22 6y ago
Why is this weird? 3/4 is obviously 6/8, now adding or subtracting 1/8 inch is easy. Seems easier to me than .75 - .125