> U.S. customary (the more accurate name for what’s sometimes the called the British Imperial system)
For those wondering why there is this distinction, the British Imperial units were created by the Weights and Measures Act 1824; US customary units follow the Winchester Standard of 1588.
The US being stuck in imperial is such a meme nowadays with "freedum units" and the like. It's yet another odd thing that makes it easy for the rest of the world to laugh at the US. In these isolationist times I doubt this will change soon though, but it'd definitely help international collaboration.
The problem is that Fahrenheit is a bit more convenient for describing the weather. Inches and feet are a bit more convenient for measuring human scale things and for being easily divisible by more numbers. And we’re used to the rest of it.
Unless someone comes along and forces it on you, for the average person, there’s not enough incentive to switch.
I'd part with cups and teaspoons/tablespoons and the like, but you'll pry inches/feet/yards and fahrenheit from my cold, dead hands. They're both more convenient for daily use. I think I'd prefer to keep miles as well but I don't have a good reason for that one.
Fahrenheit has more precision without using decimals for the thing 99% of people are using temperature measurements for: air temp. Where I live, we generally experience 5 degrees F - 100 degrees F at different points of the year. That's 95 degrees of precision with no decimal. In C, that's -15 to 37.8, a mere 52.8 degrees. The difference between 75 (usually a beautiful day) and 85 (hot) is 23.8C to 29.4C. Everything packed into this tight range.
Inches/feet being base 12 divides better into thirds and fourths, which is very useful in construction.
I've lived with deg C my whole life it is what I'm used to, the way I experience weather is in 5 degree increments - I live on East Coast of Australia. My Internal rule of thumb is:
Below 10 deg C - it is cold, Heavy jacket weather
10-15 Typical winter weather (at least where I live) light jacket
15-20 Spring/Autumn weather long sleeves no jacket required
>Fahrenheit has more precision without using decimals
Meanwhile, I'm fine at 98.6 degrees, but everyone freaks out over 100 degrees. it's a more precise unit, right?
feet/inches make more sense to be attached to. they are based on your body parts (roughly), and we spend a lot of time looking at humans. inches divide our fingers, feet are... well, feet. And yards are steps. We intuitively know what all those feel like through everyday life compared to the scientific way we derive a centimeter. inches and feet being base 12 is more a coincidence than anything else (or maybe not. Maybe there's some golden ratio shenanigans at play).
"Back when I was a Catholic-school kid in northern Wisconsin, my school lessons briefly focused on the metric system. This was in the late 1970s."
Man, the progressive school (Comanche Elementary in Overland Park, Kansas!) must have had a huge impact on my life. In addition to open classrooms (I was in Unit 5, not 4th Grade), team teaching, a focus on experimental science, a circular layout to the school with a sunken (architecturally) library in the center…
Yeah, we went over the Metric System that whole year. I can still sing the "Metric Family" song from the film on metric units ("Kilo", "Milli", etc.). And to my young and impressionable mind, the U.S. was joining the rest of the "Free World" in a kind of Star-Trek-like casting aside of the old things that divided us—joining each other with a focus on progress, science, space…
President Carter came along around the same time or shortly after. And I have a photo of a family road trip to South Dakota, Montana: the sign that indicates the altitude of a particular mountain pass has both feet and meters. I Google-mapped the same location recently and of course it's no longer in meters.
I feel like in my elementary school days (the 1970's) the U.S. was on the cusp of a future of optimism—no doubt buoyed by having put astronauts on the Moon, but I was wildly on board for it.
But then some kind of shit seemingly started to poison the country. I don't feel we have ever returned to that level of national optimism. Perhaps 1976, the Bicentennial, was the end of it. (Recently watching the film "Nashville" brought me back a bit of the vibe of the times.)
I read once that all the educational materials produced to help people move from the old system to metric would cover 3 football fields and weigh more than 28 elephants, so it's nice to see it starting to have some effect.
Hopefully some future president will mandate that the federal government use metric, like Trump getting rid of the penny. The rest of society will gradually come along.
Honestly, the best way to cook is with grams. Throw everything into the same pot on a scale and keep zeroing it out. Way less mess to clean up. All the top baking recipes tend to already be in grams, but there's plenty of others out there that are not
Also a great use for LLMs. I'll tell it to convert recipes from volume to grams by estimating density. It's surprisingly accurate
You can keep your fahrenheit, your feet and your gallons, for all I care, but one thing I will never abide is bolts and nuts and drill bits coming in fractions of an inch.
It’s a bit odd in the U.S. because we use a mix of units, largely due to industries that combine metric and imperial systems. Most people are familiar with metric volume since so many drinks are sold in 1 and 2 liter bottles, and medications are typically measured in milligrams. Lengths and weights are more of a mixed bag. Many track and field events use metric units now, though longer distances are still measured in miles. Temperatures are still Fahrenheit, which I tend to prefer because the smaller increments give a more nuanced sense of change. I’m comfortable with the metric system since I was a chemistry major in college and a mountain biker, where measurements like suspension travel are usually given in millimeters.
It will never cease to drive me batty every time I try find a metric fastener for an automotive purpose at a local hardware store.
There are many reasons I can find for leaving the US, but engaging in DIY projects utilizing local suppliers are what's come closest to pushing me over the edge. Especially in this post-SEARS hellscape of low quality made in china junk the market's flooded with. Now not only can I never find the fasteners I need, the tools suck too!
>They specify dimensions in feet, inches, and fractions of an inch. But not all of them do.
There are many more fun and exciting non-metric measurements you might encounter than plain old fractional inches.
A fabricator might encounter sheet metal thickness in "gauge". Wire sizes, ammunition, and machine screws also come in "gauge" sizes but all four are different scales. US drills come not only in fractional inch sizes, but letters and numbers as well. Furnace efficiency is often specified in percent, but air conditioner efficiency comes in SEER. Water softener capacity is in "grains". Pipe threads come in "inch sizes", but that usually means NPT.
Metal hardness and rubber durometer measurements have their own scale which doesn't really belong to either camp.
To be fair, a lot of these are categorical units. Screws come in #2 or #6 or #4, but you'll never need to worry about #3.7.
A wise professor once told me "All these different units will not be going away within your lifetime, so you better get used to working with them."
The highway between Tucson and Nogales, Arizona, I-19, is the only highway in the country that has signage only in kilometers. It has been that way since 1980. It was a pilot project for the Metric Conversion Act. The highway is 102 kilometers long (63 miles).
If you specify all your bolt heads as 19mm and 13mm, then a 3/4" wrench or a 1/2" wrench is usually good enough to get the job done.
Similarly, a 1/4-20 bolt will fit in a M6 tapped hole if you use a large enough hammer.
A hazardous aspect of US threadforms is that #10-32 machine screws and #8-32 machine screws have the same pitch. So you can fit #8 bolts in a #10 hole and sometimes, they FEEL like they made good torque, because they engaged one side of the tapped hole, when they really have no tension capability whatsoever.
Reference the British Airways flight 5390 accident where the pilot got sucked 3/4 the way out the cockpit window and slammed against the side of the fuselage while a flight attendant clung to his feet and the co-pilot safely landed.
Also note that a British designed and built product was using US threadforms...
1. "They're more intuitive". They're not. You're just familiar with what 70 F feels like. If you're used to metric, 70 F is meaningless, but you intuitively know what 20 C feels like.
2. "Metric leads to lots of awkward numbers." All systems will fortuitously have round numbers in some contexts and awkward numbers in others. Customary units are different in that there are awkward numbers baked into the system. e.g. 5280 feet in a mile. 128 ounces in a gallon.
3. "It's too much trouble to change." You're already using metric units. U.S. customary units have, metrologically, been defined in terms of metric units since the Mendenhall order of 1893[1]. i.e. A meter is defined in terms of how far light can travel in a period of time defined by a hyperfine transition frequency of Caesium. If you needed to know exactly how long a meter is for a very precise measurement, a reference meter could be produced in a lab by aliens who have no idea what a meter is by using this definition. No such definition exists for a foot or yard. Nobody maintains physical reference yards (the old-school method) anymore. If you want those aliens to measure out a yard precisely, you tell them how to measure out a meter and then tell them 1 yard = 0.9144 m.
43 comments
[ 2.6 ms ] story [ 51.5 ms ] threadFor those wondering why there is this distinction, the British Imperial units were created by the Weights and Measures Act 1824; US customary units follow the Winchester Standard of 1588.
Unless someone comes along and forces it on you, for the average person, there’s not enough incentive to switch.
https://www.youtube.com/shorts/XiEM57ifX54
Fahrenheit has more precision without using decimals for the thing 99% of people are using temperature measurements for: air temp. Where I live, we generally experience 5 degrees F - 100 degrees F at different points of the year. That's 95 degrees of precision with no decimal. In C, that's -15 to 37.8, a mere 52.8 degrees. The difference between 75 (usually a beautiful day) and 85 (hot) is 23.8C to 29.4C. Everything packed into this tight range.
Inches/feet being base 12 divides better into thirds and fourths, which is very useful in construction.
For science, sure, I'll use metric.
only because that is what you are accustomed to
because I grew up with metric, m/cm are much more convenient for daily use
I will allow that a "foot" is useful as an approximate intermediary unit between m and cm
> Inches/feet being base 12 divides better into thirds and fourths, which is very useful in construction.
again only because the US construction industry grew up using fractions instead of decimals
Below 10 deg C - it is cold, Heavy jacket weather
10-15 Typical winter weather (at least where I live) light jacket
15-20 Spring/Autumn weather long sleeves no jacket required
20-25 Pleasant day T-shirt weather
25-30 Getting hot, ceiling fans/AC time
30-35 Hot
35+ very Hot
Meanwhile, I'm fine at 98.6 degrees, but everyone freaks out over 100 degrees. it's a more precise unit, right?
feet/inches make more sense to be attached to. they are based on your body parts (roughly), and we spend a lot of time looking at humans. inches divide our fingers, feet are... well, feet. And yards are steps. We intuitively know what all those feel like through everyday life compared to the scientific way we derive a centimeter. inches and feet being base 12 is more a coincidence than anything else (or maybe not. Maybe there's some golden ratio shenanigans at play).
Man, the progressive school (Comanche Elementary in Overland Park, Kansas!) must have had a huge impact on my life. In addition to open classrooms (I was in Unit 5, not 4th Grade), team teaching, a focus on experimental science, a circular layout to the school with a sunken (architecturally) library in the center…
Yeah, we went over the Metric System that whole year. I can still sing the "Metric Family" song from the film on metric units ("Kilo", "Milli", etc.). And to my young and impressionable mind, the U.S. was joining the rest of the "Free World" in a kind of Star-Trek-like casting aside of the old things that divided us—joining each other with a focus on progress, science, space…
President Carter came along around the same time or shortly after. And I have a photo of a family road trip to South Dakota, Montana: the sign that indicates the altitude of a particular mountain pass has both feet and meters. I Google-mapped the same location recently and of course it's no longer in meters.
I feel like in my elementary school days (the 1970's) the U.S. was on the cusp of a future of optimism—no doubt buoyed by having put astronauts on the Moon, but I was wildly on board for it.
But then some kind of shit seemingly started to poison the country. I don't feel we have ever returned to that level of national optimism. Perhaps 1976, the Bicentennial, was the end of it. (Recently watching the film "Nashville" brought me back a bit of the vibe of the times.)
I've been missing it my entire life since.
https://www.nist.gov/blogs/taking-measure/pirates-caribbean-...
Also a great use for LLMs. I'll tell it to convert recipes from volume to grams by estimating density. It's surprisingly accurate
There are many reasons I can find for leaving the US, but engaging in DIY projects utilizing local suppliers are what's come closest to pushing me over the edge. Especially in this post-SEARS hellscape of low quality made in china junk the market's flooded with. Now not only can I never find the fasteners I need, the tools suck too!
There are many more fun and exciting non-metric measurements you might encounter than plain old fractional inches.
A fabricator might encounter sheet metal thickness in "gauge". Wire sizes, ammunition, and machine screws also come in "gauge" sizes but all four are different scales. US drills come not only in fractional inch sizes, but letters and numbers as well. Furnace efficiency is often specified in percent, but air conditioner efficiency comes in SEER. Water softener capacity is in "grains". Pipe threads come in "inch sizes", but that usually means NPT. Metal hardness and rubber durometer measurements have their own scale which doesn't really belong to either camp.
To be fair, a lot of these are categorical units. Screws come in #2 or #6 or #4, but you'll never need to worry about #3.7.
A wise professor once told me "All these different units will not be going away within your lifetime, so you better get used to working with them."
Similarly, a 1/4-20 bolt will fit in a M6 tapped hole if you use a large enough hammer.
A hazardous aspect of US threadforms is that #10-32 machine screws and #8-32 machine screws have the same pitch. So you can fit #8 bolts in a #10 hole and sometimes, they FEEL like they made good torque, because they engaged one side of the tapped hole, when they really have no tension capability whatsoever.
Reference the British Airways flight 5390 accident where the pilot got sucked 3/4 the way out the cockpit window and slammed against the side of the fuselage while a flight attendant clung to his feet and the co-pilot safely landed.
Also note that a British designed and built product was using US threadforms...
https://admiralcloudberg.medium.com/the-near-crash-of-britis...
https://en.wikipedia.org/wiki/British_Airways_Flight_5390
1. "They're more intuitive". They're not. You're just familiar with what 70 F feels like. If you're used to metric, 70 F is meaningless, but you intuitively know what 20 C feels like.
2. "Metric leads to lots of awkward numbers." All systems will fortuitously have round numbers in some contexts and awkward numbers in others. Customary units are different in that there are awkward numbers baked into the system. e.g. 5280 feet in a mile. 128 ounces in a gallon.
3. "It's too much trouble to change." You're already using metric units. U.S. customary units have, metrologically, been defined in terms of metric units since the Mendenhall order of 1893[1]. i.e. A meter is defined in terms of how far light can travel in a period of time defined by a hyperfine transition frequency of Caesium. If you needed to know exactly how long a meter is for a very precise measurement, a reference meter could be produced in a lab by aliens who have no idea what a meter is by using this definition. No such definition exists for a foot or yard. Nobody maintains physical reference yards (the old-school method) anymore. If you want those aliens to measure out a yard precisely, you tell them how to measure out a meter and then tell them 1 yard = 0.9144 m.
[1]https://en.wikipedia.org/wiki/Mendenhall_Order