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Comment by capableweb | Hacker News Reader

Is US's consistent refusal to adopt something more common like the metric system the ultimate display of "Not invented here" syndrome? (I know imperial was invented by the British, but it's largely just the US left using it) Feels like everyone would be better off if the switch just happened already, as it'll happen one day or another. But they keep on fighting it off, for some reason.

Or does the imperial system have some advantage over metric (not including the fact that everything in the US is already using imperial) that makes it infeasible to change?

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> In 1793, Thomas Jefferson requested artifacts from France that could be used to adopt the metric system in the United States, and Joseph Dombey was sent from France with a standard kilogram. Before reaching the United States, Dombey's ship was blown off course by a storm and captured by pirates, and he died in captivity on Montserrat.

More seriously, blame the Reagan administration.

https://en.wikipedia.org/wiki/Metrication_in_the_United_Stat...

Thanks for that link! Seems to outline that there has been many attempts, some still ongoing, but not making a lot of progress.

Seems weird to fault all of these failed attempts to the Reagan administration, but I guess that's also an American thing to do, attribute issues to one group of people, not the one you're in, but "the other group".

> but not making a lot of progress

That part reminded me of Puerto Rico. Streets are marked with kilometer markers, rural addresses are street and km and hectometers. Also everyone miles for everything else.

I’m actually not sure which conversion failed.

And land is measured in "spanish acres" as well (Cuerda).

And two different scales of magnitudes (US-style "short scale", and "long scale" from Spanish colonial days), meaning two different meanings for millions and billions!

https://metricpioneer.wordpress.com/2014/01/05/long-scale-an...

And not a small difference! And people misuse it all the time.

We have a bit of a mess back home

It has ceased to matter. Most new products sold in the US use metric fasteners. A typical family has little or no use for imperial tools. There are some weird hold-out standards such as spark plug wrenches, but those have only one use anyway.

The imperial units are all defined in terms of metric units. There's no standard inch sitting in a vault somewhere.

Machine tools can switch from one to the other in a jiffy. Most design drawings give both units.

There are some odd things that still come in imperial units such as building materials, but a "2x4" is anything but 2 x 4 inches. Plywood is imperial length, but metric thickness, rounded to the nearest convenient inch fraction.

Food still uses imperial units of measure, most of the time, but people just eyeball the quantities and probably don't even know the actual amount. Most people can't look at a container and tell you if it's a pint or a quart.

I believe what happened is that the metric system was taught as a bunch of math, and people hate math. The big push came while I was in grade school, and I remember being taught: "The metric system is easy, all you have to do is some math." Metric was math and conversion factors. I remember a machinist telling me: "I hate metric because of the math." Yet he could add fractional inches in his head.

I agree with this but I assume you meant that most people can’t easily distinguish between a liter and a quart.

It’s even more confusing than that. They use the British system prior to imperial standardisation, so one has both US customary and imperial units of inch etc measurements. Which is why volumes and amount of sub units are different between the two.

> They use the British system prior to imperial standardisation, so one has both US customary and imperial units of inch etc measurements.

In modern parlance most of these should be identical under the 1959 international yard and pound whose entire point was to unify measurements which previously diverged slightly (as well as define them in metric/SI terms). US "Survey" units are really the pre-intenational versions.

The units which were not unified are mostly those of volume, so imperial volumes and US customary volumes differ quite a bit (plus the US has "fluid" and "dry" units): imperial units are the largest, then come US dry units (97% of imperial) followed by US fluid units units (83% of imperial).

having a unit of weight and a unit of volume share the same name is unspeakably stupid. why? WHY?

Apparently it's because a fluid ounce of water is about an (avoirdupois) ounce so, you know, super helpful reminder!

Like the pound being a unit of currency, a unit of mass, a unit of force, a unit of energy and a unit of torque (especially the latter two, who doesn't love having foot-pound and foot-pound being completely different things?)

If you're in an engineering discipline that does calculations involving mass and force, it's probably a good idea to work in metric even if you need to convert the final answer back. At least in my experience, it's way too easy to mess up when using pound force, pound mass, and slugs.

An imperial fluid ounce was defined (metric style) to be exactly the volume of an ounce of water. The reason for the change in number of fl.oz. in a pint was to make a gallon weigh 10 lb.

At least the pound referred to a specific thing in its currency form (i.e. a pound of sterling silver) and technically it’s foot-pound and pound-foot for energy and torque, simple!

And to confuse pound further: in Northern Ireland they pronounce pound and pint very similarly

It gets particularly confusing when people start comparing mpg for US and British cars, as the two gallons are not the same, I've seen so many arguments online where people are flat out comparing differenteasures and assuming they were the same.

> It gets particularly confusing when people start comparing mpg for US and British cars, as the two gallons are not the same

TBF mpg is a terrible unit to compare car efficiency regardless of which gallon you use. It's only more convenient to evaluate the range you have on a tank.

I'm obviously missing something. Why would distance travelled on a unit of fuel be a bad way to measure the efficiency of a car?

I know that such measures are always imprecise due to different driving styles/conditions etc. So what is a better way to measure the efficiency of a car?

> I'm obviously missing something. Why would distance travelled on a unit of fuel be a bad way to measure the efficiency of a car?

Because it has a sublinear relationship to absolute efficiency: an 11mpg car is significantly more efficient than a 10mpg car, while a 41mpg car much less so in relation to a 40mpg car: both provide an extra mile per gallon, which translates into a 10% and 2.5% increase in efficiency respectively.

> So what is a better way to measure the efficiency of a car?

gpm (aka L/100km which is what's used in most metric countries).

It's less convenient when you know how much fuel you have and want to know what distance you can expect, but it's way more convenient to compare efficiencies, as well as to calculate how much fuel you'll need for a given trip: the examples above are 21.4L/100, 23.5L/100, 5.7 L/100km and 5.9 L/100km. From this, it's obvious that the absolute gain in efficiency is much greater going from 10 to 11 (2L/100km economy) than from 40 to 41 (0.2L/100km)

Ah, I see, that makes a lot of sense, thanks for the explanation.

Well, even if the better unit is liters per 100km, you’d still face the same problems because the UK/US would be talking about gallons per x miles where they would still face the issue the poster described of differing units of gallons.

The point I was rather explicitly (if you go read the original comment) making is that mpgs are bad for comparing fuel economies regardless of differences in what is meant by "gallon", because it's intrinsically not a good unit for comparing fuel efficiencies.

I tried to explain this, but it turns out to be kind of hard, so instead I found a reference for you: https://www.bunniestudios.com/blog/?p=257

Basically, it makes it easier to compare fuel economy differences at different points in the scale because they become subtraction problems instead of division problems. This is because usually the amount you are going to drive is fixed, and MPG puts the miles in the numerator, while "gpm" puts the fixed miles in the denominator, I think.

Only if you don't drive for fun. If you do, it's a lot more useful to know how far you can get on a tank.

The original comment was about comparing fuel efficiencies.

But to your point: mpg makes it easier to know how far you can travel on a given volume of fuel, L/100 makes it easier to compare fuel efficiencies, and to know how much fuel you would need for a given distance to travel.

To me the latter seems generally much more useful than the former. The former provides an easier answer to "how far can I go burning this tank", which feels like a much rarer use-case than "how often will I need to refuel to my destination" (and "can I reach my destination on a single tank") for the general population.

The best way I've heard it phrased is that europeans 2ant to know much much fuel they need to get to their destination, while americans want to know how far they can go on a tank. Its obviously oversimplified/not relevant/other pedantic nitpicking but it captures the different relationship americans in general have with driving and their cars

Maybe this is because most people with cars in America (especially in the 1950's) were not worried much about the price of gas. Europe had much higher gas prices and was much poorer, so how much it would cost (how much gas would be used to get somewhere) was more important for planning than knowing when they would need to fill up again.

With volume per distance, you just need to divide the fuel tank capacity by the volume and then multiply it by the distance to get that. With distance per volume, you have to multiply the distance by the total volume of the fuel tank. The first calculation isn't that much harder than the second.

Realistically though, once you've driven the vehicle for a while, you pretty much know the total distance it will get in a tank regardless of the way fuel usage is measured.

> I know imperial was invented by the British, but it's largely just the US left using it

According to wikipedia, the US do not use the "Imperial System" but the "United States customary units" and they are not exactly equivalent, although they both derive from the "English units ".¹

Also, from the article: "The international foot is exactly 0.3048 of a meter". And it seems the international yard and pound are defined using the SI units as the reference.² (Edit: So by transitivity they also are defined using caesium-133 atom's radiation, light speed in vacuum and Planck constant.)

¹ https://en.wikipedia.org/wiki/Comparison_of_the_imperial_and...

² https://en.wikipedia.org/wiki/International_yard_and_pound

Basically, US Customary is english units pre Imperial standardisation.

Then in 1959 the major non-metric countries (I want to say US, UK, SA, AU and NZ?) unified their units under the "International Yards and Pounds". This metrified the definitions of various non-metric units.

So for all the units with an "international" version, "US customary" and "imperial" are now the same thing (though the pre-international versions might still be used in some contexts e.g. US surveyor units are, in fact, pre-international US customary units), and there are units which were not unified, most notably units of volume which remain different in the US and in imperial dominions.

Everything is already made to imperial, people are already comfortable using imperial. And the US is in an international position of strength in that we arent manufacturing amd selling things to other countries, we are buying goods made elsewhere, so we're the ones generating the demand. We dont need to standardize with the rest of the world in the same way, and so we dont bother with the effort. In the areas where standardization is required, such as research and development, you'll see that scientists already use metric.

The US actually originally planned to use metric, but if I recall correctly, the guy thomas Jefferson had invited to bring metric standards to the US ended up getting captured by pirates, so we never had the standards needed to switch and just didnt bother. But he time metrification was sweeping the globe, we'd already industrialized.

And one advantage that imperial has over metric - there are more multiples of 12. 12 is more divisible. A third of a foot is 4 inches, while a third of a meter is 33.333333333333333 etc centimeters

I never get this point. Why does it matter that 100 is not divisible by 3? What makes a third of a metre so special compared to 3 tenths? Most things do not want to fit neatly on integers on one scale, you need decimal points anyway.

In general contexts, either 30, 33, or 35 cm are perfectly acceptable. When accuracy is required, we use millimetres anyway (or micrometres, or nanometres, or angstroms...).

I really don’t see how more integers factors is an advantage that outweighs the clusterfuck that are conversion factors between points, inches, feet, miles, and the other stupid units, or the fact that a nautical mile is not a mile.

Besides, there’s absolutely nothing stopping anyone from using “a third of a metre” as a unit. For example, it’s common to have a line for 1/3 l in measuring cups.

Divisibility.

Using base-ten units, you can divide precisely by only 2 and 5. Not only are 1/3 and 2/3 not integer subdivisions of ten, they're not even precise decimals, but asre repeating.

Under base 12, there are precise subdivisions of 2, 3, 4, and 6 units. Under base 30 you can evenly divide by these as well as 10 and 15.

Under base 60 (a commonly used measurement base, a usage example will come to you in time), subdivisions are the above, plus 12, 20, and 30.

For practical use and arrangement, these can be highly useful capabilities.

In angular measure (base 360, 60*4), there are divisions which relate to trigonometric functions but not decimal scales. And to truly transcent the rational there are radian measures based on pi.

Under metric, you can still come up with precise divisibility, but only by disposing of the base-ten rationality. E.g., using 60cm or 60kg as a division basis.

Ultimately, base ten is an arbitrary anatomical accident.

Yeah, I know. That's hat I see in any discussion about SI with Americans, along with "a table spoon makes more sense as a unit because I've got one in my kitchen drawer".

But why does it matter? Why do you need 1/3 of a metre, and in which context would the 0.333...cm difference with 33 cm matter? This is smaller than the measurement error with common instruments we are likely to use in our daily lives. And there's nothing special about 1/3 m as a physical length, there's no reason why 1/3 m would be more useful than 0.30 m. I am not trying to be flippant, but I never got an answer to that question.

Also, the conversion factor matters only when you actually convert values, not when you measure them. Again, there is nothing stopping anyone from using 1/3 m, or 1/42 m, or 1/π m as units, or even giving them fancy names. As a matter of fact, this is exactly what you do when you use an inch: by definition 1 in = 127/5 m.

In practice the number of dividers is utterly insignificant, because using all the multiples of a centimetre (and millimetres if you're pushing it) is trivial. So getting a feeling for the difference between 32cm, 33cm and 34cm is very easy, and you end up with much better accuracy than if you limit yourself to eights, sixths and quarters.

It's also the same scale down from sub-atomic scales all the way to the whole planet (I understand the use of AU, light-years and parsecs, as the SI prefixes tend to become ridiculous at these scales).

Base 100! should make you happy. It's divisible by pretty much any integer you'd ever need. A bit unwieldy, but it really cuts down on fractions.

That's factorial, not emphatic notation.

Care to write the proposal?

To be sure, counting in base 93326215443944152681699238856266700490715968264381621468592963895217599993229915608941463976156518286253697920827223758251185210916864000000000000000000000000 would be a bit cumbersome.

After some reflection, I was actually thinking we should maybe use base 100!π³ just in case people end up working with spherical volumes. Open to suggestions.

sqrt(2), e and i as well, for completeness.

In the US, only building components are still Imperial measurements. US-made cars and aircraft have been hard metric for decades. Everything imported, other than building components, is hard metric.

Outside the US, almost nobody has non-metric tools. So Imperial stuff is unacceptable for export.

Home Depot creates the illusion that the US is mostly Imperial. They don't stock metric fasteners. One day I was in a Home Depot on a Sunday, and a Chinese woman was desperately looking for some screw she needed to repair some crucial appliance in her restaurant. It was metric, of course, and Home Depot didn't have an ordinary metric screw.

I buy metric screws from Home Depot all the time and have for years. How long ago did this happen?

What is a tenth of a pound?

How far is one thousand feet?

the advantage you sight is exactly problem why the international foot and U.S. survey foot exist and the issue mentioned in article happens.

it may be easy for us to think in fractions with repeating decimals, or irrational numbers ,it is super hard for computers which do Floating Point arithmetic, fractional arithmetic is not common from assembly, higher languages, or libraries we typically use to develop apps.

This is why engineering is always in SI, and errors happen in the interface between people refusing to change,

Given that most computing well happens in computers, It is lot more convenient for us change to a system computers understand, rather than keep a system we understand

> a system computers understand

Um, what? Computers understand base 2 (or 16 for compactness), not base 10. A centimeter is not 0.00999999977648258209228515625 meters.

Computers can be made to understand base 10 though, if needed. We do so routinely when amounts of money are involved so a cent is a cent, even though 1/100 is nonterminating as a binary fraction.

By that logic they can be made to understand base twelve (et al) just as well. And 0x64 cents is perfectly reasonable amount of money, but that's because it's a integer, not a fraction.

Brings up someone I read from an old crusty programmer, binary floating point is the wrong tool for most things. It's fine for scientific simulation work. But for everything else it causes no end of problems.

Floating point, binary or otherwise, is the wrong tool for many things. (Although (not-necessarily-scientific) simulation work is a very broad class of things.) If you're doing anything related to accounting, there is no excuse not to be using integers.

There are problems of fractional arithmetic in any base including binary. binary fractions are not base10 fractions and fraught with rounding errors, one more reason to not to use fractional arithmetic .

The U.S. foot mentioned in the article is defined as 1200/3937 of a meter which is 0.304800609601... depending on the precision you want the number will keep changing.

In Imperial you will find a lot of unit conversions like this which will need fractional arithmetic in base 10 like a foot is 1/3 yard etc. You will not find that in SI units as the base(10) and unit conversions (10) are the same making the definitions precise and avoid fractions between unit conversions

> engineering is always in SI

Sadly several significant NASA failures would disagree.

From quite a while ago. (The last failure I can think of related to units was over 20 years ago which means the design mistake was probably more like 25 years ago.)

a machinist told me that when he had to start doing metric stuff it was all the same dimensions, but converted to metric. so instead of 1/64" he had to mill 0.396875mm. even if everything new designed was in metric with fairly round numbers, you still have a ton of existing stuff designed with imperial units that needs to be taken into account and designed around. the result in some cases is that you get none of the benefits from metric or imperial. and your machinist needs to buy new equipment.

the main thing metric has going for it is that it's the same radix as our counting system and is consistant (as opposed to base12 and then base5280).

There are a few more advantages, especially when machining. There is a large system of standardized metric parts, e.g. washers, screws, etc. available on the cheap because they are needed everywhere. Whereas the US mess of screw sizes, denominations and threads produces a nonending headache of unavailability, high price and non-fitting but similar-looking parts.

Yes, the changeover will be ugly and involve redoing all your plans at some point. But after that you will see how much you are missing out...

there's a bicycle suspension company that's all-metric except for a single screw to adjust tension. apparently the metric screws had too steep of threads and didnt allow for the level of fine adjustment they wanted.

clearly we should create another standard to encompass all these cases and alleviate confusion.

There is a standard for metric threads with a finer inclination/pitch, no need to create anything special for the purpose: https://en.wikipedia.org/wiki/ISO_metric_screw_thread

> the main thing metric has going for it is that it's the same radix

I think this is the thing that is usually lost. Metric isn't about the units. No one cares whether the length unit is the size of a finger or a foot.

What's important is the radix, ease of conversion conversion and relation between the units of different dimension. A swimming pool can be 10m long and 5m and 2m deep. That means its volume is 100m^3 or 100 thousand liters and the mass of the water is a hundred tons. There are 3 coke cans in a liter (or kilo) so the pool could room 300k coke cans. Quick in-your-head conversions like that are so difficult in some cases with pounds, gallons, fl.ounces etc.

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.

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.

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.

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!

> 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/

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

Technically the problem here is using fractions.

> 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.

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

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

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.

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?

Base 12 metric should be a real thing. Maybe when we build self sustaining O'Neill cylinders we can use that opportunity to switch.

No. E.g. a foot is 12 inches, but a yard is 3 feet.

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.

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.

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.

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.

in the US, at this point, advocating for metrification is associated with a sort of odd, fringe type of political figure.

See the recent presidental campaign of Lincoln Chafee. Or the very humorous "Stonecutters' Song" from the Simpsons (https://www.youtube.com/watch?v=QoSLiHKrzRU), in which a parody of the Freemasons confesses to covering up UFOs, sabotaging electric cars, and suppressing the metric system.

> in the US, at this point, advocating for metrification is associated with a sort of odd, fringe type of political figure.

Tucker Carlson of Fox News thinks that metric system is a form of tyranny:

> CARLSON: Almost every nation on Earth has fallen under the yoke of tyranny -- the metric system -- from Beijing to Buenos Aires from Lusaka to London, the people the world have been forced to measure their environment in millimeters and kilograms.

* https://www.foxnews.com/transcript/can-the-us-continue-to-st...

Nothing new, with things going back to 1977:

> Dean Krakel thinks metric is more about Marxism than measurement. As director of the National Cowboy Hall of Fame in Oklahoma, Krakel is waging a war against metric on political grounds. In this 1977 clip from As It Happens, he says it reflects "the philosophical way communists want one of everything" - one world, one monetary system, one educational system and, now, one measurement system. "We're Americans, we're different. We're individualistic, we're strong," he says with passion.

* https://www.cbc.ca/archives/entry/is-the-metric-system-a-com...

And whatever some people on forums like this may think about it, there is zero widespread interest in a wholesale switch to metric in the US. Where there's an advantage to using metric like in science and engineering, people use metric (mostly). For day to day life, they mostly use US units and they work fine.

As someone else noted, even if you look at the UK, they use the metric system more than the US does, but they also still use imperial units in a lot of contexts--including some we don't use in the US like stones.

I have tools which are almost all customary units.

Sockets, Allen wrenches, calipers, wrenches, drill bits, taps/dies. All customary. Its just what's available used here.

Can't you convert the measurement from customary to metric, or from metric to customary? Why does it matter what system the tool was designed for?

Obviously anything that can be measured in customary can also be measured in metric.

In any larger workshop over here there is one toolchest usually marked in some bright and ugly color, all the tools marked in the same color, containing "Zollwerkzeug". That is, tools in inch sizes. You rarely need them, but on occasion you come across something from the other side of the pond where your 8mm wrench would just damage the head of your bolt. But often you can also get the job done with a monkey wrench.

However, this means that really changing over to metric, meaning also using international standards for tools, screws, bolts, wires, etc., needs buying new tools and material. I'm not sure how many metric tools there are in a typical US workshop, but I can imagine that they are not too common at the moment.

The majority of US consumer grade ratchet/wrench sets have both US and metric sizes. There are enough metric nuts and bolts in random things that you really do need both.

Need both, in USA - the at home toolbox in SI countries don't have this problem as they rarely bump into the odd-duck US measurements. The US system require to buy more tools - so I can work on most stuff (SI) and the some stuff (USA).

Buying two things to do one job - as is tradition.

If you start from scratch, sure.

But if you're e.g. repairing existing equipment, then the customary and SI units are incompatible. Say, a 1/4 inch bolt head is too large for a 6 mm wrench, but too small for a 8 mm (which is typically the next step up from 6mm).

For this reason I had to buy some wrenches in customary units to fix a lawnmower engine.

> But if you're e.g. repairing existing equipment, then the customary and SI units are incompatible. Say, a 1/4 inch bolt head is too large for a 6 mm wrench, but too small for a 8 mm (which is typically the next step up from 6mm).

Where is the problem? Buy a 6.35mm wrench for your 6.35mm bolt head.

Then you're left with these wonky sizes that are only there because they were designed to be a round number in another unit.

The US uses different bolt threads than the rest of the world. Just today I had to buy an 1/4 inch long 8-32 threaded screw to fix our stroller. The 8 refers to a standard diameter in the US system, and the 32 means "32 threads per inch".

How does this work now that almost all products are global and most are manufactured outside the US? Does a Ford engine get designed in both customary for in the US and in metric for the rest of the world?

At this point, new cars are 100% metric, with the exception of tire sizes, which are still inches (usually integer inches, sometimes half inches too), and have been for a pretty long time (switching seems to have started in the late 80s / early 90s where cars would have both types of fasteners, and by the end of the 90s, it was just metric). This probably has something to do with the increasingly global supply chains, and increasingly global parts suppliers.

Oh, and the speedometer and the odometer. The digital ones are probably counting meters and converting though.

It’s funny that the super-American icon of the car has switched but that this hasn’t caused everyone else to switch. My image of America is a parent and child working on their car together in their garage. Would have thought that would have gotten everyone into metric over the last few decades.

I mean, over the last few decades, working on cars is harder. Maybe in part because the fastener sizes are tricky, but mostly because things are much more complex.

Anyway, the US already has the metric system for things that matter; science and most manufacturing. For things with wide reach, like distance signs, and speed limits, and quantities at the grocery store, those tend to be in customary units, because the switching cost is too high for the benefit.

As other comments have said, Why bother? Whether I use miles or km on the road is pretty much irrelevant. Everyone’s kitchens are filled with mostly US measurement stuff. And truth be told if I’m weighing things I switch effortlessly between grams and ounces on my digital scale. Some people may but I’ve no particular ideological position on it.

Car stuff is usually metric, in my experience.

Plenty of things end up as imperial elsewhere in the world, though. My lathe and milling machine dials are graduated in thous (thousandths of an inch). I've seen those on YouTube channels in other countries.

The exact sizes are all arbitrary, in practice the are all in even fractions of some base unit: imperial an metric tools simply fit together poorly because they’ve been made in slightly different sizes

It's political, just like wearing masks to prevent covid infection has become politicized. Both masks and meters have become associated with left-wing intellectual elites, and so the right reflexively rebels against them.

EDIT: to all the people downvoting this comment without explaining why: you are actually proving my point.

You forgot the step where left-wing intellectual elites ridiculed people for wearing masks as it "doesn't protect anyway and creates a false sense of security". If anything, I would imagine masks to be a prepper thing, so I would have thought more popular on the right, but I guess there is no logic anymore.

> If anything, I would imagine masks to be a prepper thing, so I would have thought more popular on the right

You can _think_ that, or you can look outside at who’s protesting masks and which president is discouraging their usage.

Masks don't protect the person who wears them, they protect the people around the people who wear them, so they only work if everyone wears them. In the early days of the pandemic there weren't enough masks for the general public (because the Trump administration had sent a significant portion of the U.S. supply to China [1]) so there was a desire to reserve the limited remaining supply for health care workers.

Comments like yours which obfuscate basic facts like this are a perfect example of the kind of politicization I'm talking about.

[1] https://www.snopes.com/fact-check/us-tons-ppe-china/

Also we didn’t know that masks protect. At the time the thinking was the virus was spreading through surfaces so the guidance was to wipe down all surfaces, etc.

But since then we’ve discovered that the overwhelming majority of spread has been due to direct transfer of the virus usually through water droplets.

The virus is too small for masks to stop them. But most masks are good enough to stop water droplets.

Of course masks protect people who wear them. Perhaps the protection is "minimal", but that's not zero.

Oh, good grief. So I left out the word "mainly". That in no way refutes my point, which is that this entire discussion has been politicized. And the fact that you are picking at such a tiny nit just further proves my point.

I agree it's been politicized, which is why being precise is important. The fact that medical authorities made claims that blatantly contradict all common sense and basic scientific facts erodes the public confidence. This has happened numerous times since the pandemic began.

I'm Canadian, so I frankly have no direct stake in US politics, but if people on both sides can't agree on basic facts, then there's no hope.

Finally, I don't think the protection afforded is really all that "minimal" for numerous reasons, but the degree of protection wasn't the main thrust point of my post so I didn't (and still don't) want to go into it.

The medical community has war gamed pandemics for years. I wasn't surprised to see the "masks don't help" line because that's been part of the lessons learned from these war games.

They knew there would be panic buying so they had this bit of subterfuge ready to go when a pandemic hit. The problem is that it is a bee-sting solution: one use only. Now that COVID19 has turned out to be far less dire than predicted, that bee-sting solution is gone and wasted. When we get a much more deadly pandemic, and we will, that tool will no longer be available. It's a shame it was used for this situation.

Sure, we could learn from this to always have enough PPE in stock but once this pandemic is over, every year there is going to be pressure on budgets on every level to cut the size (and cost) of PPE storage until it eventually shrinks down to what it was when this pandemic started.

If the medical community wants to regain some of its credibility it needs to stop circling the wagons and pretending this wasn't an intentional but well meaning lie they told the public. The longer it takes them to stop spinning the issue, the longer it is going to take them to regain the trust of the public, which will be detrimental to public health.

> I didn't (and still don't) want to go into it.

And yet you just did.

"Going into it" is an idiom for presenting and deconstructing an argument, in case you weren't aware. I asserted my point, I didn't argue for it.

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