why is the US not Metric

[xrunner]

[boffin]

whats the attraction to the use of old imperial measurement in the US?
here in Australia everything is Metric,  like most of the world.
why is the US system of measurement the odd one out?

Arrogance.

The same thing that is hampering the USA at pretty much every turn.  The thought that the rest of the world should bow down to their beliefs.

The UK is trying to enact the same arrogance, with the assumption it will boost them internationally, while it will have pretty much the exact opposite effect.

A number of posters are quite correct in that lots of industries are metric now, and just quietly convert it to feet and inches to appease the luddites.

Now if only we could get them to use YYYY-MM-DD..... instead of the insane MM-DD-YYYY

[xmetal]

I tend to use Fahrenheit for higher weather temperatures and Celsius for the lower ones. I use both feet and inches and metric, pounds and ounces and metric. I'm of an age when I initially was taught in Imperial but we switched to SI units whilst I was at school.

[Ice-Tea]

If you want to learn more about how historic measurement systems have deep repurcussions even in this space age:

https://aviationhumor.net/the-us-standard-railroad-gauge-is-4-feet-8-5-inches/

[NivagSwerdna]

... It's not much of a stretch to assume he would switch the country back to imperial if he could.

http://www.montypython.net/scripts/logician.php

[Ranayna]

What i find interesting in this debate is how the imperial units are handled in Germany.
In many things computer related, the inch as a unit is still very common. Harddisk and screen sizes are the current examples, floppy disk sizes where a thing in the past.
Then came the law some years ago, that you at first also had to include the size in centimeters, but could still primarily use inches. Then you had to priorizise centimeters, but still could include inches, and supposedly at some point inches where not to be used anymore...
As far as i know everyone still uses inches for harddisk and screen sizes 
Similar story with horsepower for cars.

So even i a country that has been metric for who knows how long, the tradition of old units is very very hard to beat.

[kosine]

You can't beat a good grunt in Anglo Saxon:

inch, foot, yard, pint, ounce, pound, etc

(yes, I know it's largely Roman grunts, but still quicker than the French alternative)

[Simon]

In italy all hose pipes were in inches and threads no doubt BSP.

When i bought my 43" screen i had to convert that to m to understand what I was actually buying. But I am sure that if you go to the factory that made my screen you will find all the drawings are in metric.

[Simon]

I don't understand horsepower. Again something that like all the roman measurements had to actually be defined at some point as 735W. i see that cars are now measured in kW.

[boffin]

What i find interesting in this debate is how the imperial units are handled in Germany.
In many things computer related, the inch as a unit is still very common. Harddisk and screen sizes are the current examples, floppy disk sizes where a thing in the past.
Then came the law some years ago, that you at first also had to include the size in centimeters, but could still primarily use inches. Then you had to priorizise centimeters, but still could include inches, and supposedly at some point inches where not to be used anymore...
As far as i know everyone still uses inches for harddisk and screen sizes 
Similar story with horsepower for cars.

So even i a country that has been metric for who knows how long, the tradition of old units is very very hard to beat.

What's even more fun are screws.   a 3½ hard disk uses #6/32 (US) screws, whereas a 3½" floppy drive uses M3 screws

[themadhippy]

The Americans cant even get there imperial units correct,why are there pints  smaller?

[Simon]

What i find interesting in this debate is how the imperial units are handled in Germany.
In many things computer related, the inch as a unit is still very common. Harddisk and screen sizes are the current examples, floppy disk sizes where a thing in the past.
Then came the law some years ago, that you at first also had to include the size in centimeters, but could still primarily use inches. Then you had to priorizise centimeters, but still could include inches, and supposedly at some point inches where not to be used anymore...
As far as i know everyone still uses inches for harddisk and screen sizes 
Similar story with horsepower for cars.

So even i a country that has been metric for who knows how long, the tradition of old units is very very hard to beat.

What's even more fun are screws.   a 3½ hard disk uses #6/32 (US) screws, whereas a 3½" floppy drive uses M3 screws

Standards change. At work we started to convert some obscure imperial screw to metric on projects as we got orders as the imperial ones while still available are expensive and directly replaced by M4 screws.

[AG6QR]

It's not just the US.

Virtually every Japanese camera made in the past 40 years has a tripod socket with a 1/4-20 thread.  That's 1/4 inch, 20 threads per inch. 

Why?  So they can fit on Italian and French tripods, which use 1/4-20 threads.

These same cameras generally have the focal lengths of their lenses measured it mm, so both systems are represented in most cameras.

[Simon]

It's not just the US.

Virtually every Japanese camera made in the past 40 years has a tripod socket with a 1/4-20 thread.  That's 1/4 inch, 20 threads per inch. 

Why?  So they can fit on Italian and French tripods, which use 1/4-20 threads.

These same cameras generally have the focal lengths of their lenses measured it mm, so both systems are represented in most cameras.

You can change what you measure focal lenght with at any time with no impact. But all acmera's and tripods have to be compatible so they have kept them the same as they always were. And the thread was probably devised before metric was widespread or the manufacture of metric threads was widespread. Thread manufacture would have changed after the countriues went metric.

there is a difference between wanting to continue to operate in an oudated system out of vanity and retaining things that are pointless changing but using a better system for the future. that is how things do slowly change for the better.

[Simon]

In the same vain pentax never changed their camera lens mounts, others did. Some people select the camera brand because they have an old lens that would cost a fortune to replace and is still seviceable. No one will buy a new camera for even a few thousand if it means changing a whole lens kit worth more than the camera body. Good telephoto lenses can cost more than the camera body.

[ajb]

Sigh... Until American children are taught metric the Imperial system will persist, simple as that. It's not about what is better, it is about what is familiar, and in the US the Imperial system is by far the most familiar one.

Metric *IS* taught in schools, or at least it was when I was a student, and I'm sure that science is still taught using metric.  The problem is that all of the day-to-day things are imperial, which as we see in this thread is something many other countries also deal with to some extent, so once taught it's easily lost.  The US is a big enough marketplace to sustain the production of imperial-dimensioned products, so it's not like there's a cost penalty, and the combination of being good enough and entrenched is what keeps it, well... entrenched. 

[ebclr]

Look at the regular wall switch in US, that is your answer

[German_EE]

Years ago I remember being told that the reason the USA hadn't converted to metric was the cost of retooling, imagine the cost of replacing all those lathes and milling machines, plus the drill bits and everything else.

However............................

Lots of US companies now have their stuff made in Asia, who are quite comfortable working with either system, and the cost of conversion has now shrunk.

[bitwelder]

Well, it seems Canada didn't want to miss any of the fun 

[AG6QR]

I don't understand horsepower. Again something that like all the roman measurements had to actually be defined at some point as 735W. i see that cars are now measured in kW.

I prefer to convert the power ratings of audio amplifiers and radio transmitters into horsepower.

You can really impress an audiophile by boasting that you own an amplifier capable of 1/3 hp output.

[vad]

You might as well ask when North America will join the 230 V world :-D Lots of advantages there (~3 kW available for common domestic appliances, lower final circuit currents leading to fewer fires and higher energy efficiency, eventual death of split-phase and weird stuff like high leg delta).

I would rather see the world adopting low-voltage DC residential electric circuits for lighting and electronics. At home I have about a hundred devices ranging from LED lamps to phone charges that don’t really need 120V, each with its own mains-operated LED driver or isolated SMPS (what a waste!), and only a handful appliances that genuinely benefit from 120VAC and two-phase 240VAC supply.

[tooki]

whats the attraction to the use of old imperial measurement in the US?
here in Australia everything is Metric,  like most of the world.
why is the US system of measurement the odd one out?

Ugh, this topic AGAIN? Why do people feel such a need to rehash this periodically, invariably coming from a place of arrogance at the "backwards" USA? As it happens, there are sound reasons for not bothering to switch to metric, it isn't laziness or obstinance.

First of all, of course, the premise postulated in the thread title isn't even true: while the US certainly isn't all-metric, it's not metric-free, either. Large soda bottles in USA have been 1/2/3 liters for decades, and practically all science and engineering is done in metric now. Medicines have been dosed in milligrams for ages. Temperatures, liquid volumes, weights and lengths/distances are the main things still done in US units.

But here's the little secret the arrogant USA bashers invariably ignore when discussing this issue: their countries aren't all-metric, either!

Here in Europe, a household hose fitting is highly likely to be defined in inches. (Like the one that connects a shower hose to the faucet.) Tire sizes are that bizarre mix of millimeters, ratio, and inches. Old people sometimes still ask for a pound of meat at the butcher. Diamonds are measured in karats. People discuss their TV sizes in inches. The tripod mounts AG6QR mentioned are in inches. And many more things may be given in metric, but actually defined in inches (like the spacing of pins on through-hole ICs. Yeah, it may say 2.54mm, but it's actually dimensioned as 0.1".)

I don't know Australia well enough to tell you which specific things in Australia still use imperial units, but I can say with total conviction that your claim that "everything is in metric" is untrue. Most, yes. All, no.

The Americans cant even get there imperial units correct,why are there pints  smaller?

The sizes of old units were not unified. The US and UK versions of imperial measurements diverged a LONG time ago, and had each been in use for a long time by the time their respective sizes were actually officially defined, independently of each other. (And in fact, throughout Europe, countless versions of the old measurements were used. They were NEVER unified.) So it's not Americans getting it "wrong", it's that EVERYONE had their own version of each unit before going metric, very much like how each country in the Eurozone had its own independent currency before switching to the Euro.

Years ago I remember being told that the reason the USA hadn't converted to metric was the cost of retooling, imagine the cost of replacing all those lathes and milling machines, plus the drill bits and everything else.

It's a real cost for sure, something nobody would make without their being a clear advantage to doing so. And over the years, as the advantages of using metric became obvious, many (most?) US industries did change to metric. American cars have been metric for decades now, for example. (And that transition remains a PITA for mechanics, who must maintain two sets of tools in order to service both younger and old vehicles. It's not just manufacturing that's affected by change, so is post-sales service, and compatibility. And ANY change involves risk. So there needs to be a serious advantage to make it worth doing.)

Lots of US companies now have their stuff made in Asia, who are quite comfortable working with either system, and the cost of conversion has now shrunk.

And as such, the metrication of the USA has continued unabated.


One of the best, least-biased explanations I've found on the reasons for the US not going fully metric is this one:

[Monkeh]

You might as well ask when North America will join the 230 V world :-D Lots of advantages there (~3 kW available for common domestic appliances, lower final circuit currents leading to fewer fires and higher energy efficiency, eventual death of split-phase and weird stuff like high leg delta).

I would rather see the world adopting low-voltage DC residential electric circuits for lighting and electronics. At home I have about a hundred devices ranging from LED lamps to phone charges that don’t really need 120V, each with its own mains-operated LED driver or isolated SMPS (what a waste!), and only a handful appliances that genuinely benefit from 120VAC and two-phase 240VAC supply.

So instead you want the greater expense and complexity of switching and protecting DC circuits and, translating to actual standards, the losses involved in ELV distribution.

Yes, this makes much sense.

[floobydust]

Living next to the USA, you memorize conversion factors and don't really care what the units are.
Many industries are exclusively Imperial, such as plumbing and piping, wire gauges, lumber.

I like Fahrenheit because it has almost twice the resolution compared to Celsius. Centimeters are harder to estimate compared to the King's foot or inches.

[wraper]

And many more things may be given in metric, but actually defined in inches (like the spacing of pins on through-hole ICs. Yeah, it may say 2.54mm, but it's actually dimensioned as 0.1".)

Glory to Soviet Union, they did not bother with that crap and simply used 2.50 mm pin pitch. Thus larger pin count ICs while being clones are not directly interchangeable.
Clone of 7400 http://www.kontest.ru/datasheet/unkn0wn/k155la3.pdf