General > General Technical Chat
why is the US not Metric
tooki:
--- Quote from: cs.dk on December 23, 2019, 04:23:56 pm ---
--- Quote from: tooki on December 23, 2019, 04:04:19 pm ---As for the yardstick: tue claim was that you could walk into any hardware store in Europe (i.e. not a specialist industrial tool vendor) and get dual-scale models. I think that’s untrue.
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It may depend on the importer for that specific country.. I've personally never seen a metric-only Mitotoyo caliper, analog or digital.
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Well, I just showed you Mitutoyo’s own catalog, so now you have seen them... ;)
Zero999:
--- Quote from: KL27x on December 23, 2019, 11:45:39 pm ---It's quicker to say a pound, though.
Quicker to say a half pound than a quarter kilo.
Quicker to say quarter pound than an eight of a kilo. Or 125 grams.
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And it's quicker to say a kilo than 2lb. What's your point?
Units are arbitrary.
--- Quote from: KL27x on December 23, 2019, 09:15:06 pm ---If you do any precision work in SAE, at least in my experience, you tend to think of it in decimal to thous. I.e. 1/8th steps are 0.125", .250", .375". .500", .625", .750", .875", 1.000"
Each 16th is 62.5 thous. Each 32nd is 31.25 thous, or about 30. But we have digital calipers; if you need this kind of precision, you are not using a tape measure, anyway. There's something "good" about using thousands/ths (000-999's), like metric users have found. And the inch just is the right size for this in common machining and manufacturing. Hundredths of mm would be the closest scale, but you only get 100 of them and they are more than double the resolution (so you only cover 1/25th of the range before adding decimal points (or commas that are in the wrong place); also this resolution is beyond inexpensive calipers, so the accuracy tolerance adds additional baggage.) Using thousandths of cm has its own problems; it seems like no one does that. Size of the unit absolutely matters to the context of what you are doing, IMO.
Look at it like this. If you handed an EE a caliper mechanism with no markings, just the electronics, and no measuring system existed, yet, and you ask him to make the thing show digits on it down to w/e resolution if has, he would have come up with something close to the order of thousandths of an inch. If you asked people to put useful markings on a measuring stick or tape to build things like homes and boats and boxes and baskets, well... that's how the inch evolved. The statute mile is a little weird. But, hey, the Romans built the best roads of their times, and it has worked out so far. They do what they are supposed to.
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Well I've always measured in mm for small things or decimals of a mm for tiny things.
Feet and yards are more plausible, as they were derived form measurements of the human body, but a metre is close enough to a yard. I can't see anyone reinventing the inch or cm. They'll probably use something like the width of their thumb or little finger for measuring things like small boxes. For extremely tiny things, a hair's breadth makes sense and is often use to give laypeople a sense of scale of microscopic objects.
https://en.wikipedia.org/wiki/Hair%27s_breadth
Cheap digital calipers where I work have a resolution of 0.01mm or 0.0005". We don't bother with expensive, more accurate calipers, but I've just Googled some which have a resolution of 0.001mm or 0.00005". I haven't seen any which measure in thou. In inch mode, they just tend to show a large number of decimal places, which is more difficult to read.
https://digitalmicrometers.co.uk/collections/digital-calipers/products/30-810-9516-sylvac-s__cal-evo-carbide-and-evo-caliper-0-150mm
I repeat units are arbitrary..
--- Quote from: gabinetex on December 24, 2019, 12:05:21 am ---Now, seriously, I confess that I don't really care why (or why not) the US is not metric... what really worries me, what keeps me awake at night, is why US ringbinders have 3 holes... I mean.. Why? Why? What in the hell is wrong with you people!!
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No I don't care either. I just find it amusing that many people seem to care and some Americans also appear to care about what the rest of the world think.
KL27x:
--- Quote ---And it's quicker to say a kilo than 2lb. What's your point?
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No it's not. "2 pounds" is 2 syllables. "1 kilo" or "a kilo" is 3 syllables. Maybe in UK, you say "I'll take kilo mashed potatoes?"
Wife to her hubby: No, dummy. Not that. We need the "5 pound bag." You've done this how many times? And you act like you've never been shopping before.
Thusly, the American wife can include more insults with the same breath while communicating weights.
"Five ten" (5'10") is easier to say than "one sixty" (160 cm) (And that's a nice case; could be "one seventy seven"; no one is seventy feet tall)
Not to mention, I don't see how you can say "quarter kilo" without sounding like there's a bag of French penises in your mouth.
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--- Quote ---Cheap digital calipers where I work have a resolution of 0.01mm or 0.0005".
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True, they display it. But they are not that accurate. Mine display 0.01mm, but they are only accurate to within 0.02mm.
--- Quote ---I've just Googled some which have a resolution of 0.001mm
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That's great. (They aren't that accurate, but hey, it shows numbers). And if you were working on something in that range, it would be great. For my uses, the range between 1 thous and 1 inch is more useful than 1 thousandth of a mm up to 1mm. 1 thous is the smallest unit I can reasonably give a crap about, in 99.99% of what I do. And it's also the smallest distance I can accurately measure, personally. (When I need more precision, I will have to buy new equipment. And when I measure the thickness of paint for a living, I might find thousandths of mm's are perfect).
Anything beyond that type of precision, the calipers is not very useful, anyway, no matter how many digits it will show.
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Units are arbitrary.
Yes, they are arbitrary. But no, that doesn't mean that any size unit is equally convenient for any given purpose. Refer back to how people like to buy stuff in pounds at the grocery store, even in the Netherlands. And not just because it's easier to say, but also due to the size of the unit; remember, they defied their government's attempt to make the pond = 1kg.
Same reason why no one here knows what the heck a rod is. (Except for bsfeechannel and v6kzgo). But to the worker that ever measured in it, it was more or less exactly right. You could say it is an "ad hoc" unit for a specific purpose. Like the blue line on your butter is 25 grams.
Another example is Russia's ATC. 100 feet is a good space for a flight level. This is pure chance, obviously. But Russia changed to feet partly because of compatability with neighbors, but also because this increased the air traffic they can handle by 50% more. They previously used 50m per flight level. That just happens to be larger than necessary, at least today. And 30m (or 33.3333333m) doesn't work as nice in our base ten number system. In the year 3000, maybe flight levels can be 10m, and metric will be more convenient in this aspect, of course. It's just chance, in this particular case.
But in the case of a tape measure or ruler, we can say that this evolved for the particular use case, and inches won (over the digit). If you like your tape measure to go 1-10 and than wrap around back to 1, and squint to read the little cumulative number, then cm are better for a tape measure. Some people might prefer inches, except for the fact that they think the world would end and they'd never be able to calculate 3 dimensional space in liters in their head ( :scared: oh no!).
BTW, fun fact. The average density of SEAwater is 64 lbs per cubic foot. Or 8 pounds per 6" cubed. Or 1 pound per 3" cubed.
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--- Quote ---I repeat units are arbitrary...
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Naturally. Please inform bsfeechannel of this. He thinks the speed of light is based on the meter.
Zero999:
--- Quote from: KL27x on December 25, 2019, 02:35:38 am ---
--- Quote ---And it's quicker to say a kilo than 2lb. What's your point?
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No it's not. "2 pounds" is 2 syllables. "1 kilo" or "a kilo" is 3 syllables.
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Fair point, but words are also arbitrary. For some reason metric units are two syllables rather than one, probably because they originate from another language, but some people are so lazy with their speech.
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--- Quote ---Cheap digital calipers where I work have a resolution of 0.01mm or 0.0005".
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True, they display it. But they are not that accurate. Mine display 0.01mm, but they are only accurate to within 0.02mm.
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Yes, that's true, but the extra digit can be useful for comparative purposes and as a check the instrument is working properly.
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--- Quote ---I've just Googled some which have a resolution of 0.001mm
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That's great. (They aren't that accurate, but hey, it shows numbers). And if you were working on something in that range, it would be great. For my uses, the range between 1 thous and 1 inch is more useful than 1 thousandth of a mm up to 1mm. 1 thous is the smallest unit I can reasonably give a crap about, in 99.99% of what I do. And it's also the smallest distance I can accurately measure, personally. (When I need more precision, I will have to buy new equipment. And when I measure the thickness of paint for a living, I might find thousandths of mm's are perfect).
Anything beyond that type of precision, the calipers is not very useful, anyway, no matter how many digits it will show.
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Don't forget, others have different requirements.
--- Quote ---BTW, fun fact. The average density of SEAwater is 64 lbs per cubic foot. Or 8 pounds per 6" cubed. Or 1 pound per 3" cubed.
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And the density of freshwater is simply 1kg per 1000cm3. Much easier to remember and work out. Sea water is a little denser, but for many applications, that doesn't matter.
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--- Quote ---I repeat units are arbitrary...
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Naturally. Please inform bsfeechannel of this. He thinks the speed of light is based on the meter.
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Yes and I could go back and counter all the examples you've posted with ones showing how metric units are often more convenient, but there's no point, because it depends on the situation. I could also go on about the advantage of being able to scale by 10 in metric, but you already know about that and that point has been beaten to death. :horse: An interesting thing is, there's a movement to get rid of cm and just use prefixes which represent multiples of three to the power of 10, so 1μm, 1mm, 1km etc. but cm is a convenient unit for many applications and chemists often use dm because 1dm3 = 1 litre.
tooki:
--- Quote from: cs.dk on December 23, 2019, 10:01:36 am ---
--- Quote from: tooki on December 21, 2019, 03:18:02 pm ---I have never seen a combination one in a hardware store anywhere outside of the Americas (as of now, meaning Europe and Thailand). Whether measuring tapes, foldable yardsticks, office rulers, or analog calipers, micrometers, etc, it’s metric-only by default.
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I've never seen an analog caliper being metric only. I have 5 different in my workshop, all with inches on the top.
Like this one;
(Attachment Link)
Tape measures with dual scales are also readily available here in Denmark.
https://www.hoffmann-group.com/DK/da/hodk/M%C3%A5lev%C3%A6rkt%C3%B8j/Linealer%2C-vaterpas/B%C3%A5ndm%C3%A5l-mm--tommeafl%C3%A6sning/p/462014
I can not really understand tires though. Their width is in millimeters, and the diameter is in inches. How weird is that?
The only full metric tire I know of, was fitted to Citroën CX.
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FWIW, I was at a big consumer hardware store yesterday, and while all the calipers were dual-unit (all el-cheapo), not a single one of the rulers, tape measures, yardsticks, etc had anything but metric on them.
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