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why is the US not Metric
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vwestlife:
Anybody else remember these? Rulers marked in tenths of an inch, as a stepping stone to Metrication by decimalizing inches. They also tried to make the Metric equivalent easier to remember by rounding it off to "1 inch = 25 mm". (Hey, the Bible says Pi is 3.0, so isn't that close enough?)


KL27x:
Thanks, ebastler. We can x that off the list, i guess. Major reforms of their systems started in the Napoleonic era. As per Napoleans own preference for France (and what the N Koreans do), they did this by defining and rounding their units to metric. But you can give Germany credit for the "full" metrication in 1870, using the actual metric unit names.

By this standard, is NK metricated, yet?

Also, Portugal is said to have been the first country after France to adopt metric, in 1814. But this was limited in success, and they didn't let go of their native unit names until 1856. Fun fact, A canada was a unit of volume which was close to a liter, pre-1814. And equal to a liter from 1814-1856.   
ebastler:

--- Quote from: vwestlife on January 07, 2020, 08:22:26 pm ---Anybody else remember these? Rulers marked in tenths of an inch, as a stepping stone to Metrication by decimalizing inches.

--- End quote ---

That concept seems to have stuck in electronics, somehow.  ;)

Come to think of it, I had not even realized that all standard "inch" scale tape measures divide the inch into binary fractions!
Which is a brilliant concept, and leads to this:

https://www.youtube.com/results?search_query=how+to+read+a+tape+measure

Easily a hundred "How to read a tape measure" videos on Youtube!
And every single one of them refers to the imperial-scale version...
Wonder why?  ::)
Zero999:

--- Quote from: KL27x on January 05, 2020, 07:06:08 am ---Worse, as I showed earlier, the tools and/or industry standards can't always deal with these different prefixes. So you will use what you have. If your scale or caliper only displays in certain units, then that's what you choose from. Sometimes grams might be better. Sometimes grains. Sometimes milligrams. Depends what you are doing. No matter what you know in your head, the way you work will be affected by your available options when it comes to tools and standards.

Given all this, why are you so gungho about eradicating options other than metric?
--- End quote ---
Because having more standards is counterproductive and confusing. The more unambiguously something can be defined, the better. Fair enough, in informal situations it might suffice to say a handful, a hair's breath, a thumbnail etc. but when documenting something, it's better to use the same units, even if it may occasionally result in smaller or larger numbers, than one would normally deal with. Fortunately the SI system deals with large or small numbers with simple prefixes, to make reading and adding up much easier.

Notice how we have standard values for component values? We could have a lot more, but it makes life easier and components cheaper, as fewer values need to be made.
https://en.wikipedia.org/wiki/E_series_of_preferred_numbers


--- Quote ---"Milliturns" might be sliced bread for specific things. Grads might be great for certain things. But is it worth changing how airplanes navigate in order to switch to milligrees of lattitude and longitude? Is it worth retraining your artillery crew with new dope charts for distance and elevation and wind?* Changing geometry and scientific calculators to use 1000 milligrees for sin and cosine and tangent? To make a right angle 250? Do you have to "choose the best" and then use only one single system for every single function we perform using measurements? You will fix a lot of stuff that isn't broken; and you will introduce new problems just by sheer coincidence of seemingly innocuous differences that manifest in funny ways in specific applications, particularly where humans apply prior knowledge and experience and training. IOW, if the French artillery is hitting what they're supposed to, maybe let them keep using grads.
--- End quote ---
You've missed the point. Angles are all fractions of a circle. The argument for using powers of 10 isn't so relevant, as they are for measurements of physical quantities.

For example, if I gave someone a drawing, all the linear dimensions in mm and angles in degrees and asked them to scale it by a factor of 5, the angles will all remain the same. It wouldn't matter whether the angles were specified in, radians, gradians or milliturns, they would remain the same, as long as the x, y and z axis were all scaled by the same factor. Scaling the same drawing specified in feet and inches would be more tricky, for the reasons discussed previously in this thread, but it wouldn't affect the angles.
KL27x:

--- Quote ---scale it by a factor of 5
--- End quote ---
Can't you scale dimensions in any unit, though? Can you elaborate?


--- Quote ---Angles are all fractions of a circle... The more unambiguously something can be defined, the better.
--- End quote ---
So... having and using both grads and degrees makes it more or less clear/ambiguous?

Really, as long as you keep your usage focused for the task, you can use either in whatever the situation requires. French military might use degrees for navigation, but grads for artillery, for instance. But your whole post isn't making a lot of sense to me.


--- Quote ---Fair enough, in informal situations it might suffice to say a handful, a hair's breath, a thumbnail etc.
--- End quote ---
This is a pet peeve of mine. This is straight from the hive mind of english speaking europeans and college numbnuts. This is not how we use imperial in America. We use imperial for the highest levels of precision manufacturing/machining, just as much as borrowing "a cup of sugar" from the neighbor. Fractions, OTOH, are often used like this. E.g. quarter pound of pastrami. The fraction, itself, kinda denotes an acceptable toerlance, that as long as it rounds to 2/8ths it is close enough. Vs 125 grams of pastrami. Also the size of the unit can convey that, as well. Requesting 4 oz of pastrami would imply a tighter tolerance than 1/4 lb; it would be like asking 4/16th lb of pastrami.

When measuring stuff to sort into sizes, say a pile of sticks that isn't all uniform, you might round to nearest half cm, for instance. Or you might in imperial use quarter inches or half inches or eight inches, depending on how tight you want to sort them into multiple sizes. For grading or for the next process. So if you use an inch measure once a year, it might be confusing. If you use it for a repetitive task, it might be more useful/versatile, once you hone in on what you're using it for. 
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