why is the US not Metric

[tooki]

The one major area where pretty much every country in the world has not metricated is aircraft flight levels.

Note the altimeter in this Saab J35 Draken ("Höjd m"):

Please go back and read the whole thread, this issue was discussed at length a few weeks ago. Civil aviation and commercial aviation don’t use the same standards always.


To all the folks only joining the thread now: please read the whole thing. You are just coming in and restating what we thread veterans have all discussed long ago.

[tooki]

Must be an embarrassment to admit his location. 

Not the least bit.

I live in the world. And the world is metric. I'm really grateful that I am not forced to use any incoherent, cumbersome, obsolete, nonsensical, outdated, clumsy, crippled, lame, ill-contrived, quirky, elephantine, inelegant, graceless, ungainly, unwieldy, clunky, maladroit, bumbling, gawky, loutish, oaf, uncoordinated, uncouth, rustic, boorish, provincial, parochial, splay, lumpish, klutzy, incongruous, disparate, bizarre, erratic, haphazard, disjointed, rambling, antiquated, archaic, outmoded, bygone, kaput, moldy, moth-eaten, old-fashioned, totaled, sunk, floored, overthrown, bewildered, fusty, antediluvian, behindhand system of units.

And I pray every day for those who are not so lucky as I am.

You were asked what country you live in, and whether you have spent any time in USA.

As someone who has lived in USA and Europe, I assure you, neither system is a problem to live with. If customary units cause you an experience that trigger that combination of adjectives, then you have serious problems you should seek professional assistance for.

[bsfeechannel]

Wait... is that compass in degrees?  Not radians?  Surely that has been changed to the proper SI unit of radians by now.  We wouldn't want pilots using flight levels in 100 foot intervals and headings in degrees in the metric-only sections of the world.

("They'll take my degrees only when they pry my compass from my cold dead hands.")

Radians were considered supplementary SI units until 1995. After that, they were grouped as derived units. And the degree is a non SI unit officially accepted for the use with SI units.

[xrunner]

I live in the world.

Well the world is big. You can't live all over the whole planet at one time. What part of the world?

[Cubdriver]

The one major area where pretty much every country in the world has not metricated is aircraft flight levels.

Note the altimeter in this Saab J35 Draken ("Höjd m"):

Note the highlighted caveat in the statement above.  "Pretty much" /= all

-Pat

[KL27x]

^Well, no nation has metricated (as in changed to metric) their commercial air flight levels. There are some countries which had flight levels and altimeters in meters from the start. No country has switched from imperial to metric, here, although many have gone the other direction (largely after the war, I suppose). Most recently Russia, a few years back. (Cruising altitudes, anyhow; they switch to metric below like 8000 feet or something).

[Cubdriver]

Must be an embarrassment to admit his location. 

Not the least bit.

I live in the world. And the world is metric. I'm really grateful that I am not forced to use any incoherent, cumbersome, obsolete, nonsensical, outdated, clumsy, crippled, lame, ill-contrived, quirky, elephantine, inelegant, graceless, ungainly, unwieldy, clunky, maladroit, bumbling, gawky, loutish, oaf, uncoordinated, uncouth, rustic, boorish, provincial, parochial, splay, lumpish, klutzy, incongruous, disparate, bizarre, erratic, haphazard, disjointed, rambling, antiquated, archaic, outmoded, bygone, kaput, moldy, moth-eaten, old-fashioned, totaled, sunk, floored, overthrown, bewildered, fusty, antediluvian, behindhand system of units.

And I pray every day for those who are not so lucky as I am.

You pray for us uneducated heathens who use imperial units.  Well bless your heart.  That's comforting to hear, and will let me sleep more soundly tonight.

-Pat

[KL27x]

^That's a bit disrepectful. You have to admit, logic is implacable! Look at all that logic. That doesn't sound like a nerotic teenage girl acting out, at all. 

[SkyMaster]

The one major area where pretty much every country in the world has not metricated is aircraft flight levels.

Note the altimeter in this Saab J35 Draken ("Höjd m"):

Except for some communist countries, nobody in the world is using meter as an altitude unit in aviation.

[DBecker]

Wait... is that compass in degrees?  Not radians?  Surely that has been changed to the proper SI unit of radians by now.  We wouldn't want pilots using flight levels in 100 foot intervals and headings in degrees in the metric-only sections of the world.

("They'll take my degrees only when they pry my compass from my cold dead hands.")

Radians were considered supplementary SI units until 1995. After that, they were grouped as derived units. And the degree is a non SI unit officially accepted for the use with SI units.

Degrees are all the things you claim are bad about other non-SI units.  They are certainly completely arbitrary.  But they are commonly used because they are convenient, far more so than radians, and so entrenched that it would be very difficult to re-train everyone to use a different unit.  "Officially Accepted" means that pragmatic reasons over-rides the purity of the religion.  Well, the rest of the world is also metric-except-were-pragmatism-makes-sense, just with different trade-offs.

[Tepe]

The one major area where pretty much every country in the world has not metricated is aircraft flight levels.

Note the altimeter in this Saab J35 Draken ("Höjd m"):

Please go back and read the whole thread, this issue was discussed at length a few weeks ago. Civil aviation and commercial aviation don’t use the same standards always.

The Draken was neither civil nor commercial ;-)

To all the folks only joining the thread now: please read the whole thing. You are just coming in and restating what we thread veterans have all discussed long ago.

I was here from the beginning. It's nothing but entertainment that won't change anything. Utterly harmless.

[Tepe]

Not to mention that many common metric sizes for things are actually just the metric approximation of US fractional sizes. For example, in many industries one finds diameters of 3.2, 2.4, 1.6, and 1.2mm, which are the metric approximations of 1/8”, 3/32”, 1/16”, and 3/64”, respectively.

But nonetheless expressed in mm. The origin doesn't really matter.

Doesn't it, though? If the whole point is to standardize on metric production, then using things that aren’t metric (even if they’re expressed in metric) violates the metric-ness of the matter.

No, it really doesn't matter. The fact that the non-integral numbers 3.2, 2.4, 1.6, and 1.2 owe their origin to fractional inches means nothing. A 3.2 mm drill is just that, a 3.2 mm drill. Bigger than a 3.0 mm one and smaller than a 3.5 mm one. It doesn't bother people in metricated countries where expressing the diameter in fractions of an inch would be absurd. 3.2 mm specifies the size in the system people are used to and that is enough. It's the same drill we are talking about, we just call it something more meaningful to us.

Now, why we need those diameters in the first place is another matter of course - and it obviously has a lot to do with significance of products and standards originating in the US, where, as you have shown, those sizes make perfect sense.

[Gromitt]

The one major area where pretty much every country in the world has not metricated is aircraft flight levels.

Note the altimeter in this Saab J35 Draken ("Höjd m"):

Except for some communist countries, nobody in the world is using meter as an altitude unit in aviation.

You mean countries with the same level of communism as Canada? 
 

[KL27x]

It's the same drill we are talking about, we just call it something more meaningful to us.

To be honest, imperial drill bit sizes are not all that meaningful even to me. Anything beyond 8ths, I tend to just measure the screw/pin/dowel with calipers, then find the drill bit with calipers, lol.

There's also the time-tested trick of holding the screw and drill bit together, to see that the threads of the screw are just visible behind the silhouette of the drill bit.

Interesting some of the world calls 1/8" 3.2mm. I have seen, here, the metric size stated as 3.15mm, or maybe I just remember it wrong. The actual dimensions are 3.175mm.

[tooki]

The one major area where pretty much every country in the world has not metricated is aircraft flight levels.

Note the altimeter in this Saab J35 Draken ("Höjd m"):

Except for some communist countries, nobody in the world is using meter as an altitude unit in aviation.

You mean countries with the same level of communism as Canada? 

Canada is not among the 9 countries in the world that use metric flight levels, either exclusively or partly.

https://en.wikipedia.org/wiki/Flight_level#Metric_flight_levels

[SilverSolder]

It's the same drill we are talking about, we just call it something more meaningful to us.

To be honest, imperial drill bit sizes are not all that meaningful even to me. Anything beyond 8ths, I tend to just measure the screw/pin/dowel with calipers, then find the drill bit with calipers, lol.

There's also the time-tested trick of holding the screw and drill bit together, to see that the threads of the screw are just visible behind the silhouette of the drill bit.

You haven't lived until you've owned a complete American drill set, including Fractional 1/16" to 1/2" by 64ths,  Letter size drills A - Z, and Number size drills No. 1 - 60!

Really all these could usefully be rationalized to metric sizes, so you don't have to refer to a chart to figure out what is going on every time you need to drill a precise hole...

[DBecker]

It's the same drill we are talking about, we just call it something more meaningful to us.

To be honest, imperial drill bit sizes are not all that meaningful even to me. Anything beyond 8ths, I tend to just measure the screw/pin/dowel with calipers, then find the drill bit with calipers, lol.

There's also the time-tested trick of holding the screw and drill bit together, to see that the threads of the screw are just visible behind the silhouette of the drill bit.

You haven't lived until you've owned a complete American drill set, including Fractional 1/16" to 1/2" by 64ths,  Letter size drills A - Z, and Number size drills No. 1 - 60!

Really all these could usefully be rationalized to metric sizes, so you don't have to refer to a chart to figure out what is going on every time you need to drill a precise hole...

As the owner of several index set, I don't see any way to make them substantially simpler.  You'll still need a machinists handbook to figure out the proper one to use.  What is the proper size drill to use for a M10 fastener?  That depends on what you are doing.  If you are going to tap the hole, you need to consider the thread type, thread pitch, fit, tap type and material.  You might find that you need an R drill, which turns out to be more useful than "8.65mm" when that's not a common size.

The number and letter drill sizes are equivalent to the E series for resistors.  If you want a 5-ish ohm resistor, you select 4.7 or 5.1 ohms.

[SilverSolder]

It's the same drill we are talking about, we just call it something more meaningful to us.

To be honest, imperial drill bit sizes are not all that meaningful even to me. Anything beyond 8ths, I tend to just measure the screw/pin/dowel with calipers, then find the drill bit with calipers, lol.

There's also the time-tested trick of holding the screw and drill bit together, to see that the threads of the screw are just visible behind the silhouette of the drill bit.

You haven't lived until you've owned a complete American drill set, including Fractional 1/16" to 1/2" by 64ths,  Letter size drills A - Z, and Number size drills No. 1 - 60!

Really all these could usefully be rationalized to metric sizes, so you don't have to refer to a chart to figure out what is going on every time you need to drill a precise hole...

As the owner of several index set, I don't see any way to make them substantially simpler.  You'll still need a machinists handbook to figure out the proper one to use.  What is the proper size drill to use for a M10 fastener?  That depends on what you are doing.  If you are going to tap the hole, you need to consider the thread type, thread pitch, fit, tap type and material.  You might find that you need an R drill, which turns out to be more useful than "8.65mm" when that's not a common size.

The number and letter drill sizes are equivalent to the E series for resistors.  If you want a 5-ish ohm resistor, you select 4.7 or 5.1 ohms.

Sure, but say you need something slightly larger than an F size drill bit.  Will that next size up be a letter size, a number size, a fractional size, or even a metric size?

I ended up making a spreadsheet that translates all the sizes to metric, and sorting them by their metric size, then printing it out as a chart that I keep in the shop.  Nice and logical!

[CatalinaWOW]

I have the same sorting chart in decimal inches.  Yet another case where metric is slightly better, but not enough to force a change.

[SkyMaster]

The one major area where pretty much every country in the world has not metricated is aircraft flight levels.

Note the altimeter in this Saab J35 Draken ("Höjd m"):

Except for some communist countries, nobody in the world is using meter as an altitude unit in aviation.

You mean countries with the same level of communism as Canada? 

What are you talking about?

[Tepe]

The one major area where pretty much every country in the world has not metricated is aircraft flight levels.

Note the altimeter in this Saab J35 Draken ("Höjd m"):

Except for some communist countries, nobody in the world is using meter as an altitude unit in aviation.

You mean countries with the same level of communism as Canada? 

What are you talking about?

You called Sweden a communist country

[tooki]

No they didn’t. The “communist countries” they’re referring to are the actual countries that use metric flight levels. See the link I posted earlier:

The one major area where pretty much every country in the world has not metricated is aircraft flight levels.

Note the altimeter in this Saab J35 Draken ("Höjd m"):

Except for some communist countries, nobody in the world is using meter as an altitude unit in aviation.

You mean countries with the same level of communism as Canada? 

Canada is not among the 9 countries in the world that use metric flight levels, either exclusively or partly.

https://en.wikipedia.org/wiki/Flight_level#Metric_flight_levels

[Gromitt]

No they didn’t. The “communist countries” they’re referring to are the actual countries that use metric flight levels. See the link I posted earlier:

The one major area where pretty much every country in the world has not metricated is aircraft flight levels.

Note the altimeter in this Saab J35 Draken ("Höjd m"):

Except for some communist countries, nobody in the world is using meter as an altitude unit in aviation.

You mean countries with the same level of communism as Canada? 

Canada is not among the 9 countries in the world that use metric flight levels, either exclusively or partly.

https://en.wikipedia.org/wiki/Flight_level#Metric_flight_levels

Yes, but the picture is from a Swedish fighter jet with metric instruments.

[KL27x]

^ I think earlier in the thread, from November, Tepe posted that pic. And he explained that was "before" their imperialication. I think all the originally metric countries in Europe changed to imperial for ATC. I could be wrong. See Tooki's link, and you won't find Sweden and Canada on it. (Canada was never on it, AFAIK).

This is for altitude and vertical speed, to be clear. Visual range distances in metric countries is pretty universally communicated in meters and kilometers. (For fighter jets, I assume same applies to "radar range" when they are tracking other blips and firing missles at them). And I think most all countries use knots for horizontal speed.

[ebastler]

^ I think earlier in the thread, from November, Tepe posted that pic.

More likely than not, everything that gets written here has been posted earlier in this thread. 
'round and 'round we go...



Including this message, I'm sure.