thermodynamics and basic mechanics suck in US units. When I was in school I did all my non symbolic work in metric and then converted back to metric in the end. It was too easy to miss points by being off by 32.2.

The golden engineering rule of "always carry your units through" breaks down in some instances for SI.

Many places use mixed unit systems as customary.

The reason why we don't switch is a good lesson in what drives adoption in my opinion: need and not just convenience. It would be a giant PITA for alot of industries and the upside is only slightly less annoyed technical staff. People dont care that much about annoying others slightly less.

i'm still not 100% sure what a "Slug" is.

in college, our problems came at us in both flavors. the metric problems were a lot easier for sure. but i managed both. a miracle of sorts..

it would be very expensive to swap the USA over. california tried it (for projects), and backed out after a year of transition.

This

In medicine, there is a lot of metric. Doses are mg/kg, for example.

As stated above, tires are in inches all over the world, go figure

Really? Mine are 245mm in the front and 275mm in the back (on 17" rims mind you) ;)

Yep, that 17 inch diameter or whatever the diameter is, will be inches.

I always thought it was funny that the tire width is almost always in mm but the rim size is inches.

I have always wondered just how wheels are sold in China or Iran to local customers. Are those still sold in inches?

wasnt' there a space mission that failed a few years ago because someone didn't carry the units out correctly in the formula? Didn't convert from Metric to English or vice versa?

I think the English lengths, inches, feet, yards, miles, makes as much sense as scoring in Tennis.

They actually make a lot of sense
-The distance between your first and second knuckle on your index finger is an inch
-A foot is a foot
-An outstretched arm is a yard
-Two outstretched arms from tip to tip is 6 feet
-A span between outstretched pinky finger and thumb is 6 inches, or half a foot.

It goes on...

Hegemony. American.
It is sort of like biting your nose to spite your face.
Is there a truly valid reason?

I think that's called a dick, and it's 10"

Right?

Tires come in 400mm size. I'm not sure if there are any other metric sizes though.

I know there was this when Canada switched to SI.
https://en.wikipedia.org/wiki/Gimli_Glider

To be correct, they should use Fluid Ounces for volume.

One would think the little winkie crowd would be all for it ....afterall 4 inches is 10.5.....cm

Just thinking out loud, what if we appoint the day as the basic metric unit of time and then do centi hours, milli hours etc?

Things would get a bit out of hand when seasons change every .356 kilodays

It sounds a bit odd, but maybe because we are only so used to "non metric" time.

NASA- Mars Orbiter failed:
Nov. 10, 1999: Metric Math Mistake Muffed Mars Meteorology Mission | WIRED

Years ago, my dad sent me to order some window sash for a pre revolutionary war colonial. I said to the fellow, I need to order some custom windows. He asked me how I knew I needed custom windows instead of a standard size. Well, I said, it's a pretty old house. Well, he said, it's a pretty old standard.

He was right, they were a stock size...

Did ya ever notice that you snap that 10 mm socket onto a 3/8 ratchet?

Actually that is 9 1/4 mm....;)

Thats why women are such poor judge of distance. For years the've been told this is 6"...

EDIT:

I got that one wrong. Its supposed to be if you form an L with your thumb and index finger.

For the same reasoning you think a slotted screw is better than a Robertson. :D

I'm glad Roman numerals went extinct.


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I recall a story back in the day ('70's ) that the trade unions shot it down. Demanded that the gov fork over money to every union member to re-tool.
I have no idea if this is true, but it is plausible. Unions would have no such power today. If the corporations wanted it, they'd get it.

It's the Phillips Head I am not exactly nuts about - Robertsons seem to be more robust & resistant to driver damage.

Cheers
JB

My company's been using the metric system for the design and documentation of all new products for the last five years. All the fabrication shops we outsource to here in Silicon Valley are fully capable of building parts from drawings and CAD models made to metric dimensions. Converting over from imperial was a bit challenging in the beginning, but it all flows easily now. The most difficult part for me was getting the hang of applying precision tolerances to metric dimensions. Because I was so used to thinking in 'inches', I made some charts to help me quickly reference things like what .00005" is in millimeters. After that, I was good to go.

Well played! The Robertson screw head is the king of all screw fasteners.

Even the King has weaknesses. If you have to putty in the head and perhaps remove it again later, slot heads are much easier to clean.

Back on topic: I consider myself to be "Bilingual", I can work with either Imperial or Metric.

I was glad to see the reference to the "Gimli Glider". That is a perfect example of what can happen during the transition from one system of measurement to another. Once you are past that, Working with decimals is so much easier.
At the Interpretive Centre, I get people asking about the volume of water used in Acre-feet. It is so much simpler to take an 80 cm rise in water, over 10 sq km and work with the resulting 800,000 cu M.
But then I'm basically lazy.:D
Best
Les

Many moons ago I was doing my apprenticeship with a company that did the interior of Coke head office in Atlanta. A bunch of us were supposed to go down and install all the woodwork, our tools were sent down, but then we found out the boss screwed up the work visas. About a week later our tools returned and nothing was missing except every single Robertson driver and bit.

That was NASA's $125 million Mars Orbiter in 1999.

Nov. 10, 1999: Metric Math Mistake Muffed Mars Meteorology Mission | WIRED

In Canada, the Trudeau Liberals introduced the Metric System in 1970. We did, eventually, get used to metric. But the West has never gotten over Trudeau. :mad:

Think along the lines of the F35 jet's engine @ $14 million a pop. Or a Boeing 777 around $300m. That's what we still make here. And cars...lots and lots.

Back on topic, I have no damn idea why we didn't go metric, yet. Why do some Brits still talk in gallons and miles, at least in the media? Is a mix of systems in common use?

Fuel, for example, is sold in litres but otherwise measured in Imperial gallons (4.54L or 1.20095 US gallons). All distance and speed signs are in miles, but in smaller lengths they seem just as comfortable with m/cm/mm.

Speaking of Imperial gallons, I only recently found out that car advertisements in Canada show MPG (Imp.) numbers which look "better" than MPG (US), followed by the L/100km figure in small prints. If you don't know this, and because 99% of the time you talk MPG in Canada it's in US gallons, I think it's borderline misinformation. The rest of Europe also uses L/100km, but to me km/L makes more sense so I can quickly figure out how far I can get once the fuel reserve light comes on with 10L left or something.

I don't thinks so. I know nobody that when they talk MPG in Canada are talking US gallon. We use to have Imperial Gallon before switching to litres.

Any car display stickers or adverts, shows both, are base on Imperial Gallon like it was forever, so no misleading whatsoever.

Hey that's good to know! But I do know in my own circle of car friends we always talk in US MPG. Another example why life is so much easier with km's and litres :D

I have seen pictures of older milk or oil jugs labeled in all 3 units. I think that's quite nice that you just learn all those units eventually without trying too hard.

Slightly off topic, but relating to all different units/systems co-existing in Canada: I never got to learn French in grade school as I was already busy learning English first (ESL). But whenever we visit France now for example, I randomly remember the French words I saw on the bilingual packaging from Canada. So it's a very slow process, but it appears I'm learning by osmosis too :) Also the joke about Canadians who "write like Brits and speak like Americans with enough French thrown in to cause confusion" is very true, I cringe whenever someone says "fillet" here...

I'm retired Operating Engineer. I layed out the work and conducted the operations with the machines... For highway work; with any Federal funding there was a mandate that all engineering work, even, the writing on the stakes and sprayed markings on the ground had to be metric. Of course some operators had problems and I had to translate for them, however the most costly mistakes were made by the design engineers in the office. They would naturally do work in there head in tenths of a foot and then print that thought on the metric plan .... yes it was off by x times 3.28. These kind off errors were endured for years and I guess it was thought that eventually it would catch on..... All I can say is it was no problem for me. Actually the meter was less prone for making a one foot type bust..... But you would not believe how costly it was because of engineering slip ups (think Hubble telescope). And because of loss of productivity.... Think ordering dinner in a restaurant that only speaks Spanish. bob

a less NASA drill is to double a baking recipe in metric and imperial, you will be switching to metric

As said you are wrong about Canada using US gallons, we have (did) always used Imperial gallons and any Canadian MPG claims would have been in Imperial. The car manufactures would have been in deep poop as we have strict measurement laws. Oil manufactured/packaged in Canada will be in full liters, but if it's packaged in the US it by law must be labeled in metric and French. So a "liter" of US specialty oil that is really a US quart will be measured as .946 liters.

As far as conversion of MPG to L/100km this is a prime example of how you must totally forget Standard and think in Metric.
Does anyone remember the Clint Eastwood movie Firefox? The flashback scene to fire weapons he was told "You must think in Russian". Same thing "you must think in Metric".

Say your car gets 10L/100km (10 liters per 100 kilometers), just move the decimal place so 10L/100km = 1.0L/10.0km or 10/100km = 100L/1000km
Within seconds you know simply doing the math in your head you need 1 liter to go 10KM or 100L to go 1000km.

When you think in metric things become quite simple, because most of the time when calculating you are just moving the decimal place.

Yeah sorry, fresh off the boat immigrant problem! But I can't do 4.1L/100km into km/L quite so quickly in my head..? :D

Ask yourself a different question instead of converting. I need to go 100km, so how many litres so I need?

Oh, 4.1, so if I only wanted to go 10km I would only need 0.4.

But if I'm going 17.3km... just kidding, I get all your points ;)

Carry the one, divide by zero, stop for a coffee ;)

That's almost 860 Gunther chains!!


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