Question for designers...

A compulsory conversion would never be accepted in the US, where anything foreign (and especially anything French) is seen as part of a vast communist conspiracy. First they put floride in our water to weaken our will to resist, then they convert all our maps to kilometers so the UN's black helicopters can use them to navigate around the US and seize our assault rifles.

Have you ever noticed that pinkos tend to drink wine (sold in liters), while real red-blooded American stick to beer (sold in pints/ounces).

Reply to
Bob
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Yes I can see that. I guess there are political reasons why reason doesn't prevail on the metric issue in America.

-- jc

Reply to
JGCASEY

It's because reason for the most part doesn't prevail in America. We allow personal emotions to rule over reason. We use fancy words like freedom to allow us to be stupid. Most people only care about how much of a pain in the ass it would be for them to have to learn a new system and since they don't see any personal gain in it for themselves, they reject the idea of converting. The fact that it would make the nation stronger as a whole in a increasingly international economy is something the average guy on the street refuses to care about. They bitch about jobs being lost to international markets but then refuse to do anything hard to actually become more competitive in those markets.

I don't see this attitude changing anytime soon. Maybe the increased international awareness the Internet is creating for Americans will make them start to think about these issues a bit more?

Reply to
Curt Welch

I do it in metric.

Because it's easier, and I'd rather focus on designing my robot than on multiplying and dividing by weird numbers like 12 (inches/foot) and 16 (oz/lb) and so on.

Because competent engineers can learn to deal with any units, especially with the help of computers, and it really doesn't matter that much (apart from the occasional lost billion-dollar space probe).

Reply to
Joe Strout

Good one! Love it!

Reply to
Wayne Lundberg

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Just rambling here... but my Machinery's Handbook has 2512 pages of very small print formulas for everything from the proportional formula, through trig and everything you ever wanted to know about screw threads, tapers, and proven mechanical wizardry in the inch/pound/hp world. Also enough on the SI to keep me awake at night. My Mechanical Engineering manual is just as prolific. I would hate to think of the mess we world be in if forced to convert all of that experience into something that really does not make that much sense...

I'm probably mistaken, but I believe the metric system was determined to be our national standard as far back as when Washington was our president. But it just is not that good to cause a national referendum on an apparently needless change. We are the world leader in technology. Let the rest of the world catch up to us by converting to imperial!

I was brought up with the metric system in my school, drafting, geometry and all that stuff. I started serious design work in the metric system and ended up pulling my hair out at the total confusion of that damned decimal point and where to put it. So I took up feet, inches, pounds and fractions. In my shop I have my little block with a quarter twenty tap and number seven drill along with my other fractional taps and either fractional drills or numbered drills or metric.

I think we should be able to use both systems. The metric system seems to do very well in the lab where really small stuff is measured and mixed. One cc is one gram and a thousand grams is a kilo. I can buy that. But in the shop... all of my machine tools are dialed in inches, my gears ratioed to cut threads per inch, and for me to scrap all of that just to buy something that does the same only in metric is really pushing it. So I have a set of wrenches in metric and another in inches. That's ok.

Wayne

Reply to
Wayne Lundberg

Wayne,

France IS the leader in technology (if you ask the French, that is). ;^)

Jeff.

Reply to
Jeff Shirley

This seems very odd to me. You find it easier to multiply and divide by numbers like 12, 16, and 144 than numbers like 10, 100, and 1000?

Indeed, I'd say we have to, in the U.S. at least. I tried to keep my tooling metric, and that lasted about a day, before I ran into something where I had to use imperial units, either to work with some part I had, or because the local hardware store only had an imperial part near the size I needed.

I don't have to like it, but until somebody passes a law banning all that imperial stuff, I have to live with it.

Best,

- Joe

Reply to
Joe Strout

It might rhyme, but it is not true "A pint of water weighs a pound and a quarter".

Reply to
pat.norton

I don't think Rich was talking about water.

Cheers!

Reply to
Mike H

A half inch is 1/2"; a quarter inch is 1/4"; a sixteenth of an inch is

1/16"; three times that is 3/16"... A half centimeter is 5mm; a quarter centimeter is 2.5mm; a sixteenth of a centimeter is 0.625mm. What's three times that? Plus your metric set probably only contains multiples of powers of 10... so most of these sizes aren't available...

Unit conversion usually only happens in higher-level design tasks such as "how long are 50 Xs" -- at which point the unit conversion only incidentally hinders an otherwise complex operation. Hence "scientists prefer" metric while "laymen prefer" English units. Besides, is 32.17 slugs/pound really harder to remember than

6.022*10^23 atoms per mole?

Decimal is a horrible base for practical use. The ancient Babylonians had it right - base 60 contains all the small primes, making all common fractions readily available.

But pi is the optimal base from a theoretical perspective -- it optimizes the tradeoff between how many symbols exist and how many symbols are needed to express a given value -- but nobody uses it since its difficult to represent integers... And binary is natural on computers...

- Daniel

Reply to
D Herring

I'm sure he was thinking metric... a litre of water weighs a kilogram

I think it's interesting to see the question was made in terms of our "old English system" as the US system has it's differences to what I know as the "Imperial Measure". I'm sure someone explained it so me, giving the English explanation with some nautical reference.

I'm in that generation caught between two measure, I use the SI units on the whole but will talk using a variety of measures - buying fuel it comes by the tank or 20 quids worth ;)

best regards, colin

Reply to
Colin Durrans

No, the rhyme is as stated, and in the US a pint of water at 20C weighs 1.04 pounds (he's right for Imperial gallons).

And an Imperial gallon weighs 10 pounds, by definition.

Well, we more-or-less inherited the units from the English (with the Imperial vs. US gallon being one of the biggest differences). I like to call the system in use in the US the SAE system, since nobody but the US really uses it anymore.

One thing that caught me by surprise when visiting England was how prevalent "miles" still are on road signs.

Reply to
Joe Pfeiffer

The public opinion that the metric system is easier to use because you just move a decimal here and there is totally unrepresentative of the nature of the beast.

The metric system has, from day one, forced one form of traditional measurement into a kind of decimal equivalent that requires a long stream of unwhole numbers (unholly?) for it to even resemble the original.

I find it necessary to imagine the end result of my calculations as viewed in the real world. Thus, when my end result for a shaft on the drive from a stepper to the wheel and my calculation shows ten inches, I can visualize ten inches. I can't visualize the hundreds of millimeters required to do the same in the metric system. I really can't visualize five ft. two and eyes of blue in centimeters, nor one hundred and ten pounds in kilograms.

So yes, to me it's much easier to tap for a quarter twenty screw into a piece of metal after drilling a number seven hole.

If there had been a solid reason to go metric, this country would have been the first to do so.

As we were in getting into the computer mania.

Wayne

Reply to
Wayne Lundberg

Awesome response Doctor Daniel! I must put this in my reference material for sure. Makes sense to me!

Wayne

Reply to
Wayne Lundberg

The rhyme is false unless 'world' = USA. That was what I meant.

Historically, yes, but that definition is legally obsolete. Old units are now legally defined in the UK by conversion from a metric unit. See:

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You would even see it slowly disappear from supermarket labels if manufacturers had choice. Unfortunately metric only labels are forbidden by US law.

Reply to
pat.norton

I read somewhere, sometime ago, probably when involved with the Joel Barker's thesis on paradigm shifts... that many Australians actually committed suicide when the nation was forced from the pound/shilling/sixpence monetary system to the decimal equivalent of the dollar.

We must remember history and the glories of change when Torquemada offered the Jews and gypsies the chance to become true believers or be burned alive... many chose to be burned rather than change belief systems.

Change can be the most difficult of all human challenges.

As we are seeing in the robot world.

My first industrial robot was a Hero from Heathkit to train my engineering staff in Mexico in automation technology and the future it offered us. We had a plant contest to name the robot so all personnel would be involved. The morning after the naming and demonstration of the robot we came to work and found it had been smashed. We call this "Sand in the gearbox syndrome" to this day.

This discussion on the metric system vs. US has been a true eye-opener. Thank you all!

Reply to
Wayne Lundberg

So, obviously, the rhyme is incorrect, because the "world around" includes the UK, and here, a pint is 20 fl oz, or a pound and a quarter.

It is (or was until recently) illegal in the UK to have road signs expressing distances in metres. I guess to stop people confusing the abbreviation "m"!

Deep.

Reply to
Deep Reset

Or 1/2 cm.

OR 1/4 cm.

or 1/16 cm.

3/16 cm.

If the sizes you need aren't available, you bought the wrong tools. I don't really get your point.

I don't buy it.

The only laymen that prefer Imperial units are the ones that never learned to work in metric units.

The fraction system used with inches is a base two system so you can only divide easily by powers of two. Decimal metric units at least makes it easy to divide by 5's as well. What's 1/5 of a cm? 2 mm. But what is 1/5 of an inch? Can't really do it easily.

The bottom line is that both systems have special cases that are easier than the other systems, but that in real life, not much happens in those special cases. You have something 6 3/16" or 15.7 cm and you want to divide it in 4ths and it's not trivial in either system. But at lest, with the metric system, you can pick up in $5 calculator and do the math directly since all our calculators work in decimals. But in imperial units, you have to play all games to figure it out like converting to decimal, then doing the math, and then trying to convert back to fractions, or dividing the inches and the fractions separately and adding the results.

The only thing worse is the mixed-base system of Imperial units. Base 12 for inches, base 2 for fractions of an inch, base 10 for feet.

Metric units are better because there is no conversions required since we do all our math in the decimal system already. Or the only conversion is learning where to put the decimal point instead of remembering what to divide by (12, or 4, or 8, etc).

If all you have to do is measure something, any system would work fine. You could put random marks on a tape and label them TOM, DICK, and JANE, then make it the standard and it would work fine. You just tell people the desk is 3 marks past JANE wide. But when you have to do math, like adding two numbers, or subtracting, or dividing a length into equal parts, then metric is a clear win because it's directly compatible with the decimal system we use for doing math with.

In most shop work, we learn how to do the math problems without doing math. Instead of measuring the width and subtracting another width, we just use the work piece like a slide rule and measure the first dimension in one direction, and the second dimension in the other direction so we don't have to do the math. As long as all work can be done that way, then we could just as easily use the TOM, DICK, and JANE ruler. But the minute you have to do math, Imperial sucks, and metric wins big time.

Base 60 would suck big time. You would have 60 symbols to memorize and the multiplication table and addition table you would have to memorize would have 3600 locations in it. The kids might get it all memorized and learn how to add by 6th grade if you were lucky.

Base 12 would probably be better than base 10, but again, the cost of converting the world to a base 12 system would be a real bitch.

I wasn't as impressed with the logic.

Reply to
Curt Welch

Like 3/16, for instance?

I think you mean e (base of the naperian logarithms). When I lived in Seattle around 1980, there was a group in town advocating the use of base e for all numeric representations. I was never able to tell from their literature whether they were the most batsh*t crazy loons in town (which in Seattle would be saying a lot), or one of the most long-lived, best-done parodies I've ever come across.

Reply to
Joe Pfeiffer

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