Imperial measurements

Except that the metric system blows.

You screw up and BAM, your answer is off by an order of magnitude. And then it becomes a big hunt to find the error. However, with the imperial system, you screw up, and then you search back through a list of easily recognizable conversion factors, none of witch is a 10 raised to anything.

Try using cups, gallons, ounces, pounds, inches or feet when doing science. See how long that lasts you…

Rod wrote:
"This is also supported by your reference to MPG. We use British gallons when we convert this, not American. (It gives a MUCH better result)"

Art wrote:

'How on Earth is this possible? Would you care to explain? I thought that conversions were just a matter of multiplication, division or (in the case of temperature) addition or subtraction followed my multiplication. I have never, ever heard of a system of measure that converted unreliably, so I'd be anxious to hear about it if there were one."

Alison was correct.

If I can get 10 litres per 100 km in my old Falcon, thats 28 mpg here or in the UK, but only 23.5 mpg in the US.

It''''s because you guys have those piddly little gallons over there. Of course, it does make your petrol look 20% cheaper than it really is!

Art wrote
"You're right that millimeters don't have a suitable equivalent in the US system, but in measuring things like the diamaters of nuts and bolts, tolerances of certain machinery and other things related to construction, machinery and generally building things, eighths, sixteenths, thirtiseconds, and even sixtyfourths of an inch are often used rather than millimeters (although metric units are also used for these same things). Using fractions of an inch works if you can keep it all straight, but can make conversion to metric quite a bit more complicated, and introduces a pitfall for error for people who are poor with math and trying to add these kinds of numbers up in their head!"

Of course the imperial exception to this is firearm calibre, but I know no one wants to go there!

Rod

JUST DO IT. I for one have no idea what the quart and pints etc mean. This mixed system nonsense must end. How many ounces are in a 2 liter drink. How many in a 1 liter or a .5 who knows and I don't care. Metric is just so much easier still can't believe we waste the time to teach both still. Oh and my kid is in second grade and is learning both systems.

> You screw up and BAM, your answer is off by an order of magnitude. And then it
> becomes a big hunt to find the error. However, with the imperial system, you screw up,
> and then you search back through a list of easily recognizable conversion
> factors, none of witch is a 10 raised to anything.

Curiously, I find it difficult to do any precision machining or other manufacturing using the imperial system: just what is 15/32" + 7/8"? As for the utterly hopeless system of fractional drill sizes … sigh.

Cheers

"Curiously, I find it difficult to do any precision machining or other manufacturing using the imperial system: just what is 15/32" + 7/8"? As for the utterly hopeless system of fractional drill sizes … sigh"

When you are restoring old vehicles, the fact we still have both around is good.Many is the time I've found I can get a tight fit on a corroded 13mm bolt head with a 1/2" socket.
Just remember that 1/64" is around 15 1/2 thou and it all gets easier. Every machinist should have his 'Zeus' conversion tables in his pocket anyway. You never know when that "letter" drill is going to come in handy for that metric one you broke. ;-)

Although less 'standardized', some imperial stuff is just 'right for the job'. Which is why even the continentals use British Standard Pipe thread. Whitworth threadform, with it's rounded root diameter, has more tensile strength for a given diameter than metric threadform. There are lots of examples…

> Every machinist should have his 'Zeus' conversion tables in his pocket anyway
Mine lives safely in the drawer with the micrometers and dial gauges…

As for letter drills – forget it! A full range of metric!

Cheers

"Don't worry, we only weigh babies in pounds. Once they get to be kids, we weigh them in kilos. Also, even though your baby weighed 7lb, she'll be putting on 100-200g a week."

Yes, but weighing babies in pounds annoys me. The usual rationalisation for it is that grandmothers don't understand metric – that may have been true 20 years ago but the majority of the current crop of new grandmothers – say 55 – 65 year olds – were in their 20's and early 30's when we went metric so they shouldn't need it. Some of the secretaries at work who are younger than me can't visualise a 3.2kg baby!

Oh, and the cobbler I take my shoes to loves that my Japanese shoes are measured in cms … he thinks it's much more sensible than having nominal shoe sizes.

My Zeus book lives in my top pocket!
As a machinist, i'm used to both sets of measurements. It depends on the customer wether i get handed an imperial or metric drawing to work from. I have a range of inspection gear, some metric, some imperial. I don't have a problem working in both.
I tend to 'think' in thous, and tenths of thous, for very small tolerances under a mm, but can visualise medium dimensions up to a metre easier in metric. I then visualise bigger simensions than that in imperial. Weird or what!
It didn't help being at school when the UK went metric. Being taught in imperial to begin with, then swapping over seemingly overnight to metric. :)

Timothy wrote, "Oh and my kid is in second grade and is learning both systems."

And very likely your kid's children will continue doing the same!

Until we make a complete change — meaning we start measuring everything in metric and ALSO change our containers to metric — folks won't be able to "internalize" metric completely. So long as we continue to buy milk in gallon jugs — it's a complete waste of time to train people to remember 3.78541178 liters! We need to convert our milk jugs to 4 quarts, period! Ditto for re-sizing everything else!

As mentioned, doing a wholesale conversion can be a terrific boost to our economy — similar to Y2K boosting IT expenditures — but a thousand times bigger!

Weighing babies in pounds anooys me too, but I suspect a lot of it if for comaprative purposes. Ya know, "your grandfather was a whopping 11lbs when he was born…etc…??

Some things will bever convert well to metric, and are entrenched in English speaking culture:

Penny for your thoughts-One cent for your thoughts (which coudn't happen in NZ as we no longer use one cent pieces)
Walk a mile in my shoes -Walk a kilometre in my shoes
Give them an inch and they’ll take a mile-Give them a centimetre and they’ll take a kilometre
Within an inch of his life-Within a centimetre of his life
Football-Meterball or 30cm ball
The whole nine yards-The whole nine metres
If I had a dime for every time-If I had ten cents for every time…
Nickeled and dimed to death-5 cented and ten cented to death (which couldn't happen in NZ as we no longer have 5 cent pieces)
A fifth of scotch-750ml of Scotch
Half pint-284 (or 237 for US) mls
A pint of blood -568mls of blood
Pound cake-454g cake
Animal pound-Animal 454g or Animal kilo?
Green acres-Green 0.4 hectares
10 gallon hat-37.8 litre hat

Hi Roger,

>As for letter drills – forget it! A full range of metric!

I am a machinist and I have access to metric drills 0.1 mm to 1 mm in 0.02-0.03 mm increments from 1 mm to 3.2 mm in 0.05 increments and up to 13 mm in 0.1 mm increments, I also have imperial, number and letter drills. I normally try to use the metric drills but sometimes to get the perfect fit I need to use the imperial, number and letter drills.

Hi Mike,

>My Zeus book lives in my top pocket!
As a machinist, i'm used to both sets of measurements. It depends on the customer wether i get handed an imperial or metric drawing to work from. I have a range of inspection gear, some metric, some imperial. I don't have a problem working in both.
I tend to 'think' in thous, and tenths of thous, for very small tolerances under a mm, but can visualise medium dimensions up to a metre easier in metric. I then visualise bigger simensions than that in imperial. Weird or what!
It didn't help being at school when the UK went metric. Being taught in imperial to begin with, then swapping over seemingly overnight to metric. :)

I am old enough to have started my machinist apprenticeship in imperial and finished it in metric, this was in Australia in the early seventies, I also do not have a problem with both systems but prefer metric, I still think some sizes in thous and tenths of thous rather than microns.

I still have and use my Scottish made Starrett 0-4" outside micrometers and my 2-12" inside that I purchased in 1971.

Tony

This is an interesting discussion.

I started school in 1972, the year that Australia introduced the metric system into primary schools so I have grown up with metric.

Australia maybe officially metric, but there are still hold-out bastions of imperial resistance. The old units are still used in everyday conversation to describe a host of different things.

Rod has already alluded to one: new-born baby weights. But there are plenty of others.

-Surfers generally use feet to describe wave heights.
-Fishermen/women still use pounds to describe smallish fish (say under 10lbs).
-Most service stations in Australia still use lbs/square inch in their tyre pump gauges.
-People still use feet when talking about their height (although weight is almost always in kg).
-Real estate is still popularly described in acres (especially in the purple prose in agent's windows).
-Beer glass sizes are still commonly measured in ounces.

Forty years of metric in Australia means that everyone is comfortable with using the system. So comfortable in fact that imperial units survive and live on in every day conversation.

I ws just at a SubWay restaurant, and the guy next to me asked for a 30cm Sub. The server behind the counter looked flumoxed, and asked "was that three chicken subs"? He said "no, a thirty centimetre sub, thanks". She looked blank and then asked "will a foot long sub be OK"?? He shrugged his shoulders and grunted affirmation. LOL.

T'would have been priceless if the server had just cut off the 4mm and wrapped up the rest.

"She looked blank and then asked "will a foot long sub be OK"??"

And NZ is officially metric!

That is one of the problems in Australia too – Subway is an US brand so everything is in Imperial measurements and they don't adapt their marketing for metric countries. One of the stupidest, most craven things the Hawke government did was allow American companies to use imperial in print advertisements in Australia – so now when I pick up Wild I see MSR etc ads claiming their tents "weigh just 4 lbs!!" Prior to that you weren't allowed to use imperial measurements in ads in Australia.

(For the record, the other stupid thing Hawke et al did was bowing to pressure from the US and allowing foreign sunscreen brands to advertise their sunscreen as "30+". Previously the max SPF you were allowed to claim was 15+. This was because SPF is a reverse logarithmic system, so SPF30 is not twice as effective as SPF15, which is what you'd naturally presume, it's actually about 1%. But claiming SPF30 – or SPF50 as I saw recently on some clothing – really is a great marketing tool … )