ECN Forum
Posted By: PEdoubleNIZZLE Metric Inches - 08/14/06 09:30 AM
I had a weird day on Friday at my work place (at the home center with the blue sign). Since I broke my foot in two places, I wasn't supposed to work because I can't wear a regular shoe. But since OSHA doesn't care about what I do at my house, I decided it was time I replaced my porch light, so I went shopping where I work. A customer recognized me as an employee and asked me to cut some wire. I told him I can't do it for him, but I'd get someone to help him (since I'm a nice guy). I got the electrical associate, and he asked the customer what he needed. "I need some 12 gauge thhn for 3 phase... you know red, black, blue, white, green." We knew what colors he needed, but he might have thought we didn't know (those are also the only colors we stock at our store. You want purple? We don't got no stinkin purple! [Linked Image])

So the associate asked him how long he needed it. The customer said "I need 500 metric inches, that's what I measured."

The associate was at a loss for words. He thought it was a practical joke, so I jumped in and asked if he meant centimeters. "No, my tape measure says 'metric inches'" I asked to look at his tape measure. It actually read "metric" on top and "Inches" on the bottom. It seemed to be a no-name dollar store that suffered a language barrier. I asked him if he used the top or bottom to measure, and he said the top. I told him, "Sir, just to let you know, those are centimeters," to which he said, "Don't give me that, I know how to use the mectric (that's how he pronounced it) system." So we gave him 17 feet of wire. I told him, "Since we measure in american feet, I have to give you 519 metric inches." He was upset about the whole ordeal, but the associate and I shrugged it off. As soon as he turned the corner, we were laughing so hard that I forgot about the pain in my foot.

I wonder how many metric amps you can put through #12 american wire. It's also good that my store has a no liabilty policy. If someone doesn't know how to use a system of measuring, I'd hate to know what they're wiring up that's three phase.

Eidted for disclaimer: Not knocking the metric system, as I am fluent in both. Just making fun of the customer with the "metric amps" part.

[This message has been edited by PEdoubleNIZZLE (edited 08-14-2006).]

[This message has been edited by PEdoubleNIZZLE (edited 08-14-2006).]
Posted By: SolarPowered Re: Metric Inches - 08/14/06 07:28 PM
Just to add a bit of trivia, the ampere is a metric unit, as are the volt, ohm, farad, etc., etc. Also, the inch has been officially defined to be 25.4 millimeters since sometime in the 1800's, so the inch is also pretty much a metric unit. As are the foot, yard, furlong, and mile. [Linked Image]
Posted By: trobb Re: Metric Inches - 08/14/06 07:58 PM
I know there are engineers on the forums that know this already, but here's another oddity. The pound is a force measurement, actual weight is a 'slug'. Divide pounds by 32.2 to get slugs. (Acceleration due to gravity). Looks like we don't even have to leave the 'American' system to get strange quirks.
Posted By: SolarPowered Re: Metric Inches - 08/14/06 08:20 PM
We actually play with pounds force, pounds weight, and pounds weight. That's how you end up with the bizarre oddity that the specific impulse of a rocket engine is measured in "seconds" in English units, because it's "pound(force)-seconds/pound(mass)", where they cancel out the pounds to get "seconds". Whereas in metric it's "kilonewton-seconds/kilogram", which is also sometimes expressed in the reduced form "meters/second", a much more intuitive unit.

[This message has been edited by SolarPowered (edited 08-14-2006).]
Posted By: Alan Belson Re: Metric Inches - 08/14/06 09:43 PM
The metric faradiddle started here in La Belle France 200-odd years ago. The French Revolutionaries wanted to get rid of everything associated with l'ancien regime, so they changed everything possible, just to make sure it all couldn't come back!
They cut off the heads of the Royal family, the aristos, the landowners and anyone else vaguely bourgeoise they could catch, just to make sure.

They invented the guillotine for 'humanitarian reasons', [ although the increase in 'production' also came in handy, as it happens ].

Now don't start feeling sorry for the 'old regime'. They were as vindictive, cruel and blood-thirsty bunch as one could ever imagine. Nobody but the poor paid taxes.

Sébastien Paturel was one victim from my village. A farm laborer aged 19, in 1746 he walked to Mayenne for an evening out with 4 mates and was arrested as a 'salt -smuggler' under a new law designed to stamp out the practice. [ The tax on a £3 box of salt was £58! ]. Sentenced, though plainly innocent, to 5 years in the slave-galleys at Marseilles, he was welded into 28lbs of iron manacles and neck-weights and force marched 400-odd miles, but not before he had 'GAL' [galley-slave] burned into his forehead with a branding iron. He must have been one tough kid, because he survived. 5 years later he was cut out of his irons, had 'liberté' re-branded over the top of 'GAL' [!] and walked home. He married soon after. He died in 1790 aged 63. His descendants still live here.

So, where were we? Oh yes, they changed to cm, kg, metres and kilometers, litres and hectares.
At one point, they even decreed 10 hour clocks. 10 hour days each of 100 minutes each of 100 seconds. They invented the 'metric calendar'. 12 months of 30 days each divided into 3 decades per month, [ ie. 10-day 'weeks' ] with 5 or six additional days tacked on the year-end [ because they couldn't slow the earth down! [Linked Image] ]. Year '1' was 1792 [First Republic], but Napolean abandoned it all 14 years later.

They bumped off a few of the brains too, like Lavoisier.

Then they all killed each other, just to make doubley sure! [Linked Image]

Which was handy for Napolean Bonaparte.
Who, by the way had Scottish ancestors.

Actually, they did'nt change everything, not quite.
Since pipe-threads were already standardised and all the plumbers had imperial threading tools, they kept the sizes the same but changed the nomenclature.
So, 1/2" BSP = 15mm x 21 and all metric pipe threads will fit imperial ones.

The pouce[inch], pied[foot], and livre[pound and also a £ sterling ] live on in common use by country folk. Heck the old boys round here still talk in ancien Francs and they've been gone 40 odd years!


Alan
Posted By: SteveFehr Re: Metric Inches - 08/15/06 02:17 AM
Quote
I know there are engineers on the forums that know this already, but here's another oddity. The pound is a force measurement, actual weight is a 'slug'. Divide pounds by 32.2 to get slugs. (Acceleration due to gravity). Looks like we don't even have to leave the 'American' system to get strange quirks.
Ah, I think you mean "mass" [Linked Image]

Quick! Can someone convert the temperature from Rankine into Celsius for me??
Posted By: togol Re: Metric Inches - 08/15/06 02:48 AM
Alan,
you always manage, with a grin, to teach history .......
Quote
....At one point, they even decreed 10 hour clocks. 10 hour days each of 100 minutes each of 100 seconds.


Thank you
Posted By: gfretwell Re: Metric Inches - 08/15/06 02:50 AM
Well it's about 85 f here right now, that's 29.4 c or 544.7 r
Posted By: gfretwell Re: Metric Inches - 08/15/06 02:55 AM
Rankine is the Fahrenheit equivilent to kelvin in celsius. 0 is "absolute zero"
Posted By: pauluk Re: Metric Inches - 08/15/06 01:05 PM
Should we even get into the difference between the U.S. pint/quart/gallon and the Imperial pint/quart/gallon? [Linked Image]

I like the "metric inch" concept though. Next time some branch of our dictatorial government insists that information has to be supplied in metric units I'll just measure in good old feet, inches, pounds or ounces and just tell 'em it's the "British metric system." [Linked Image]


[This message has been edited by pauluk (edited 08-15-2006).]
Posted By: Alan Belson Re: Metric Inches - 08/15/06 04:37 PM
In for a penny, in for a pound, Paul!...
Originally, 'gallons' meant a multitude of quantities, depending on what was being measured; corn, wine, ale etc. In 1706 during the reign of Queen Anne, [ftatute #5], the liquid gallon waf redefined af 231 cubic inchef, or 3" x 7" x 11" exactly.
This is the US gallon.

In 1824, [ William IV ] the British decided to parody the French metric idea, [ oh! not them again! [Linked Image] ] and redefined the Gallon as 10 pounds of water measured with brass weights at 30" of mercury barometric pressure and at 62 deg F. ambient.
Some slight later tweaks were made, but:-
This is the Imperial Gallon.

These are liquid measures. There are still US 'dry' gallons for corn etc. in current use I believe. I'm not sure the Imp. Gallon is any longer a legal measure in the UK?

Alan

edit to correct number.


[This message has been edited by Alan Belson (edited 08-15-2006).]
Posted By: pauluk Re: Metric Inches - 08/17/06 12:46 PM
Quote
I'm not sure the Imp. Gallon is any longer a legal measure in the UK?

Possibly not since gas pumps were changed to liters a few years ago, but you're getting into a big debate there which has formed much of the argument over the "Metric Martyrs" case (traders prosecuted for continuing to sell their wares in English units instead of metric).

See the various articles here for details:
http://www.bwma.org.uk/
Posted By: gfretwell Re: Metric Inches - 08/17/06 04:05 PM
I imagine the US will be the last country using the "English" units. There are still plenty of folks here who think it is a commie plot or something "French".
I have started using "C" for my pool temperature, mostly because the lab grade armored thermometer is marked that way. It is easier though. 27 is too cold and 31 is too hot. I am working on a floating thermometer that outputs on 4 LEDS.
27 and below blue
28 yellow
29 green
30 and above red
Posted By: Ann Brush Re: Metric Inches - 08/22/06 06:02 PM
OK here is one I love:
What is heavier a pound of feathers or a pound of gold? - Oh we have all heard that one - The answer is neither right! WRONG! A pound of feathers would be measured in pounds avoirdupois (16 ounces to the pound - 453.6g) while the gold would be measured in pounds troy (for precious metals) at 14 troy ounces to the pound (373.2g). Just when you thought you had heard it all.
Cheers Ann
Posted By: Texas_Ranger Re: Metric Inches - 09/01/06 10:22 PM
I recently did a plumbing job for a friend... I had to buy: 25m of 15mm copper pipe with associated solder fittings, for connecting things: a 1/2" spigot with a 3/4" hose connector, several sets of 15mm solder to 3/8" and 1/2" threaded adaptors, and for the boiler two 3/8"-1/2" adaptors.

Or at school... once we needed a Whitworth threading set... metric threaders exist by the dozen, but the entire technical school of 3000 students (ustria's largest school) has only one Whitworth set...
Posted By: mbhydro Re: Metric Inches - 09/02/06 02:52 AM
Never heard of Whitworth thread size, is that a speciality measurement?

When I was in high school in the mid 70's Canada was just changing from inches / feet to Metric so I am sort of at home in both.

My nieces that are in school now all use metric and convert to Imperial only when necessary.
Posted By: pauluk Re: Metric Inches - 09/02/06 10:35 AM
Quote
Never heard of Whitworth thread size, is that a speciality measurement?

It's an old British system, common on cars and other machinery right up until the 1960s. I still have a set of Whitworth wrenches and sockets that my father bought 50+ years ago.


http://www.enginehistory.org/british_fasteners.htm

The derived BA (British Association) sizes were also the standard for smaller nuts and bolts in electrical equipment until displaced by metric.



[This message has been edited by pauluk (edited 09-02-2006).]
Posted By: Alan Belson Re: Metric Inches - 09/02/06 01:30 PM
Whitworth's rifle was a strange beast. In 1853, in a characteristic burst of energy and design flair, he carefully studied the subject and came up with a 44 calibre muzzle loading, hammer and cap, 500 grain bullet, black-powder rifle of immense range, bullet stability, ease of manufacture, accuracy and low weight - with a rifled hexagonal bore!
And he had a state of the art factory in Manchester to build them in. The rifle was baulked at by the War Office, [ because of an inherent black powder fouling problem ] and they ordered a competitor's conventional rifle instead.

The 'Whitworth' was a one-shot marvel, ideal for snipers but not infantry. His rifle swept the board at shooting competitions* though, as one would expect.

[* These contests were a regular feature of Victorian England, with gigantic prize money, akin to a lottery jackpot today. There were no gun laws then and shootists regularly travelled to these contests by train or omnibus with their guns open to view and loaded ].

When his design was rejected, Whitworth bought a building right opposite the War Office and spent many snarling hours glowering angrily across the street through a window at his detractors.

The French adopted his rifle, of course.


Alan
© ECN Electrical Forums