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# To metric or not to metric? Is that (still) the question?

Recently, in response to an article headline that included our good ol’ Fahrenheit temperature unit, a reader took us to task for not using the international Celsius standard.

That sparked a conversation about the U.S.’s continued use of the imperial system of measurement, both in the wider culture but especially in the design engineering world.

So what do you, our Engineering Exchange members, think? Is it worth it to revisit the subject of using only metric units, or do we continue to accommodate both metric and imperial units?

And what about the wider culture? Do we start with teaching our children only the metric system from a very early age and let them lead the way? Do we begin to calculate kilometers per liter instead of mpg?

Tell us what you think.

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Comment by Roger Fentiman on June 14, 2011 at 4:06am

As a sufficiently antique engineer working in the UK, I've worked through the imperial - metric switch; in fact two metric systems because I was taught in centimetres-grams-seconds at school, then found myself in a metre-kilogram-second world. It was a cinch; I now happily do all my engineering in millimetres, kilograms and newtons. (A newton? about the weight of an apple...)

OK, I'm tainted in certain ways; I cook in ounces and grams, drink in pints and ml, drive in miles and litres, do my carpentry in a mixture of inches and metres according to how big a measurement it is; but I get by OK. Because my engineering is ENTIRELY metric I haven't had any equivalents of hitting Mars too hard yet.

Comment by Roger Curl on June 14, 2011 at 1:56am

We here in New Zealand went Metric in the 70s after the successful currency decimalisation in 67. A certain time after its introduction, it was compulsory to sell in only metric units. Drawings started to be produced in metric. People adapted quickly and now the young ones struggle to get their heads around the inperial stuff. There was a period in our toolroom when machine tools were still imperial and we had to do a lot of conversions. We would cut off a piece of 2"x½" steel bar at 300mm long. It wasn't a problem, just used a dual scaled rule. A lot of people still refer to a 3ft surf at the beach or a length of 4x2, but it's all marketed in metric. Long term, it's the best thing we ever did. We deal with a lot of international industries where the standard is metric. Would I ever go back? Never! The small amount of inconvenience was well worth it. Calculations are far simpler. It does take a while to get your head around the different units, but if you accept the change and get on with it, it soon becomes familiar.

Roger

Comment by Nick Green on June 14, 2011 at 1:54am

Roger,

Might I ask this question then, where do I get a bunch of pounds force to hang on the end of a bar? They no more exist as a physical entity than Newtons.

Is the difference between mass and force really so difficult and 'uber-educated' ?

Personally being an engineer in the UK and working primarily in metric I find the American or Imperial need to label mass and force with the same unit irritating but not exactly worth getting upset about. I do wish people would spell the units correctly though - it is a litre not a liter!

I work in metric but I still drive miles and drink pints (proper English pint not the little US one!), it isn't important what you measure things in, so long as everyone knows what the units are.

Comment by Neil on June 14, 2011 at 1:29am

When South Africa went metric back in the seventies they made it illegal to manufacture or import imperial measuring devices and only taught metric in schools. It worked.

In England the metric change was taught in the seventies but now they are re-introducing imperial so that students will be able to understand Americans.

If America sticks to their guns (sorry that's another subject) the whole world may follow :-)

Comment by Bjørn Breitzke on June 13, 2011 at 11:40pm
Since Engineering Exchange is supposed to be a global community the answer is easy: Metric. The US is the only country left still using imperial and even the English inventors have abandoned it. Did you know, the USA was one of the first countries after France to implement the metric system in its legislation? I fully understand the inner resistance Americans must feel when they hear kilometers per liter, its exactly the same when i hear miles per gallon or btu / hr ft F. So the best thing would probably be to use the dual system.
Comment by OSCAR LANCHEROS on June 13, 2011 at 8:14pm
we have to be able to handle any system...
Comment by Roger Davies on June 13, 2011 at 7:29pm

Brian:

This is the same blather I get from the uber-educated. You don't seem to get past your education and come down to where real people live. I understand that you are TECHNICALLY correct.

I ask again, where do I get a bunch of newtons to hang on the end of the bar?

Comment by Forrest Higgs on June 13, 2011 at 5:27pm

Just for the record, the US does not use "Imperial" measurements.  American and "Imperial" measurements overlap in places and are radically different in others.

Comment by Ross Huber on June 13, 2011 at 4:38pm
Just went down to the quality department at work........gauge blocks, precision pins, calipers, height gauges, v-blocks, on and on, all certified.  Not a metric tool in sight.  Just happened to be reviewing a military SOW...all units in Imperial.  I sent a cut file to a laser cutting company and they told me they couldnt cut a 140 ft file, it was in millimeters.  Get over it people.  We are not switching to metric.  Dual units is all we can hope for, and if you think otherwise, you can pay for it.
Comment by Ronald A. Fossum on June 13, 2011 at 3:55pm
Dana, I too live in the PacNW (Portland), but the main reason that manufacturers or suppliers (like Home Depot) switch over is very simple (using your example): 1/2" plywood is 12.7mm, but this will not do and 13mm is 0,51181". No self respecting plywood mill (or any other manufacturer) is going to miss the chance to make more profit by decreasing the amount of material - but to stay fair with SI one needs to use whole numbers. Therefore 12mm, which equates to 0.47244" or 15/32"+ (multiply the 0.47244" by 32) and "justifies" rounding  to the nearest 32nd of an inch. We have 15/32" plywood which is 1/32" less than the previous 1/2" or 1/16 savings in materials. The savings over the billions of sheets of plywood annually produced in the USA is enormous.