US Metric System Debated (Engineers Exchange Blows)

Here is a collection of comments in response to an Issue 4 story on metric standards.

GO METRICS - US Should Standardize
from James R. Meyette, CNC Programmer

The metric standard is a standard which should be adopted in the US. I worked for a Japanese Machine Tool builder a few years back and we had a customer that had a certain performance issue (he was programming metric parts in inch mode). We told him to run the machine in metric and it would solve his issue. He balked and asked "What's the difference?", measurement is measurement. Not true we said. "Everything about the machine is Metric" we said. The ballscrews are metric pitch, the control takes inch measurements and converts them internally to metric, makes the move, then converts it back to inch for display purposes. Just another glaring reason the US needs to get on board at full speed ahead with SI units. Besides, it's so much easier to use.

NO METRICS - Conversion to Metric Will Hurt Small Businesses
from Dean Herbst, Agricurltural Equipment Repairs

I would like for us to stay with the US standards and not go to the metric system because it would cost me thousands of dollars. The big thing is in nuts and bolts. Where I have a bolt size 7/16", I do not know for sure how many different nuts and bolts I would have to stock. A #12 is very close to a 7/16". There is a #12 with a 1.00 pitch, 1.25 pitch, 1.50 pitch and 1.75 pitch, and that's just the US standard. In metric sizes, a #12 from Japan will not work with the US standards and a #12 from Italy will not work in place of a Japanese made part, and none of the #12 US parts will work for those ether. I think that any equipment that is imported to the US should be required to be in all US standards.

GO METRICS - Avoiding Metrics is Economically Irrational
from Tim Stephens

I read your Standardization Hindered By Multiple Measurement Systems with great interest. I firmly believe that industry, especially the die and stamping field, must engineer and manufacture in SI units to compete on a global scale. Ten years ago, I was a member of a task force at General Motors to benchmark and publish die engineering standards. It literally took me everyday for six months to convince the team we should be using hard metric. Once convinced, we saved 30% in costs due to global availability of commerical components. Since then, I have consulted several companies on metrication, and have published articles on the topic in my column that appears in a well-read trade magazine. In the global markets today, using any measurement system other than SI is an economically irrational practice governed by emotion.

GO METRICS - European Manufacturers Frustrated With US Resistance
from Bonne A. Rook, The Netherlands

The US are refusing the metric system as "it has not been invented here" (NIH as we call it). They prefer to use imperial standards, as their whole thinking is imperialistic. I am refusing any quotation or supply from US that is not metric. Tell them that they have else to shut up. Europe has already been spoiled with MacDonalds, Coca Cola and Marlborough. Even the good old England is metric now. On the road the signs are still in miles, but the miles are metric. Exactly 1600 meters. As long as the US is not going to be metric, it is for me "Yankee go home."

NO METRICS - And Speak Chinese Too?
from Steve Woolley, Formulation Chemist

While it may be easier to adopt only one system, in the era of inclusion and acceptance, why can we not be bi-lingual engineers? Does Mr Schweisthal also suggest that we all learn to speak and write Chinese sinces there are more Chinese people in the world than any other nationality?

NEUTRAL - Metric Values Vary
from Fred Saalbach

The metric system as practiced is really not any better then the US system in terms of consistency. Many nations put their own flavor on things. We could actually argue that the US is already on the metric system as in the late 1950's the US units were redefined in terms of the metric units.

Your issue is really having parts that are interchangeable with metric parts. But which metric parts JIS, ISO, EN, GOST or whatever? In many product classes there is a mixture of hard conversion and soft conversion parts. Hard conversion is a part that was redesigned so that the physical dimensions of the part conform with the ISO guidelines on selecting dimensions. Soft conversion might only indicate that the English dimensions are expressed in their metric equivalent. This is often an installed base issue. Do you really want the hardware store to stock 70mm pipe and then find you need to connect it to the 3 in sanitary drain in your house.

GO METRICS - Do The Math
from Dr. Michael Graefe, Germany

I am happy to read your opinion about the metric system. I find it so much easier to use. I always amuse American engineers by

        1 N*m  = 1 J = 1 W*s

NEUTRAL - Metric Values Vary (What is the standard?)
from John T. Albers, Senior Project Engineer

To say every other nation is playing by the same rules as long as they have adopted the "metric system" is very misleading. There might be considerable conformity between nations on the subject of electrical engineering. However there are no less than 5 standards for hose and tube fittings (SAE, JIS, DIN, British, NPT, ISO, etc.). Have you ever looked up the section modulus of a typical wide flange shape in metric units? Inches to the third power convert to some exponential number in millimeters. And how about pressure? The US standard is pounds force per square inch, whereas some nations use newtons (force) per meter squared, others kilograms (mass) per millimeter squared. Which units should we adopt?

While I was in college my text books typically would have problems that involved both SI units and "Imperial" units. The thing that struck me was that it was much easier to comprehend the magnitude of the "imperial" units than SI. Perhaps it was from my upbringing in the U.S. By the way, the "metric system" originated during the French Revolution as a reaction to "imperial" units. A ten day week was also proposed since the notion of a seven day week is based on the Bible.

GO METRICS: Blam! Crack! Pow!
from Ian Hook

Bloody Americans, give them an inch and they standardise on a mile!

NEUTRAL - US Engineers Already Use Metrics
from Jim Brown, Design Engineer

I think Mr. Schweisthal has misrepresented a great number of young engineers coming up today. During my college years English units were typically an afterthought. Most exams and homework featured problems solved in metric units. The fact is many younger engineers work almost exclusively in the metric system because we've grown up (academically) with it.

In my brief career (I have been out of college only 3 1/2 years) I have worked with or for Cummins, Case (prior to the New Holland merger), John Deere and Hitachi and can count on one hand the number of English unit prints I've used or drawn.... Working in the manufacturing of diesel engines and the design of hydraulic excavators, I can say that my brain thinks metric first. I'd much rather deal with decimal millimeters than fractional inches. I use English units only in terms of putting gas in my car, driving to work, lifting weights at the gym and woodworking hobbies. Even working on my car requires metric tools and measuring devices lest I would spend my Saturdays trying to figure out why my 89mm cylinder bores aren't exactly 3.5 inches in diameter...and what fun would that be.

GO METRICS - Not Adopting is Lliving in the Past
from Niel J.P.Fagan, Lab. and Process Superintendent, England

John P. Schweisthal hit that nail squarely on the head, but in England we have it even worse with Metric, English Imperial and american english to contend with.

We buy units from Asia and its metric, from Europe metric again, from USA a horrible mixture some (few) metric but mainly weird sizes that make little sense like #8/32 threads. Yes we still have some older kit with BSF/BSW, but atleast they make some sense and you can still get most sizes of nuts and bolts off the shelf, unlike most US threads.

Yes we English have gone metric, for MOST things, and its much much easier to build systems as a result, we still retain BSP (our imperial pipe thread standard) which has been adopted by most of the rest of the world and it now has an ISO designation too.

We understand that the USA likes to do things differently, BUT using non-standard thread systems and the measurement systems that go with them (or is that the other way round) is just living in the past, as with most industries here its modernize or die, or atleast get stuck in an unfavourable trading position time-warp.

I was trained when inches were king, moved through the transition, and apart from historic equipment (and vehicles, a 1950's Land- Rover being my preferred mode of transport, for ecological reasons as much as anything else) most everything is now metric, and fits first time without wasteful and sometime dangerous adaptors made by unskilled workers "just to make it fit", re-building is an off the shelf prospect with standard parts and no problems with odd threads etc.

Move on, don't live in the past, the future is out there, grasp it with both hands, sure it'll hurt for a while, but change always does, and go for it, the old'uns will complain, but working in metric is easier, base 10 calc is quicker, and in 15-20 years you may have even have caught-up with the rest of the world!

How did you get started?

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1. When did you realize that you were headed for a career in your chosen field and how did you know?

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Thanks,
Jaren Green, Editor
jaren.green@ihs.com
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