Assembly Blog

Hoffmann on Testing: Why Are We Still Dragging our Feet on the Metric System?

May 2, 2011
/ Print / Reprints /
/ Text Size+

What’s one thing we have in common with the great nations of Liberia and Burma? We are all clinging to the English imperial system of measurements. Really! And while we are no doubt proud to stand with them in the distinct minority of nations insisting on the English system, does it make sense in the 21st century global economy? Of course not!

Here’s another head-scratcher. Who was the first nation to sign the Treaty of the Meter in Paris in 1875? Give up? The US of A! We signed, but we didn’t convert. So, after 100 years of foot-dragging, Congress passed the Metric Conversion Act in 1975. And this year we can celebrate 36 years of additional temporizing.

Of course, the global customers of InterTech know we manufacture our leak testing systems to either or both metric and English standards, as required. This results in unnecessary additional costs.

Case in point: Many U.S. vendors do not have complete metric versions of their products, which means that often we will be required to use foreign-made components. Because they are imported, these parts are therefore more expensive and harder to get.

Often, leak test specs will use mixed units, such as X sccm (standard cubic centimeters per minute) at Y psi value. This is inconsistent, leading to errors in globalized operations. To avoid conversion errors, SI units should be used.

As engineers I’m sure we can all agree that switching to metric is the right thing to do-sooner rather than later.

Jacques Hoffmann is president of InterTech Development Co., which designs and builds equipment for leak testing, functional testing and test-centric automated assembly. He can be reached at 847-679-3377.

Editor’s note: “Hoffman on Testing” is part of a series of guest spots by industry experts that will appear regularly on ASSEMBLY’s blog page. Check back frequently to read more commentaries from Jacques, as well as contributions on automated assembly systems, electronics assembly, machine vision, robotics and ergonomics.
You must login or register in order to post a comment.

Give 'em 2.5 cm, and they'll take 1.6 km

May 2, 2011
Mr. Hoffman is quite right.  Still, I can't imagine Walter Payton running for 91.44 meters against the Packers. Some of ASSEMBLY's older readers might remember Machine Design magazine's first and only pin-up: Miss Metric.

liters vs. gallons

May 6, 2011
It would sure bring gas prices down in a hurry.

--Reed Smedberg, manufacturing engineer, Fort Wayne, IN

metric better for our economy

May 25, 2011
In 1976, I was ready for the change to metric and then it never happened because some industries lobbied and said it would hurt our competitiveness. We'll we've lost our competitiveness now and a conversion to metric would actually help us compete in the world market.

a better solution

May 25, 2011
The world should convert to the English imperial system.

but what of school exams

Jim L.
May 25, 2011
Now what fun would it be to take an engineering exam that was already all in SI units and the answer needs to be also in SI units? The exam time would have to be cut in half!

Metric is more expensive to manufacture.

May 25, 2011
The metric system is perfect if you work only one the left side of the decimal point. But being a machinist I know all too well that when working in thousandths of an inch the metric equivelants become increasiningly less acurate or require significantly more measurning tools to accomplish the same task. It has to do with the scales and the jump from .01mm to .001mm is unrealistic to tolerance and manufacture specs and cost suffer due to this. Having worked with both systems I know first hand what seems easier to an engineer is usually more difficult in practice.

Lots of guys still think in "thou's"

July 12, 2011
In the olden days-the 1970s-when I was a spotty teenage apprentice at Rolls Royce Aero engines, they told us that metric was the future and we should learn the imperial system, but it would be gone in 10 years. I still know lots of guys in the UK who think think in “thou’s.” We have now pretty much switched over, but we fill our cars with litres of petrol and drive at miles per that one out?

I suspect the US reluctance to change is historical and people wanting to hang on to the good old days. Perhaps they just dont like those Europeans telling them what to do!

And whoever came up with counting to 12, 14, 16, etc.? We only have 10 digits on our hands!

-Steve Tatem, director, Tatem Industrial Automation Ltd., Derby, United Kingdom

Metrification will make US more competitive

July 13, 2011
The metrification process in the US industry has always intrigued me and frustrated me at the same time.

I have a very strong and long background in the automation industry, which is, in reality, systems integration of as many commercial components as possible, and my frustration comes from the lack of availability of metric components in the United States to meet a customer’s all-metric specification.

We import alternate components to meet this metric requirement, which comes at a higher price, lead time and logistic effort….often to export the now integrated component back to its birthplace.

I am intrigued by the industry’s lack of interest in self-regulation to finally convert its products and specifications to hard metric standards. Somehow, there is still a wait-and-see attitude. Meanwhile, those suppliers with hard metric components take the business away from those that actually invented the automation industry in the first place.

Metrification of existing and future products is not that difficult and very necessary in order to support and make more competitive U.S. automation system developers, now shipping product worldwide.

-Val Taruntaev, president, Prime Research LLC, Gilbert, AZ

Just get it done

July 13, 2011
I know that the United States has had legislation on the books since the 1970s requiring government departments to change over to SI, but the key to the failure is in the “out clause” that allows departments to choose not to change if there would be significant financial or other hardship in their sector due to the change.

I live in Canada and was in the generation that was in primary school in the 1970s. This was the time when Canada was changing over from Imperial to SI, and we were taught both systems. I still think in either system, depending on what I’m doing, but I prefer SI for most things. The kids that followed my generation through school only learned SI, and they are often lost when they run into Imperial.

Working in industry since 1985, I have been very surprised by the amount of Imperial hardware and Imperial design still done. It was mostly products that were destined for the EU that were designed and built in “full SI.” Like Steve said, I think it’s partly just a comfort-zone thing.

It’s like anything else I think-just tear the bandage off and get it done. Sure it will hurt for a minute, but then things will go back to normal. Just a new normal. One that counts by 10s!

-Doug Nix, A.Sc.T., vice president for conferences, IEEE Product Safety Engineering Society, Kitchener, ON

CNC machine tools make converting easier

July 14, 2011
In the past, the main reason for not implementing the metric system has been the prohibitive cost of changing out our machine tools. Now that most machine tools are CNC, that argument doesn’t hold water. As a machine designer working for a company that has both U.S. and Chinese manufacturing facilities, I would like to see us move towards the SI system. I’m constantly asking myself, or others, where are we going to be making the parts I’m designing. Usually, the answer is that it could be either place, depending upon cost and end user location.

-Randy McAloon, mechanical engineer, Faustel Inc., Milwaukee

Let's hear it for the Sumerians!

July 14, 2011
Reply to Steve Tatem.

The Sumerians came up the numbering system, and it’s really quite elegant. It’s sexagesimal ( i.e. 60-based). Why? Because 60 is a highly composite number and has 12 factors. (1,2,3,4,5,6,10,12,15,20,30,60). 100 only has 9 factors (1,2,4,5,10,20,25,50,100). Why is this important?

It makes numbers easy to divide into different ratios when you don’t have a calculator. Suppose we had a metric clock and you had to be somewhere in exactly 20 minutes. That would be 33.33333 minutes in metric time. Ugggh!

-Gary Niklas, program manager for automotive and manufacturing, Promation Engineering Ltd., Toronto

It's hard to visualize metric units

July 14, 2011
The problem is both internal through visualization, and external via marketing perception.

Can you visualize 5,280 feet? Probably not. It’s much easier to call this, 1 mile. The human brain can assimilate with a degree of accuracy, numbers in the range of 1 to 50. The problem with the metric system is the unit base has no visual reference equivalent. (An inch is knuckle to tip of finger, a foot is , well, a foot, a yard is roughly an arm length. These are visual measurment guides everyone carries with them.)

Another problem is that the increments between the unit sets are too large, so for the linear measurement of everyday items, you end up with numbers that are too small or too large to visualize.

For example, a standard sheet of paper is approximately 215 x 280 millimeters (designers working in this range typically use millimeters). For English, this is 8.5 x 11 inches, which seems easier to visually categorize to memory. At the opposite end of the spectrum, the size of a typical residential room is 10 feet x 12 feet. Real estate listings would show this as 3.05 x 3.66 meters. (Canada is required to list these in meters). The numbers are too small in variance to accurately visualize. This is probably why rooms were measured in feet as opposed to yards in the English system. (A yard being very close to a meter in length.)

The external influence on perception is another factor. In Canada, gasoline is sold in liters. This was a no-brainer for government to institute since $0.40 per liter looked a lot better than $1.20 per gallon. Government and oil companies could both hike up their “share” on converting the masses. (That is probably why Canadian gas prices are consistently higher than prices across the border.)

Grocery prices in Canada are altogether another matter. Produce must be legally sold in metric units. However, the advertised price in large print is typically in English units, since $1.99 per pound looks a lot cheaper than $4.38 per kilogram. Metric is typically priced in “fine print.” All the scales were only in metric, so this was a real boondoggle for awhile until metric scales (with English conversions) were allowed due to resistance on that front. Oddly enough, meat counter scales had to remain metric “being legal for trade,” so everyone knows what 250 grams of turkey amounts to.

Due to our cultural diversity and the fact that most of us have had to learn both systems, we Canadians pick and choose units depending on application or situation, just like having a second language. Problem is, with the global community, things can get lost in translation and maybe this is why the United States sticks to the system they know, locally.

“This is Mars Lander control, was that 300 miles or 300 kilometers?? Ohhh crap!!”

-Gary Niklas, program manager for automotive and manufacturing, Promation Engineering Ltd., Toronto

we need a universally understood language

July 14, 2011
If we choose the measurement system to best suit our egos, we could use stones for weight, feet for height, centimeters for the fish we catch, and if we have small hands, we would have the tallest horse in town…

The whole point about going metric is that there will no longer be a senseless need to convert back and forth. It will an element of an universally understood language, which we already have for time, angles, mathematics, musical notes, and other variables.

-Val Taruntaev

It might only take some power players

July 19, 2011
I think a lot of it is cost in America. If I want a fastener, outside of unusual sizes, imperial is always cheaper. I can get someone to make me a part with metric dimensions, but I know it will take longer and cost more because American machinists will have to take the time to convert to imperial and back when machining and measuring. Machinists hardly ever have the same array of metric tooling as they do imperial.

However, given our “trendy” culture, it might only take some power players (or a consortium of big players, like the Big Three, some computer giants, etc.) to just state that they are going all metric. Making metric popular might give it the momentum it needs.

-Tom Wiesen, senior manufacturing engineer, Viridian Green Lasers, Minneapolis

Metrification of USA

Brad Mountz
July 19, 2011
Football and sign posts aside, bringing metric to manufacturing is NOT more expensive in the long run. Metric fasteners commands a higher price because they are still considered somewhat "special" and they command a higher price because of it. Standardize and cost goes down. Today, a fastener distributor, of which I'm one, has to stock double the product to serve a market that is mixed use. But my cost on a 6mm screw vs a 1/4" screw is no different from the actual factory. In fact, because Metric is used the world over - it is less. I'm not sure everyone would agree, but to meet it seems easier to measure in 1, 10, 100, & 1000 than it does in a decimal based system that is expressed in fractions. For me the benefits are: stock more of what my customers need, sell them a more competitive price, reduce my labeling, handling and SKU costs. I have to think it works that way for the entire supply chain?

NO! to Metrification in USA

Craig Fenske
September 29, 2011
I won't convert until those metric socialists show a viable metric system for the 4th dimension - time. we remember there are 7 days in a week and 60 seconds in a minute and 365 days (or 12 months) in a year, but remembering 12 inches in a foot is too hard? where are tomorrow's children going to learn fractions if they grow up learning the metric system?

What's the big deal?

November 14, 2011
I must admit that I am a bit curious and surprised about all the wailing on this subject. While the arguments regarding how the metric ball started rolling might be interesting, it is not difficult to make necessary conversions nor "get a metric sense" for physical quantities. All the current CAD packages speak both languages so conversion is a non-issue. Most every gauge available has both scales on it. I'm an "old dog" but picking this "new trick" was rather trivial for me. Is this issue just a matter of US pride or is there some technical or cost justification behind our reluctance to adopt the metric system? What am I missing?

-Ron Scicluna, director, PPI Consulting



Image Galleries

Behind the Scenes at Ford's Michigan Assembly Plant

People are the heart and soul of the 2012 Assembly Plant of the Year. This slideshow shows some of the men and women who build three different types of electrified vehicles alongside traditional gas-powered cars on the auto industry’s most flexible assembly line—Ford’s Michigan Assembly Plant in Wayne, MI. Photos courtesy Ford Motor Co.


Live from The Assembly Show, the hosts of Manufacturing Revival Radio sit down with Adam Malofsky, Ph.D., president and CEO of Bioformix to discuss his company’s innovative, energy-saving adhesives and polymers, which cure without the need for heat or light. 

More Podcasts


Assembly Magazine

april assembly cover

2014 April

The 2014 April Assembly includes a cover story about robots and small manufacturers plus much more. Check it out today!
Table Of Contents Subscribe

Immigration Reform

Could immigration reform benefit U.S. manufacturers?
View Results Poll Archive


Welding: Principles & Practices

This text introduces students to a solid background in the basic principles and practices of welding.

More Products

Clear Seas Research

Clear Seas ResearchWith access to over one million professionals and more than 60 industry-specific publications,Clear Seas Research offers relevant insights from those who know your industry best. Let us customize a market research solution that exceeds your marketing goals.

Assembly Showrooms

ASSEMBLY Showrooms


facebook_40px twitter_40px  youtube_40pxlinkedin_40px