Category Archives: Metric Reform

Drawing a Metric Blank

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Wikipedia Commons

By The Metric Maven

The British documentary series Men of Iron has an interesting overview of engineering in the Victorian era. In the first episode, they discuss the work of Engineer Marc Isambard Brunel (1769-1849). Brunel fled France during the French Revolution and arrived in England. Before Brunel, Engineering mostly involved  the application of muscle to a problem. The documentary states: “A radical new engineering approach was needed. The man who would provide it was Marc Brunel.”

They then note:

Narrator: Marc brought with him a closely guarded Engineering secret from the French Military, something we now take for granted: technical drawing.

Dr Simon Schaffer: “One crucial element in the Brunel system is paper. A world of paper. This draftsman’s skill was an absolutely crucial element in the Brunel system, because it meant you could cheaply try alternatives, where different elements can be combined and recombined, scales can be changed cheaply, and then successfully translated back into the real world.

Engineering drawing and 3D engineering analysis are so ubiquitous today, it’s hard to imagine a time when they did not exist. Indeed it is the paramount importance of engineering drawings, that is often used as a red herring by anti-metric people, to stall change.

When Americans showed up in Panama, the French had been working on a canal from 1881-1889. The US had purchased the French equipment and excavations for $40 million. The French engineering surveys, equipment and such were considered to be worth about $10,000,000. The work had been done in metric, but in this case it was decided that it made the most sense (to the American Engineers) that it all be changed to imperial measurements. I have uncovered one exception where American Engineers and Technicians had no choice but to use metric. This article from the October 6, 1907 San Francisco Call reports on what happened when there was no choice but to use metric drawings:

The endorsement of metric was a bit back handed, with the article seeming to praise the American workers ability to adapt—to a much simpler system of measurement. Given the time, I’m sure Americans would have attempted to convert all the drawings to inches, despite their lauded adaptability, but a time schedule appears to have forced their hand.

The cost of converting to imperial from metric in America is never a budgetary problem—but converting to metric always is.  For example, New Scientist reported on June 22, 2009 that NASA was not going to honor its statement that Orion would be metric. It was claimed that:

The sticking point is that Ares is a shuttle-derived design – it uses solid rocket boosters whose dimensions and technology are based on those currently strapped to either side of the shuttle’s giant liquid fuel tank.

And the shuttle’s 30-year-old specifications, design drawings and software are rooted in pounds and feet rather than newtons and metres.

Hand Drawn Metric Techical Drawing

Let’s see, 30 year old design drawings would place them as having been drawn in about 1979 or so. When I worked in Aerospace,  in the early 1980s, drawings were still done on drawing boards. It was not until around 1987 that I encountered the first project which began to use very primitive CAD software. There was considerable inertia against using Computer Aided Design (CAD), and many drawings were still created by hand. What the NASA administrators apparently are arguing is that they would find it more cost effective to use pen and ink drawings of shuttle solid rockets, than use the nice newfangled software like Solidworks or some other 3D CAD software. Was NASA creating a next generation launch vehicle, or slavishly following 30 year old paper Engineering Drawings with imperial dimensions?

The Engineering Drawings Brunel created in the 19th century, were a great advance, but an even larger one is the development of modern CAD systems. With hand drawings there was never a guarantee of how all the parts, boxes, cables and such will fit. It would be too much work to make complete 3D drawings by hand with all the components integrated. There were always unexpected problems during a build where a device did not quite fit where it was supposed to according to the drawing.

Wile E. Coyote -- Employed by NASA?

Would it not make more sense to design the Constellation vehicle in metric, with CAD, only using the previous hand drawings as guides? Today modern CAD systems utilize “multiphysics” analysis. What this means is that when you draw up a design, one can use now built-in mathematical methods like the Finite Element Method to look at stresses on a structure, see how it changes with heat, analyze the electrical properties for communications and other details which were unthinkable in 1979. In 1987, the first CAD system incorporating my designs had only wire-frame images. What is the cost of bothering with 30 year old shuttle drawings?—rather than using the situation as an opportunity to reform the system and convert to metric.

Newscientist quotes a NASA spokesman:

“The Shuttle and US segments of the ISS were built using the English system of measurements,” says NASA spokesman Grey Hautaluoma.

First, as noted, the Space Shuttle is over three decades old—and now retired. Second, using the International Space Station as an example, is not a particularly good choice for justifying NASA’s decision to continue with its use of barleycorn inches. Notice the quotation states: “US segments of the ISS.” Here is what that means.  In March 2001, Michael Milstein would comment about what happened with metric and the ISS in Air & Space magazine:

“Such lack of backbone may be why the U.S. portion of the International Space Station is built in Imperial Units while the rest of the super-expensive structure has been constructed in metric. About 10 years ago NASA gave serious thought to the idea of building the whole thing in metric, but decided that would drive the cost way up. All the NASA contractors were tooled to build parts in inches and pounds; converting to metric would have required revised designs and new machines. So instead they developed an elaborate and costly computer-modeling and cross-checking procedure to make sure that metric and Imperial parts fit together and work properly.”

“Right now the Russians are controlling the space station, figuring propulsion exclusively in metric units. Once the on-board laboratory (expected to have launched January 18) is up and running, the U.S. will take over control exclusively in Imperial units. When I asked spokesman Kyle Herring of NASA’s Johnson Space Center in Texas what would happen if there were some confusion between the two, if a maneuver supposed to be carried out in pounds of thrust were actually done in kilograms or the other way around, he explained that the station’s propulsion system operates at such low thrust that even a major miscalculation couldn’t send it spiraling into the atmosphere.”

This is not exactly a profile in international cooperation by the US. We’ve discussed NASA and Aerospace enough, how about the commercial sector of the United States?

I worked at one of the last companies to make televisions in the US, along with other consumer products. The one thing I noted over and over was that we almost never went back to any of the old engineering drawings. We were always designing new, and different cases, electronics, and so on. Why on earth would one consider going back and converting any of the old drawings from imperial to metric? It was my good fortune that this debate was never to take place at this company. It had already been changed to metric. This occurred because it was purchased by a European company. They were surprised metric had not been mandated and did so. The company was metric when I arrived.

I then joined a small start-up, designing passive wireless devices, it was all inches and imperial again. Later, when the company was purchased, I was given the choice to use metric or imperial, but could not change during the design cycle. When I started using metric again, I realized that I very, very seldom ever looked at old drawings, I was designing new products. The canard about “do you know how much it would cost to go back and convert all our old drawings?” is just an anemic reactionary excuse without basis. There is never a statement “do you know how much it’s going to cost us not to use metric?”

In the Commercial Engineering sector, changing to metric did not involve any feigned angst ridden indecision. One day I just changed everything to metric. In Aerospace and Defense, the hostility toward metric appears to be a symptom of engineering design ossification. When confronted with metric NASA generates statements laced with metric hysterics (again from Newscientist):

NASA recently calculated that converting the relevant drawings, software and documentation to the “International System” of units (SI) would cost a total of $370 million – almost half the cost of a 2009 shuttle launch, which costs a total of $759 million. “We found the cost of converting to SI would exceed what we can afford,” says Hautaluoma.

Nice quotation marks around “International System” NASA—as if 95% of the population of the planet didn’t use metric, and SI is not international. These cost numbers seem to appear out of thin air, without a single metrication effort undertaken, even on new small projects. What I hear is just a lot of howling, the distressed howling of an agency which has become fossilized and is now asked to change. NASA was the agency which placed men on the moon in less than ten years. NASA agreed in 1988 that it would change over to metric. It simply  insults one’s intelligence to believe that metric conversion is so difficult, it could not be accomplished by NASA in 24 years–and Engineering Drawings are the problem? It’s clear that legislation compelling US industry, education and government to become metric—without an open ended “transition period” is required. If no due date is given for homework, it’s doubtful that a student will ever bother doing it. If the student is allowed to determine their own “transition period” it will become of infinite length.  The US needs a due date, or it will never do it’s homework.. The rest of the world did its homework 30 years ago, while America remains an effete truant.

If you liked this essay and wish to support the work of The Metric Maven, please visit his Patreon Page and contribute. Also purchase his books about the metric system:

The first book is titled: Our Crumbling Invisible Infrastructure. It is a succinct set of essays  that explain why the absence of the metric system in the US is detrimental to our personal heath and our economy. These essays are separately available for free on my website,  but the book has them all in one place in print. The book may be purchased from Amazon here.


The second book is titled The Dimensions of the Cosmos. It takes the metric prefixes from yotta to Yocto and uses each metric prefix to describe a metric world. The book has a considerable number of color images to compliment the prose. It has been receiving good reviews. I think would be a great reference for US science teachers. It has a considerable number of scientific factoids and anecdotes that I believe would be of considerable educational use. It is available from Amazon here.


The third book is not of direct importance to metric education. It is called Death By A Thousand Cuts, A Secret History of the Metric System in The United States. This monograph explains how we have been unable to legally deal with weights and measures in the United States from George Washington, to our current day. This book is also available on Amazon here.

Stealth Imperial in The Kitchen

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By The Metric Maven

Bulldog Edition

Some years back a technician, with whom I worked, gave me a birthday present which I still have. He is a numismatic enthusiast and the present was a cased set of US coins. It has 1 cent, 5 cent, 10 cent, 25 cent, 50 cent and 100 cent coins. Whenever I look at the set, I always think of Sesame Street’s game where they sing a song and ask which of these things is not like the other, which of these things doesn’t belong? Well do you have any idea which of these coins doesn’t belong? Here is the set I was given some years ago:

Now to help you, here are coins used by the EU:

See the one that doesn’t match? Yes, the Euro has a 20 cent coin and not a 25 cent coin. There is no EU equivalent. Why is this? Well most people think that decimalized US currency was adopted with open arms—not so. There were reactionaries that didn’t like this “metric money” stuff and would only allow decimalized currency if it included a 25 cent coin. This compromise allowed the US to become the first country with a decimalized currency. The quarter was insisted upon so the US dollar could be divided in fourths, which corresponds to divisions of the original Spanish dollar which could be divided by up to eight. Hence the jingle: “two bits, four bits, six bits a dollar all for [insert school name here] stand up and holler!” which is repeated at High School Basketball games all over the US each year. Think about what we call the coin. We call it a quarter (1/4) or a twenty five cent piece.. My Grandfather on my mothers side always called a quarter two-bits.

Chances are fairly good that you never noticed this imposition of a non-decimal currency value onto our decimalized money. It’s there, but we just work with it each day, without a clue to its origin, or even taking notice.

When I began metric cooking, I immediately adopted the idea that a teaspoon was 5 mL and a tablespoon was 15 mL. I also used a 1/2 teaspoon or 2.5 mL or a 1/4 teaspoon which is 1.25 mL without giving the measurement spoons much thought. When I began putting together a metric cookbook it slowly sank in, that there were no good “metric equivalents” for the Tsp and Tbl written in recipes. That is, there are no modular values or integer values.  I would see 2 1/2 teaspoons and it would become 12.5 mL. This is true, but doesn’t seem to give you an immediate idea of how many of each measuring spoon one should use. It gradually struck me that what had occurred with my metric cooking was an attempt to “metricate” traditional imperial cooking measures, rather than starting from scratch. And we all know cooking from scratch is also the best way. The volumes of measuring spoons were not chosen in a rational manner using “Preferred Numbers,” (I will have a blog on this in the future) but had been chosen by convention and transmitted by tradition. Because of this, their origins are a mystery, and no one can explain why it was done—they just were. Perhaps three teaspoons in a tablespoon like three barleycorn to an inch?—no, probably too logical.

I quickly realized that to my knowledge, there has never been a set of “metric” measuring spoons created. It was clear to me that this would probably consist of a set of 1 mL 2 mL, 5 mL, 10 mL, 20 mL and 50 mL measuring spoons. This would eliminate the need for a decimal point when using metric measurements. In the case of my 12.5 mL value, I could round up to 13 and use a 1, 2 and 10 mL spoon, or down to 12 and only need 2 and 10 mL spoons. These would be very close to the current measurement values of 1/4 tsp (1.25 mL), 1/2 tsp (2.5 mL), 1 tsp (5.0 mL), and 1 tbl (15 mL) that cooks could convert without too much difficulty. One could also have an optional 100 μL, 200 μL, 500μL set of spoons. Using Naughtin’s Laws one can be certain that the mL and μL would not be easily confused in a recipe. Not even the Australians have metricated their spoon cooking measures. When Australia decided to convert to metric, cooking was exempted. As Kevin Wilkes relates in Metrication in Australia:

Domestic cookery scales were exempted from the prohibition of imperially marked measuring instruments, but the decision by the cookery sector committee to recommend the use of cup and spoon measures meant that most writers of recipes adopted this system, Thus obviating much of the need for metric cooking scales.

***

Spoon measures were unchanged, the existing standard having defined a tablespoon as 20 mL [15 mL in the US] and the teaspoon as 5 mL, but a metric cup of 250 mL was adopted to replace the existing eight fluid ounce measure which was equal to 227 mL

In the conversion of existing recipes, 30 g was adopted as the equivalent of one oz and 30 mL as the equivalent of one fl oz.(tip of the hat to Klystron for providing this information)

Metric cups!  Metric spoons!  Metric ounces! I’ve written about the idea of the use of metric as a modifier for imperial measures. They are ridiculous oxymoron units. I have also written about how the Tsp and Tbl are killers. An Australian teaspoon is 20 mL and in the US it’s 15 mL. The introduction of metric measurement spoons of 1, 2, 5, 10, 20 and 50 mL, would eliminate this disparity and directly use only mL, instead of employing an antiquated proxy unit like teaspoons and tablespoons. It would allow for an international cooking standard to be created.

What truly shows the wasted metrication opportunities and material we will tolerate, and which many people apparently also find entertaining, is a set of “measurement spoons” like these:

click on image to enlarge

One set came “free” with a set of measuring spoons I ordered. The other was a Christmas present I received this year. They are obviously a joke novelty, but the effort was made to manufacture them rather than offering a metric-only 1, 2, 5, 10, 20, 50 mL set of cooking spoons as an alternative. The measuring spoons above are functional, but are never meant for any actual use I suspect, as I do not believe most people commonly use a pinch, tad, smidgeon, nip or dash these days. Nor, I suspect, is there common agreement on each value. I’m sure there are “scads” of definitions. These “units” are good example of unit proliferation. It would be far better to offer a “free” metric set of spoons in place of the novelty ones. I have written about the opportunity for the medical mis-dosage of people because of the teaspoon-tablespoon abbreviation confusion before. If most homes had a “metric set” of measuring spoons, which came with the common imperial ones, people would have the option to directly use mL, even if a dosage cup was not provided on a medicine—or was lost.

During a US metric switch-over, the implementation of a logical set of measuring spoons for cooking, would be a good way to break with the past, and make cooking more accurate and consistent. With metric cooking spoons we could lead the world in metrication instead of bringing up the rear.

If you liked this essay and wish to support the work of The Metric Maven, please visit his Patreon Page and contribute. Also purchase his books about the metric system:

The first book is titled: Our Crumbling Invisible Infrastructure. It is a succinct set of essays  that explain why the absence of the metric system in the US is detrimental to our personal heath and our economy. These essays are separately available for free on my website,  but the book has them all in one place in print. The book may be purchased from Amazon here.


The second book is titled The Dimensions of the Cosmos. It takes the metric prefixes from yotta to Yocto and uses each metric prefix to describe a metric world. The book has a considerable number of color images to compliment the prose. It has been receiving good reviews. I think would be a great reference for US science teachers. It has a considerable number of scientific factoids and anecdotes that I believe would be of considerable educational use. It is available from Amazon here.


The third book is not of direct importance to metric education. It is called Death By A Thousand Cuts, A Secret History of the Metric System in The United States. This monograph explains how we have been unable to legally deal with weights and measures in the United States from George Washington, to our current day. This book is also available on Amazon here.