Category Archives: Metric Education

The Invisible Metric Embargo

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By The Metric Maven

Bulldog Edition

About four to five years ago I’d had it with imperial measures. I decided I was going to set my engineering lab up with nothing but metric. The first purchase I made was a dial caliper. I next wanted to purchase an honest to goodness meter stick, with only metric markings and not dual scale with inches. I went to the local metric supply store, and they were puzzled that I wanted a meter stick with nothing but  a metric scale.

Where could I get a meter stick? Well, our friends in the Great White North are metric—right? I trolled websites looking for high quality meter sticks. All I could find were painted wooden ones with centimeter markings. I purchased a pair and waited for them to arrive. It bothered me I could not find metal ones.

For six months to a year, I muddled through using small metal rulers with dual scales, all centimeter with millimeters between. I had converted my software and other computer aids to metric. It was then I first heard some of Pat Naughtin’s lectures, which were eye-opening for an American.

I fumed at the lack of metric availability in the US, and wrote an editorial which was published in a local paper. Pat Naughtin and Mike Joy, both from Australia, commented on how pleased they were I had spoken out. Mike contacted me by email and wanted to know if there was anything he could do to help. I told him I had one hell of a time finding metric only rulers in the US. Mike generously said he would send me some. I insisted I pay him, but he was more than pleased to send them along without prior payment.

When they arrived I had a 150 mm, 300 mm, and 600 mm set of beautiful steel metric only rulers. I was just dumbfounded. I’d never seen such things. They were easy to read, simple and elegant compared with imperial and the Canadian meter sticks. When I began using them I was in for a second revelation. All engineering drawings I’ve ever seen are in millimeters. When I was using my milling machine to create parts, suddenly it was much, much easier to read the measured dimensions of prototype PCBs. I pondered, and then realized I had been converting centimeters to millimeters in my head, because the Canadian meterstick was in centimeters. I had been doing an unconscious conversion without realizing it, constantly moving decimal points in my head.  Once I no longer did this, I noticed the ease of checking dimensions on machined PCBs, but it took me a while to realize why.   That was when it dawned on me that centimeters were indeed a bad idea.

Australian 300 mm Metal Ruler

Mike was very eager to help me obtain real metric-only tools from Australia. He also had an eye for quality tools. I was able to purchase a mm square, and a machinists combination square. To my surprise I was able to get a metric radius gauge, by mail order, here in the US.

The most interesting tool Mike was able to provide, was a true metric socket set. One of my complaints is that all the metric sockets in the US are just American sockets, kludged with metric ends. What I mean by this is the drives for various sockets are 1/4″ , 1/2″ and 3/4″ with metric on the other. My father has complained to me on numerous occasions about finding the right adapters to go between these different size drives. I was lectured several times by multiple people that Americans invented the socket wrench, and our drives were the international standards, so even if they gave the drives metric dimensions, they were actually in inches. I could almost hear a fife and snare drum in the background as they talked—like a speech given by Oliver Wendall Douglas..

When the metric socket set arrived from Australia I was was again dumbfounded. Once again my fellow Americans were talking out of their posterior. They just assumed what the rest of the world was all about. I had proof their viewpoint was so much intellectual vaporware. Below is a photograph of my metric socket set. It has a 19mm drive, with adapters for the old fashioned 1/4″ and 3/8″ imperial socket sets. A short 80 mm extension is included. It is a Tradesure Part No. TS4019.

Australian Metric Socket Set

It was at this point I began to realize, I lived in a country that has an informal, invisible, and strict metric embargo in place. The rest of the world enjoys the use of metric only tools, but they are never imported or sold in this country. If Mike Joy had not volunteered to help me break this metric embargo, I would have not been able to outfit my Engineering Lab  with all metric, millimeter based tools.

Mike made a trip to the US and stopped to pay me a visit. He brought a set of metric drill bits from Australia, and showed me a millimeter metric tape measure from Australia. Mike was willing to give up the drill bits, but he’d promised the metric only tape measure to another friend he was visiting. I wanted a millimeter only metric tape measure, and hoped Mike would send one once he was back home.

Unfortunately, incidents in Mike’s life prevented him from helping me further. I was now on my own, I had to do my best to break the invisible metric embargo. When I first began to purge my lab of imperial tools, I had purchased a metric-only tape measure, but it is “US designed” and has centimeters and millimeters. I was completely over using centimeters. I put the old centimeter tape measure in a beat-up old tool box, far away in the back of my garage, with my imperial tools. I looked and looked online. One American manufacturer had a millimeter based metric tape measure in their catalog, but when I called them, it was “discontinued.”

One day my luck changed, I found a boat-building supplier that had metric tape measures, they were all centimeters, except for a small one that was millimeter based. I was willing to take what I could get at this point. I purchased two. They were better than not having one at all. The boat building supplier then stopped offering metric tape measures. I wanted a larger, easier to read, mm tape measure. I found a supplier in Australia called Bolts & Industrial Supplies. I could get metric only tape measures from them I was told, but the shipping would be very expensive—and it was. I was also able to cross-reference Mike’s set of rulers and get extras, along with a true stainless steel, millimeter graduated, meter stick.

Tape measures in mm only — Good luck finding one in the US (click to enlarge)

I thought I was through purchasing tools for my lab, but I then realized why my metric calipers had been so hard to read. The dial was millimeters and the slide was centimeters. I had been converting the value on the slide from centimeters to millimeters, and then adding the millimeter reading from the dial. An American distributor had sold it to me. I finally located a millimeter based set of dial calipers, and the mixed set were banished.

Over and over I’m told, “hey, this is America, you can choose to do metric if you want, nobody’s stopping you.” That is a load of bull. There is no choice of quality metric tools in this country. But there is often a choice of inferior ones. I receive catalogs for machinist tools periodically, and they are all imperial sized. They offer endmills that are 1/4″ or 1/2″ or 3/8.”  No metric listed, no metric offered, no choice in America.

Millimeter Combination Square

Ninety five percent of the worlds population uses metric, and we try to put our hands over our ears, close our eyes, and ignore them. The absence of quality metric-only mm based tools in the US demonstrates this truth most effectively. It is proof of an invisible metric embargo. The lack of metric in our economy makes it far less competitive than it could be. The European Union has a larger economy than the United States. China is projected to have a larger economy than us by around 2016. A metric switchover would be a sound investment in our future, stimulate our economy, and make it more competitive. We could rebuild our bridges and infrastructure more cost efficiently in metric, and get more for our tax dollars. This would allow US workers to experience metric only building, which would in turn help us to competitively bid on metric building construction overseas. But I guess these are not priorities in Congress, or among the American public, but they should be.

Updated 2017-08-14

Related Essay:

The “Preferred” Measurement System of the US

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.

Making The Milligrade

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By The Metric Maven

Bulldog Edition (Extra)

I have to admit that there is only one measurement identified with the metric system that gives me pause.  It’s temperature. Most of the world uses Celsius, and seems fine with it. US detractors surround me, and with boney fingers, point out with derision how compressed the Celsius scale is when compared with Fahrenheit. I object, and defend Celsius, but my heart is not exactly in tune with my defense. Fahrenheit has almost twice the number of graduations over the same temperature interval as does Celsius. My mind wants to embrace Celsius, but pines for some undefined metric mistress of temperature, with whom it would prefer to spend its time.

About a year ago, I started trying to expose myself to mostly Celsius thermometers to see how familiar and comfortable I could become with the scale. In the Winter I find it rather informative to have zero at the freezing point of water. Most of the meteorologists in the US may not say zero degrees Celsius, but almost always describe the number of days above or below freezing. The freezing point is of course assumed to be that of water. I put a Weatherbug on my computer desktop set for Celsius only, and Mike Joy was kind enough to send me an outdoor thermometer from Australia in Celsius only. I really like the way the temperature ranges for human comfort are designated with colors. I mounted the Celsius only thermometer just outside my back door. Below is an image of this thermometer:

Australian Metric Only Thermometer – Click to Enlarge

I’ve slowly become accustomed to temperature in Celsius, and if there was a total switchover to SI, I would be comfortable in a fairly short time I suspect. I seem able to keep C and F separate in my mind. All I would have to do now is drop the F from my world.

An Engineer from the UK, with whom I had worked in the past, visited with his fiancee in December sometime back. It was with pride I pointed out the thermometer Mike had sent me, and in return I received an impish smile. My British friend informed me that his soon-to-be wife could only think in terms of Celsius in Winter and Fahrenheit in Summer. This information hit my mind with the same reaction a cat might have as a stream of water unexpectedly impacts its face. I looked at her in astonishment, with my countenance frozen and contorted. Words failed me. All I could say was: “Really?” I decided this was a very, very unusual data point, and pushed it to the back of my mind—until recently. It resurfaced when Deputy Prime Minister, Lord Howe called for the UK to finish the metrication it had started years ago, but had been halted by the Thatcher Government around 1980. I was amazed in this time of deafening silence about the metric system in the US, that any politician, anywhere would mention it. I read comments by the UK Metric Association members, and one suddenly jumped out. Because the UK made it about half-way in its metrication effort, the weather reports could be in metric or imperial. The British Tabloids, who are not noted for their calm, objective approach to the news, often report Summer temperatures in Fahrenheit and Winter temperatures in Celsius. Thankfully, the UK people explained why. The Fahrenheit temperatures sound really large and give the impression of exaggerated high heat in the Summer. Great copy! The earth’s crust is in danger of melting!  In the Winter, because 0 C starts at 32 F, Celsius exaggerates how how cold Winter temperatures are. Fimbulwinter is upon us! Ragnarök cannot be far behind! Repent!

Ray Bradbury’s Celsius 451 or Milligrade 4510

This is a somewhat, benign example of what happened before worldwide adoption of the metric system. One could use multiple measurement units to fool customers (marks?) into making purchases that favor the merchant when he sells, and also when he buys. The option of a choice between two similar sets of units can easily lead to confusion. For instance, perhaps the most famous novel in the English language with temperature in its title, is Ray Bradbury’s Fahrenheit 451. This is the temperature at which paper spontaneously bursts into flame—except it doesn’t. The actual temperature from the technical literature of the time is Celsius 451. Yes, the person who decided upon the title of this book made a Celsius/Fahrenheit mix-up.

If one is old enough, they may recall when Celsius was called Centigrade. The idea was that the temperature from the freezing point (triple point) of water to the boiling point would be divided into 100 parts. Zero Centigrade is the freezing point, and 100 Centigrade is the boiling point of water. If we follow the reasoning of the metric prefixing scheme, it would imply that this scale is obtained by dividing up a temperature interval called the “grade” into 100 parts. The grade would be a normalized range from 0 to 1, which makes a lot of sense.

It has been argued many times on this blog, that the “prefix cluster around unity” is a cluster. Naughtin’s Laws explicitly eschew centi-anything, and use milli instead. After much thought, I believe that the common temperature range which should have been used instead of Celsius, would be the milligrade scale. It would be from 0 to 1000. Like the use of millimeters for Australian building construction, decimal points would never be needed. Only Engineers and scientists might ever need temperatures with a precision smaller than those given by the milligrade scale. There would be no confusing Fahrenheit and Milligrade values. When it’s 100 degrees F, then it’s 378 milligrade—take that British Tabloids! If the reference book Ray Bradbury’s publisher consulted to find the self-ignition temperature of paper had been in Milligrade, there would be no confusing a temperature of 4150 with Fahrenheit or Celsius.  My fellow Engineer Lapin has told me that much of the temperature data on the web, which is meant for professionals, has the temperature in Celsius generally given to a tenth of a degree. All we need to do is move the decimal point, invoke Naughtin’s Laws and presto, a much more usable integer temperature scale for humans exists without decimal points.

If one is a strict adherent to SI definitions, then the actual temperature standard is in Kelvin. Celsius is a derived scale.  The definition of zero Milligrade or Celsius was the triple point of water. It turns out that if you have ice, water and water vapor all present in a sealed triple point of water cell, and then wait for a while, the temperature will stabilize at a very precise value (0.01 C or 0.1 milligrade), which may then be used as a standard. It is called the triple point because you have all three states of matter: liquid, solid, and gas present, and in temperature equilibrium. Celsius is actually derived from the Kelvin scale and the two points of definition are absolute zero and the triple point of water, so the 100 degree boiling point of water is no longer part of the temperature definition.

Farhenheit in a Centegrade World — Click to Enlarge

But imagine the plight of poor Fahrenheit, it is only derived from Kelvin by way of Celsius. When you are a Metric Maven in the United States, you know what it feels like to be Fahrenheit in a Centigrade World, but my new metric temperature mistress, milligrade, would fix that problem for temperature, and provide much needed comfort to my psyche.

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.