Category Archives: Metrication

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.

Feral Units Endanger Our Health

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By The Metric Maven

Last year, I spent one beautiful afternoon driving back roads through the Rocky Mountains with my friend Thern, who is a Mechanical Engineer.
I don’t recall the conversation exactly, but at some point I was complaining about receiving an engineering drawing in mils. My friend swiftly turned his head, looked me in the eyes and said “mils are a bullshit, made-up unit.” I found his visceral, candid and accurate response refreshing. When later talking with Sven, another pro-metric friend, about mils, I thought I heard him call them “feral units.” The designation was perfect. A feral organism is one that has changed from being domesticated, to being wild or untamed. The word derives from the Latin word fera which means “a wild beast.” A mil is a feral engineering unit indeed.

What is a mil? Well, according to engineering folklore a mil is one-thousandth of an inch. The British use the word mil as a slang term for millimeter. Confusing a unit which is 25 μm with one that is 1000 μm,  is an error of about a factor of about 40. When American
engineers work with British engineers on a project, this could be the source of some serious mistakes.

The two feral units which are probably the most dangerous to humans, you probably use every time you follow a cooking recipe. They are the teaspoon and tablespoon. Some readers may almost find this assertion preposterous, but, as I will demonstrate, it is not. In America we use the terms Tsp for teaspoon, and Tbl for tablespoon.

When I was growing up, and became sick, my mother would obtain liquid medicine from a doctor, and then obtain a teaspoon or tablespoon from our silverware drawer. Unfortunately, there is no requirement that a teaspoon or tablespoon of flatware hold a prescribed volume. The label on the brown bottle would have the dosages typewritten in terms of teaspoons or tablespoons.

If one looks at a set of measuring spoons used in cooking, metric equivalents are generally stamped or printed on them. A teaspoon is designated as 5 mL and a tablespoon is 15 mL. (In Australia a teaspoon tablespoon is 20 mL) The ratio in volume is obviously three. It is well known that the terms Tsp and Tbl are easily confused. This has led to cases of people receiving 1/3 of the required dosage of a medicine or three times the recommended dosage. Not long ago I exchanged emails with a woman who has become interested in metric issues because her child was incorrectly medicated because of Tsp versus Tbl. Studies indicate that approximately 98,000 Americans die each year from incorrect dosage, and medical errors which can be directly tied back to the lack of the Metric System in the United States

How long has the medical establishment known about the danger posed by feral units? I’m not sure, but here is a column from The Journal of The American Medical Association, dated September 20, 1902 (page 712):

The problem has been understood for over 100 years, since the days of John Shafroth, but nothing is as permanent as American inaction when it comes to adopting the metric system. This adoption must be mandatory and exclusive.  It is my understanding, that legislation mandating over the counter medicines include dosage cups with milliliters, has been perennially thwarted by business and industry.

America is a country that is very sensitive to the welfare of children. The population at most risk from large dosage mistakes are children, yet this needless endangerment  continues–only in America. All other countries (except Myanmar and Liberia) are metric and this is not a health issue. Clearly, feral units that wander the shelves of America have the potential to kill.

The ferocity of Tsp and Tbl are anemic by comparison to the difference between gram and grain. A gram is a metric unit, a grain?–well here what Wikipedia has to say:

A grain is a unit of measurement of mass that is nominally based upon the mass of a single seed of a cereal. From the Bronze Age into the Renaissance the average masses of wheat and barley grains were part of the legal definition of units of mass.

They go on:

The fundamental unit of the troy, apothecary and avoirdupois systems, commonly known as the grain (or less commonly the barleycorn), is nominally based on the grain of barley.

Well, there isn’t just one type of grain for mass, there is the grain, the troy grain, the pearl grain and the metric grain. Don’t even get me started on the insanity of mixed “units” like metric grain and metric ton. The grain we generally talk about is the one where 7000 grains are equal to one avoirdupois pound.

I might hear you say, but we don’t weigh things in grains. Well here is Wikipedia again:

The grain is used to measure the mass of bullets, gunpowder, smokeless powder, and preformed gold foil; it is the measure used by the balances used in handloading; bullets are measured in increments of one grain, gunpowder in increments of 0.1 grains. Moreover, the grain is used to weigh fencing equipment, including the foil. In archery, the grain is used to weigh arrows and arrow parts.

Unfortunately the grain is also sometimes used in medical prescriptions in the US, this is where an almost 65:1 error is possible. If the only legal system for trade in the US was exclusively the metric system, and it was enforced, it’s all grams—period, it’s all milliliters—period, it’s the simplest way known to describe these quantities—period.

This is true only  if we use accepted SI designations. For instance, the representation for milligram is mg and microgram is μg. This is very important as the dosage difference between milligram and microgram is a factor of 1000. Unfortunately, vitamin bottles use MG for milligram and MCG for microgram. These are feral designations.

A Dateline NBC program entitled: “The Validity of Vitamin Bottle Labels” which aired on March 18, 2012, relates the story of a number of women who were poisoned taking vitamins. There is no regulation of natural “dietary supplements” so anyone can start a vitamin company. Anyone can just send a list of ingredients to a chemical vendor and create a “dietary supplement,”  and offer it for sale to the public. One business used MG when the dosage was supposed to be MCG for the amount of Selenium dioxide in a “dietary supplement” concoction. Women taking this “supplement” began to lose their hair, nails, and had joint pain. The use of feral metric designations in medicine, endangers the public health.

It is long past time for the US to require only the domesticated metric units used by the rest of the world. Feral units can then be safely isolated in a museum for all to gaze upon, knowing they are safely confined, where they can do no harm.

Updated 2012-07-11 The information that approximately 98,000 Americans die each year from the lack of metric was added. It was pointed out by a reader, that I also used teaspoon instead of tablespoon in describing the 20 mL measure used in Australia. This was unintentional, and shows the ease of confusion.

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.