The Metric Populist Revolt That Didn’t Happen

By The Metric Maven

Bulldog Edition

On February 12, 2012 CBS News Sunday Morning discussed, in their Almanac segment, the appearance of the first metric road signs in the US, which had occurred thirty years earlier. Charles Osgood states: “Americans content with measuring the old way, were opposed to a conversion, dia-metrically  opposed, you might say.” Then a video clip from the 1970s is shown to validate the assertion. An antagonized man professes: “It’s too damn confusing for a person brought up on the English system.” The formation and later dissolution of the US Metric board is related to the viewer. It is also authoritatively proclaimed that the metric system is based on ten.

The anti-metric Wall Street Journal’s “Numbers Guy” Declared in his blog on March 9, 2012:

Americans foiled 1970s-era predictions of a national shift to metric, the collection of
units such as kilograms and meters designed to be easily computed and scaled by factors of 10.

Reading and listening to American Journalists talk about the metric system demonstrates one certainty, they have never used what they are talking about, and have no working knowledge of metric. They sound as knowledgeable an average American citizen lecturing an Englishman about cricket. The everyday metric units generally used are separated by a factor of 1000, not ten. In everyday life you will almost never encounter anything more than millimeters, meters and kilometers. No, no centimeters—don’t get me started, that’s another blog.

The other notion which has become a proverbial American myth, is that there was a “Metric Populist Revolt” in the 1970s. In order for a populist revolt to occur, one assumes there was mandatory metric legislation, a plan with funding, and the entire society was then compelled to use metric. As this metric mandate was implemented in the 1970s, public spirited citizens gathered with their torches and pitchforks, and fought back the metric invader. Democracy was restored to the Republic and we now live in a metric-free land.

There is just one problem with this narrative, it’s completely fictitious. It’s the sort of narrative Joe Isuzu might have employed. In the 1970s, all of the metric legislation was entirely voluntary. The 1970s legislation had all the impact of a symbolic declaration it was National Macaroni and Cheese day. Without a mandate for change, or availability of metric tools and products, human inertia resists any deviation from our eleventh century Anglo-Saxon barleycorn definitions of weights and measures. We defined a pound as the weight of 7000 barleycorns, and an inch as three barleycorns in a row. Our plastic rulers have fractions instead of decimals and so on. It was all very high tech in the sixteenth century.

There was a US metric board created in the 1970s that had no official power to compel metric usage in the US. But the board’s very existence was deemed unacceptable to a pair of bi-partisan Washington political insiders, and it was disbanded during the Reagan Administration.

Since I first encountered the metric system in my youth, I liked it, and wanted it to become the standard in the United States. Many years passed, and when I found a renewed personal interest in metrication, I wanted to know what happened, or more correctly, why metric didn’t happen. It has been very hard to find out. The complete story is still obscure and difficult to research. This much I do know:

George Washington in his inaugural address asserted that uniform weights and measures were of paramount importance to the United States and would be addressed as quickly as possible. Washington’s aides, and congress let him down through inaction. Bills were offered, tabled, ignored, and met with the indifference. The weights and measures of the US became unwelcome orphans in political discourse.

John Quincy Adams famously examined the US weights and measures question, and like his predecessors deferred the question indefinitely.

Finally, because new imperial replacement standards sent to us by the UK were so flawed we could not use them, Thomas Mendehall had to make a decision the US congress has refused to do for well over a century now. The only standards that were technically acceptable for use, were those provided when the US signed The Treaty of the Meter. In 1878,  The Mendenhall Order of April 5, 1893, became the de facto, un-legislated law which defined all the imperial units in terms of metric ones. John F. Shafroth, of Colorado, began introducing metric system legislation into the House of Representatives around 1895. His bill would have made the metric system the mandatory system of weights and measures for the US. The legislation was not passed, despite a number of attempts. Shafroth continued to urge metric legislation until his death in 1922.

I have thus far found very little history from 1922 until the metric study act of 1968. In 1975 the completely voluntary Metric Conversion Act was signed. There was no plan, no funding, and no vision. Apparently the metric system was expected to organically spring forth, without any effort required. The Metric Conversion Act was amended in 1988 and only punctuated the fact that metric adoption was voluntary—just in case the 1975 Act didn’t make this clear enough. The year 1988 appears to be where the trail goes cold again. Almost no metric legislation appears after that date. One wonders if perhaps the US should apply to the Guinness Book of World Records for a procrastination world record. It’s been 236 years after George Washington’s address on the subject of standardizing weights and measures. After this long without inaction It seems we should be in the running for some kind of record.

While ninety five percent of the worlds population converted to metric long ago, The United States only offered non-binding, vacuous legislation. It is easy to have a successful revolt against non-existent, feckless metric system legislation. You can do it from your living room while asleep in an easy chair. The absence of public leadership by congress and the executive branch, means we all now pay an invisible “Imperial System” tax, of around $16.00 per day per person. Because US citizens don’t realize the costs of the current non-system, it neuters public objection, and encourages the status quo. The most successful parasite, is one who’s existence is not perceived by its host. Taxation without metrication is tyranny!

The myth of the metric populist revolt, is used by people who didn’t even want to try changing over to metric, to explain why there is no use bothering to try now. We tried mightily! they assert, there was a metric revolt! It was horrible!, the nation was torn apart, we can’t even talk about it again! Democracy prevailed. We the people decided, and we are not doing it! This pernicious myth continues to reverberate in our newspapers, magazines, television and blogs. It short circuits discussion, and provides a convenient and illegitimate cover for why we are different, and can never become metric, like the rest of the world did long ago. Other countries of the world reap the financial and intellectual benefits of metrication. We just keep adding the collective cost to our tab–no worries–it will never come due—and so far we haven’t been forced to sober up—and face our metric hangover.. Will we ever?


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.

Without Metric Threads We’re Screwed

By The Metric Maven

I only had a casual acquaintance with screws during much of my working career. Where I worked there were clear plastic organizers with machine screws inside, and label designations outside like #4-40, #6-32 and #1/4-20. I had little idea what the nomenclature meant. One day I decided it was time for me to cure my ignorance. I discovered rectifying this lack of knowledge would be much more of a herculean effort than I expected.

I asked a number of people what the designation #4-40 meant, as I had seen a large number of these machine screws used on projects. The answer was almost uniform, and went something like this: “The 40 means forty threads per inch” I would then ask what the #4 designated. This was generally met with a blank stare and speculative guessing would commence.

Finally I met an engineer who knew the answer off the top of his head. He told me that below 1/4 of an inch the number was in gauge, above that the designation was in fractions of an inch. I was gobsmacked, and could not make any logical sense of this. When I looked up a dictionary definition of gauge, I discovered that it had the alternative spelling of gage. The definition that seems to fit this situation is: “A standard dimension, quantity, or capacity.” What was the dimension of the gauge size below 1/4 inch? After some research I found this answer:

“In Unified threads (measured in inches) there are numbered diameters #0 through #10, with 0 the smallest and 10 the largest. (Diameters #12 and #14 may also be found, but are usually on older equipment and needed for repairs or restorations.  #14 is close to, but not exactly the same as, 1/4-inch.) The major diameter in Unified threads = 0.060″ + 0.013″ x (numbered diameter). So #2 has a major diameter of 0.086″. The odd numbers exist, but the even numbers are in far more common use.”

WHEW!!! This is how we designate screws in the US?! So you take 60 thousandths of an inch and add the gauge number times 13 thousandths of an inch to obtain the size in inches from the gauge number!!!? This is what we viscerally protect as a rational method of articulating screws in the US? But the given diameter formula only is valid for the gauge numbered screws. Above 1/4 inch, the values are directly in inches—well as directly as a fraction may be called “direct.” One generally has to compute a decimal value from the fraction to actually perform computations. It is clear that even this demarcation at 1/4 inch is an apparent ad hoc attempt to merge the two separate nomenclatures, given that #14 is close to 1/4″.

We see that  #14 would be 0.242 inches and #1/4 is 0.250 inches. One can see that this is only a 0.008″ or 0.2 mm (200 um) difference between screw diameters. It is not difficult to imagine many situations where this size similarity caused mistakes. The answer offered to solve this problem appears to be “just stop using #14.”

Recently I met a former machinist who smiled when I told him “I only use metric in my designs.” His countenance indicated he really didn’t see that changing to metric was anything other than a frivolous, fringe issue. I looked at him and asked a simple question: “what size drill bit do you  choose to allow a #4-40 screw to just pass through a sheet of material?–to produce a friction fit.” Suddenly his face became blank with uncertainty. “What I usually do is get a pair of calipers and measure the diameter in inches and then choose a drill bit.” I then asked what type of drill bit designation he then used to obtain the correct drill bit size based on his measurement.

There is more than one option. A fractional set of drill bits does not match the decimal inch value he measured with a calipers. He would need to first go to a decimal equivalent chart and choose the closest fractional drill bit size. A  #4 screw has a diameter of 0.112″ according the the formula. The closest fractional size is 0.125″ which is a 1/8 inch drill bit. That’s as close as it gets! There are also US number and letter size drill bits, but I’ve  tortured myself long enough explaining this Rube-Goldberg method of just trying to figure out what size drill bit to choose, for a given screw, when using imperial measurement. I didn’t inquire, but I suppose the former machinist is content to measure all the candidate drill bits with his calipers until he finds one acceptable. How is it we are content to have size designations on screws and drill bits that have no correlation?—and reject any change or reform?

Let’s now explain how screw threads are designated in metric. The closest size screw in metric to a #4-40 machine screw is M3. What does M3 mean? Well, the M means metric and the 3 means three millimeters in diameter. My metric drill index has a three millimeter diameter drill bit, which if I then drill a three millimeter hole, allows the three millimeter M3 screw to just pass through the plastic, metal or whatever sheet material I drill. Yes I have done this, it works. It’s that simple! If you want some clearance choose a 3.1 mm drill bit or 3.2 mm. They’re both standard sizes.

When Australia switched to the metric system in the late 1970s, their manufacturers quickly discovered they could get rid of a large amount of screws and bolts they stocked. One car manufacturer was able to reduce their inventory of fasteners by 80% which saved considerable money. The small business community in this country, who use commonly available imperial fasteners, don’t realize that without metric threads they’re screwed.

Related essays:

Don’t Get Engaged With Gage

A Hole in The Screw Head

Yes! We have no metric drill bits.


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.