Monthly Archives: April 2012

Don’t Get Engaged with Gauge

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By The Metric Maven

Bulldog Edition

One day many years ago I had a strange experience with a word. It lost its meaning. I could pronounce it, and think about it, but the word had become temporarily disconnected from its assigned meaning. The sensation was one of disengagement with a description of  my world. Thankfully I experienced this for only a short period of time. Recently I discovered this phenomenon  has a name: semantic satiation. Here is a definition:

Semantic satiation (also semantic saturation) is a psychological phenomenon in which repetition causes a word or phrase to temporarily lose meaning for the listener, who can only process the speech as repeated meaningless sounds.

Semantic satiation describes a situation where a word has a meaning but it is temporarily lost. I have also experienced the loss in meaning of a word that is not just used in a repetitious manner, but is also assigned a multitude of meaningless meanings. This word also has at least 14 definitions. This mercurial word is gauge.

We have 12 gauge shot guns, wire gauge, railroad gauge, drill bit gauge, stubs iron wire gauge, sheet metal gauge, film gauge, loading gauge, structure gauge, and who knows how many dimension gauges of which I’ve never heard.

But gauge can also refer to a measuring or comparison device such as an air gauge, rain gauge, gauge blocks, water gauge, needle gauge, and many more.

The idea of gauge is batted about by Engineers and technical people with certainty—as if there should be an immediate comprehension. Yet, if you examine gauge as a dimension standard, you will immediately realize this is an oxymoron. Gauge is a dimensionless number. Gauge seems to be the measurement equivalent of the throw away phrase “Ya know what I’m sayin’?”

For instance, let’s suppose I want to drill some holes into a printed circuit board for a solid bare wire to pass through. I want the wire to have a hole that is as close to its diameter as possible. If I had a metric wire with a diameter of 1 mm, I could go to my drill index and select a 1 mm drill bit. It would then be easy to drill a hole as close as possible to fit the 1mm wire. Metric wire sizes correlate with metric drill bit sizes. It’s so easy even a caveman could do it.

There is only one problem with this simple solution, I live in the United States and thus far I’ve found no distributor of metric wire. I must rely on American Wire Gauge for wire sizing. I must go to a wire gauge table and find the American Wire Gauge number is 18 (AWG 18), for wire which has a 0.0403″ diameter (1.024 mm). The wire gauge numbers go from 0000 (0.4600″) to 40 (0.00314″) with larger gauge numbers proportional to smaller sizes.

Now I need to find a drill bit with a 0.0403″ diameter. The gauge sizes for drill bits are from 1 to 80 and A to Z. I locate Drill bit gauge 59 which is 0.041″ (1.041 mm). This is close to 1 mm and probably acceptable, but the wire gauge number is 18 and the drill bit gauge number is 59. There is no correlation. Don’t ask 18 what?, or 59 what?, they are just dimensionless integers, chosen by our infallible Anglo-Saxon ancestors–who used three barleycorn in a row to define an inch—and used the weight of 7000 barleycorns for a pound.

Why does the drill bit gauge designations change from numbers to letters?—I have no idea. This complete lack of correlation between gauge sizes of wire, and drill bits, illustrates that gauge is a meaningless dimension designator. Gauge simply stands between you and a useful, accepted, accurate, and understood dimension—like millimeters.

I find myself astonished that there is considerable resistance to metric system adoption, even when I point this irrationality in gauge designation out to machinists. It begins to look like they want a set of mystic runes to read, so their profession remains esoteric, and difficult to understand by outsiders. Why have a system this confusing?—when there is one—the metric system—which is ready to go. If you have 0.7 mm wire and a drill set with a 0.7 mm bit, what’s to dislike? No look-up tables, no strangely odd numbers and letters, just drill the hole.

How about American Standard Sheet Metal Gauge?  Let’s take 19 gauge sheet metal, how close to a millimeter thick is that?  Well it depends on the material:

Gauge       Steel               Stainless Steel           Aluminum                  Zinc

19     0.0418″ (1.06 mm)     0.044″ (1.1 mm)     0.036″ (0.91 mm)     0.060″ (1.5 mm)

So what does gauge number mean if the dimensions are all significantly different! It doesn’t seem to represent a constant dimension.  Why on earth can’t we just shoot for say 1 mm +/- a tolerance?—and have numbers with units attached? Or, if there is a manufacturing reason for the differences, just use millimeters. The larger the gauge numbers for sheet metal, the smaller the thickness. If we want the closest 1 mm drill bit, it’s 59 gauge. The closest 1 mm wire is 18 gauge.  The closest 1 mm sheet of metal is 19 gauge. We won’t even go into Stubs Iron Wire Gauge, and tubing gauge. There is no rational correlation between gauge number and physical dimensions.

A 12 gauge shotgun has a barrel diameter in which twelve balls of lead, of the same diameter as the barrel, are equal to one pound. It takes twenty lead balls of the same diameter as the 20 gauge shotgun barrel to equal a pound. What if you obtain a .410 shotgun?–well that’s in caliber.  I would argue that 9 mm is more descriptive than 12 gauge, 20 gauge or .410, even to Americans.

The use of gauge, as a  size description in America,  is a perfect illustration of the completely irrational dimensional arrangement of our building construction materials. They are the materials that drive our physical economy.  This causes confusion and waste, for no reason. Our system is long past being ripe for reform—it’s rotting. I don’t understand why the American public, and the technical community, doesn’t demand mandatory conversion to the metric system. I just can’t gauge why.

Related essay:

Without Metric Threads We’re Screwed

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.

The Metric Hogshead, A Unit Whose Time Has Come

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By The Metric Maven

Bulldog Edition

Arnold – The Metric Hogshead Inspiration

When I was a very young boy, I often watched the Gerry Anderson program Fireball XL5. Space exploration was paramount in peoples minds at the time. In the program, the puppet crew of the spaceship, became space happy with the space prefix.  According to my friend Sven, they had a space circus, space generals and it was insinuated that a space ice cream truck existed. The magic prefix “space” could transform any ordinary mundane object or concept into a modern one that was now  space ready.


This type of magical prefix incantation practice somehow became a tool for US metric aversion. If the metric system is the wave of the future, there’s nothing wrong with our old units that affixing a prefix can’t fix. Sometime in the past, it was decided by metricphobes, that they could create metric imperial units out of the vacuum of space, by merely using the word metric as a prefix. Poof! suddenly we have a metric ton, a metric grain and a metric carat.


Metric ton, now there is a unit worth banishing, yet it is also officially called a tonne, so you will know it’s a metric ton and not a long or short ton. Some creative person even decided to double down on the absurdity, and sometimes I see it written as metric tonne. A tonne by any other name would measure as bad.


The original word ton is of obscure origin and seems to be related to the weight of a wine cask, called a tun. How much mass does a metric ton have? 1000 Kilograms, or more properly, 1 Megagram. So why don’t we just call it a Megagram, instead of a metric ton? I have no idea. The confusion between metric tons (1000 Kilograms), long tons (1016 Kilograms) and short tons (907 Kilograms) has caused a number of trade misunderstandings—to this day. The recommended symbol is t for tonne. With mt or MT meaning metric ton. Of course we could just use metric directly, and call it a Megagram with the respresentation Mg. Well, we can’t use this symbol, because people could possibly confuse it for a milligram—that’s what I’m told.


Obviously mg and Mg could be confused, but would it really be a problem in practice?
Am I to believe that no one, other than a fisherman, would be able to figure out that a boat which has caught  34 mg of fish would not make sense. Or be so credulous, if I purchased
a bottle of vitamins, that I could easily confuse 200 mg tablets for 200 megagrams? The two units are 1000000 times different. I’m also to accept that two representations of metric ton, mt and MT solves the Mg problem?


The difference between a milligram and microgram is of concern to pharmacists. This could be a serious error. I note that for milligrams the representation used is mg, but for micrograms, it’s MCG. Perhaps we could have MAg?–for Megagram—or some other three letter acronym, and ditch the metric ton, which is neither metric, nor a ton.
A metric grain is a unit we can clearly do without. Imagine how confused Americans would become if we did not offer them 5 grain aspirin, and they were offered only a 325 mg label on the package. I believe the answer is not at all. Ask anyone on the street how big a 5 grain aspirin is. What do you think the odds are they would know?


A metric carat is 200 milligrams. The word carat is a word for carob seed. Yes, we apparently need a metric value for a carob seed in order to make mass measurements of gemstones. We can’t use metric grains, they’re wheat!–and are 1/4 of a metric carat. They are obviously not suited for gemstone measurement—only carob seeds are.
The metric carat is then subdivided into 100 points of 2 mg each.  The reason we could not just use milligrams would be???? I don’t know, but could it be, that if we were in space we would use space carats instead? Or perhaps there is great concern by jewelers that we would confuse a 20 mg diamond with a 20 megagram one?  We must certainly guard against this danger. With a density of 3.5 milligrams/cubic millimeter, a 20 mg diamond would have a volume of 5.71 cubic millimeters. A 20 Mg diamond, would have a volume of 5.71 cubic meters!

What is the reported weight of the Hope Diamond? It’s 45.52 carats! Where are the points! The units are carats and points–right? I hate to go against the respected “tradition” of diamond merchants, but 9.1 grams seems like a more understandable value. That is about nine plain chocolate  m&m’s. Now don’t confuse them for mm.

The Smithsonian describes the Hope Diamond as weighing 45.52 carats, with dimensions of  Length: 25.60 mm, Width: 21.78 mm, Depth: 12.00 mm. Would it confuse people more if it were 9.1 grams with those length dimensions, all in metric?

There are eight different lattice structures of carbon, why does carbon in a diamond lattice deserve  its own pair of metric-non-metric measurement units? One certainly can’t argue that it’s somehow color—diamond dust is black. I once saw the diamond dust Andy Warhol used in his work Andy Warhol’s Diamond Dust Shoes at The Des Moines Art Center, it’s black, and hypnotically shimmers.

The use of carat appears to demonstrate a significant advance in marketing, but a retreat for the science of measurement. The carat, metric or otherwise, should be cast into the nether-regions and never allowed to return. Grams are satisfactory thank you.

When  I was in college, an important measurement mystery confronted me: how much beer is in a keg? I seemed to get multiple answers. Finally I was told by a beer distributor that there is no standard beer keg size. This is still true to this day. This is from Wikipedia:

“Since keg sizes are not standardized, the keg cannot be used as a standard unit of measure for liquid volumes. This size standard varies from country to country and brewery to brewery with many countries using the metric system rather than U.S. gallons.“

It’s clear to me that something must be done about this egregious trespass by brewing companies.  How can we continue to allow them to prey on innocent drunken college students! I therefore propose the Metric Hogshead, defined to be 200 liters. A metric keg would then be defined as 50 liters or 1/4 of a metric hogshead. Finally standardization has been imposed on a runaway system of measuring beer. You’re welcome America!

What I’m lampooning here, is what the world had prior to the metric system: endless, unnecessary, different, and inconsistent measurement units. Imagine if gasoline, milk, water and paint all had their own volume units, that changed from town to town and country to country around the world. The chances of making a mistake or being deliberately cheated by inconsistent and arbitrary weight and measurement definitions would be ubiquitous.  That is what we had before 95% of the world’s population agreed upon one uniform system of measurement for volume–the liter. It is only in the US that we would rather makeup imaginary versions of metric measurements, and create metric kegs and metric hogsheads rather than legislate the metric system. School’s Out, let’s forget metric hogsheads, metric tons, metric grains, metric carats and just use the metric system.

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.