Category Archives: Metric Aversion

When PigFish Fly

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Dr Clayton Forrester Creating a PigFish

By The Metric Maven

Bulldog Edition

The lack of any weights and measures reform in the US has created an odd situation. Both Imperial and metric parts often make their way into US product designs. This metric advocate has called this situation where metric and imperial are mixed—often on the same part—PigFish. It makes as much sense as sewing the head of a pig on the body of a fish and expecting something good to come out of it.

Recently I needed to purchase a house fan. After returning from the store, I discovered to my surprise I had to assemble the base. I was not prepared for that, or the associated drawings.

In Figure 2, there are two screws called out as #8 x 3/8″.  I have written about the absurdity of imperial screw threads in previous blogs. This is a #8 “gauge” screw which is 3/8 inch in length. So far this is not untypical for an American made product. The screws fasten the two halves of the fan’s plastic base together. Then in Figure 3 we are to attach the base to the fan itself. The screws to accomplish this are designated as M5 x 1/2″!  This is serious PigFish. A screw with 5 mm thread is called out as having a length of 1/2″. Metric and imperial on one part!

The mixture of imperial and metric fasteners in the US wastes an incredible amount of time, yet is invisible to most people. As an example, my father often works on equipment at a printing company. One day recently he had to work on a piece of broken equipment. He noted it was manufactured in the US, and therefore assumed that it was imperial. He went and obtained imperial wrenches, only to discover when the tools didn’t fit, that it had been designed in metric. The situation becomes much more complicated in the only country in the world which has no aversion to using both metric and imperial in the same product. One needs two sets of tools to support this absurdity, which increases the cost of tools in the US needlessly. When a product incorporates imperial and metric randomly—working on it becomes a guessing game which further wastes time. I have no idea how much this costs when added up in a nation the size of the US, but it makes it easy to believe the estimate that non-metrication costs each person in the US $16.00 per day.

My Father received an outdoor grill as a gift this last Summer, and when putting it together, noted that metric and imperial were again mixed and matched. There are 1/4″-20 x 3/4″ screws with #8 x 3/8″ self tapping screws and 7 mm lock and flat washers with 1/4″ nuts.

When confronted with this farrago of parts, an American gesticulating with his gill of grog in hand might state: “Well all you’ve shown me is a couple of small items, where the parts are all provided, it’s no big deal.” Well then, let’s explore the potential danger created when PigFish fly.

Michael Milstein wrote about this problem in the March 2001 edition of Air & Space magazine. He notes:

…..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.

I’m not convinced NASA ever gave any serious thought to building the US part of the International Space Station (ISS) in metric. Milstein further relates:

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.

It is quite surprising how sanguine NASA is about the ISS, when the Mars Climate Orbiter, and the DART Satellite, both had “mission failures” because of metric/imperial conversion problems.

The International Space Station — PigFish In Space

I recently attended a social function where I met a woman who has a PhD in Mechanical Engineering. She and her husband had both been involved with the ISS. He is a metric advocate, and along with a number of other Engineers lobbied hard for metric only construction. They filled out the numbing amount of paperwork and invested time to make the American part of the ISS metric. The request moved upward, and then tumbled back down with a NO attached. Why do we continue our self-imposed technical segregation from the rest of the world? In Aerospace one never knows just who makes this decision, it just moves down through the bureaucracy and splats on your desk.

“Hey Fruit Loops. Are the tools needed imperial or metric?”

What really struck me was the consequences of this choice. When the astronauts on the ISS need to make a space walk to repair or work on the ISS, they must take both metric and imperial tools with them. Strange we can justify two sets of payloads, rather than using metric exclusively. I was gobsmacked at the choice to allow imperial with metric. Because there has never been any compulsory metric legislation in the US, our astronauts must have two sets of tools to work on their equipment in space, just like my father has to at his print shop. We also impose this need for dual tools on the astronauts from other countries, which are all metric. Milstein sums up his view of the US:

We’re like a crotchety old hermit. The rest of the international neighborhood works together and speaks the same language while we huddle in a dark, outdated house at the end of the street (which we share with Liberia and Burma, the only other two nations that have not gone metric), mumbling our own inscrutable tongue of inches, feet, yards, miles, links, rods, furlongs, pecks, bushels, bolts, barrels, fathoms, leagues, acres, ounces, pounds, tons, cups, bales, pints, tablespoons, gallons, hands, chains—most of which have no logical relationship to one another—and all the other aged terms of what is often called the Imperial, or English, system…..

When will we become metric in the US?—unfortunately it may be only when pigs fly. To our great misfortune, and hubris, PigFish have already.

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.

American Software vs. Metric or Mormons Making Coffee

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By The Metric Maven

It is my understanding that during the Bejing Olympics the United States Olympic Committee (USOC) sent measuring cups and spoons to China. This was done because the Chinese could cook recipes from anywhere else in the world but not those from the US.  The non-metric units of the US were a complete bafflement to the hosts, and when the Olympics were over, they just threw the cups and teaspoons away seeing them as useless.

I began cooking with metric about three years ago. It took me a while to understand that I needed a scale with a digital readout in grams. I realized that metric recipes generally use mass instead of volume for dry ingredients. The best chefs do this also. The surprising part was that because of the fact that 50 milliliters of water weights 50 grams, I could actually estimate using the mass of many liquids also. After I became used to using the digital scale and it’s tare function, I found cooking in metric vastly easier, quicker, and more enjoyable than it had been in imperial.

My father has been interested in cooking his entire life. He uses a software package to index his recipes. During a recent visit to his home, my father marinaded steaks and served them for supper. I had not tasted steaks made this way since I was a boy, and later asked for the marinade recipe by email. He sent me the recipe in imperial units as I would expect and then said he had included a metric version from the program so I would not have to convert it. Below is a reproduction of the metric recipe:

After I saw this I wrote my father an email, and asked if he had created this metric recipe  as a joke. No, he assured me, it’s how it came out of the recipe program. I was just gobsmacked by the use of fractional values of centiliters, deciliters and milliliters. According to the metric recipe this would make one cup of marinade.

This strange metric usage made me think of a story told to me by a deceased family friend, known as Skeez, about his experiences in World War II. He talked about riding in troop trains across the US when he was in the military. He gushed and gushed about the great food the women would have prepared for them at each rail stop. Word had “gotten around” that the food at all the Utah stops was good—but don’t drink the coffee. Mormons are forbidden from drinking coffee, but when they were catering for the government, and were required to brew it, the coffee was not remotely as good as the food..

In fact, the coffee served by Mormons was so awful, that considerable speculation went into the method used to make it so completely unpalatable. Some argued that they reheated the same giant container of coffee over and over during the week, and just added more as it decreased in volume. Others thought they just re-used the coffee grounds and added new when it didn’t look black enough. For me “Mormons Making Coffee” was a metaphor for people trying to implement something about which they had only a very slight acquaintance or understanding, and no working knowledge. Like an American presiding over a cricket match.

Whoever programmed the recipe software my father owned, had proved to me that he was like a “Mormon Making Coffee,” but more specifically he was an American Using Metric. There could be no certainty how an American might imagine metric should be used in cooking, and as we see, anything could happen. The two hallmarks of the metric system which make it elegant for cooking, is that it can be implemented to whole value (integer) numbers and only a simple set of prefixes need to be used. It was clear that the confused, and nearly incomprehensible, American measurement vernacular had been imposed on the metric recipe. The use of 1 1/8, 2 1/2 and 1 1/4 with metric values was ultimate proof. As the saying goes, there is no crying in baseball, and no fractions in metric. Metric recipes generally use whole numbers and milliliters–only. And certainly not fractions. Generally spices are measured in volume as indicated, but not with fractional numbers. The brown sugar would be measured in grams. Let’s take this simple recipe and write it as I would have expected to see it.

Don’s Soy Sauce Marinade

125 mL LaChoy Soy Sauce
125 mL Orange Juice
30 mL Lemon Juice
12 grams (15 mL) Brown Sugar
30 mL Salad Oil
3 mL Pepper Sauce
1 Clove garlic, crushed
1.25 mL Black Pepper

Combine ingredients. Use to marinate beef, pork, or chicken before grilling or broiling. I usually put it in a Ziploc bag with the marinade for 2 to 4 hours before grilling…..for a little different flavor add 30 mL of Worcestershire sauce.

Yield 300 mL

This is the best I could do with this conversion. You will note that other than the black pepper, I was able to use whole numbers for the rest of the ingredients.

This episode in my life illustrates something I did not appreciate until a few years ago. Although the metric system is much simpler than the, bloated, and uncorrelated set of units used in the US today, metric should still be even simpler. There are metric prefixes that should be eliminated, which I call the prefix cluster around unity. More formally it’s Naughtin’s 4th law. Some prefixes with units, like the centimeter the centiliter, deciliter should be vanquished. The use of prefixes that are spaced by a factor of 1000 seems to work very well, and is about as simple as it gets for metric system implementation. In cooking, the milliliter is probably all you need for volume, the gram for mass, and the millimeter for distances, and that’s it—done!—nothing else to learn!

American Interpretation of using The Metric System in Cooking

With a metric recipe and proper instructions—perhaps even Mormons could successfully make palatable coffee. But not if that metric recipe was created by imperial to metric conversion software, which had been written by American programmers. Without instruction in the metric system from childhood, and its mandatory and efficient adoption in the US, our software designers will probably continue to use metric in an obtuse manner, and continue to create the illusion that the metric system is complicated, when it’s a paragon of simplicity.

Updated 2012-11-10  Fixed quantities in recipe.

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.