Monthly Archives: November 2012

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.

The Magic Infrastructure

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The Sewer Urchin — The Apotheosis of Cool

By The Metric Maven

Bulldog Edition

Any sufficiently advanced technology is indistinguishable from magic.

Arthur C. Clarke (1917-2008)

I still recall when I was too young to reach the kitchen faucet. I would have to ask my mother to draw a glass of water for me to drink, and wait to grow. I grew up with access to water on demand. I could flip a switch and summon light. The house was warm in winter and cool in summer. The seemingly most important of all the things which provided comfort, was the ability to turn on a television. I took it all for granted as much as there would be oxygen in the room for my next breath. Indeed as far as I knew, it was all based on magic—without cost to anyone.

One Winter the twin lead cable from our television to the antenna on the roof snapped in an ice storm. The image on the television screen disappeared and was replaced with “snow.” The name seemed very ironic. It would be a couple of weeks before the ice on the roof melted sufficiently and allowed my father to reconnect the antenna. Life without television had become unthinkable, and its absence almost unbearable. It was my first experience with the loss of “infrastructure.” The failure began to make me curious about the origin of water and electricity. When I truly realized that somewhere coal was burned to create steam, which in turn rotated an electric generator, and provided electricity it surprised me that it was available 24 hours a day. But like many Americans, I began to take it all for granted and gave it little thought.

My Grandfather had a small cabin in the backwoods of Montana where he often spent weekends. The cabin was made of logs and only had a wood stove, and cabinets for food storage. The nearest electricity was 27 kilometers away. An outhouse was conveniently located about 10 meters from the cabin. We obtained water from a nearby creek. It was quite an adventure with wildlife all around, the smell of lodge pole pine in the air, and the multitude of stars one would see in a night sky without light pollution was sublime. A single gas mantle lantern illuminated the interior where we both read books into the night.

It was all very pleasant, but after a couple of days without a shower, or running water, or indoor plumbing, or electricity, or a telephone, it was nice to know I could quickly return to a home with modern infrastructure. The weekends offered solitude and relief from the modern pace of life, but also provided considerable respect for why our ancestors created infrastructure in the first place.

As a boy, I survived an F5 tornado passing over my grade school building. When I was evacuated, not long after the tornado had passed, the phone lines, power lines, trees and all the infrastructure of the small town in which I resided was devastated. There was no electricity for 1-2 weeks as I recall. The water wasn’t safe to drink. I stayed at a relatives house while the infrastructure of my little town was re-built. For months afterward the sounds of chainsaws and the movement of utility trucks was a constant.

Path of F5 Tornado

My interest in American infrastructure was greatly rekindled when I listened to a lecture by Scott Huler,  and later read his book On The Grid. What intrigued me was how oblivious I was to it all. When most people I know talk about infrastructure, it’s  usually to complain in some way. My Uncle used to quip: “There are two seasons in Minnesota, Winter and Construction.”

Since my youth, I had seen multicolored spray paint on road surfaces, but gave it little thought. Huler provided a “decoder ring” for the colored lines, which are standard throughout the country. Reviewers of Huler’s book have noted with annoyance that it is a book without any illustrations. I can agree with their sentiment, but he provided a useful Infrastructure Rosetta Stone with this graphic:

Each color of spray painted line, defines the path of Gas Lines (Yellow), Water Lines (Blue), Sewer Pipes (Green), Electrical (Red), Communications (Orange). When the path enters a lawn, small plastic flags with the same color mark the path across a lawn. White lines indicate the excavation limits. When you see these colored lines appear, you can be confident that construction will follow.

The colors indicate the area has been surveyed. As discussed in a previous blog, surveying is still done in chains, even though the most important advance has been the use of GPS, which is meter based. The GPS metric units are all converted to chains and feet by the surveyors. When an area is leveled with bulldozers, GPS is again used. Huler’s book illustrates the undisciplined way we use measurement:

Survey of Australian Subdivision in Metric

“We have an alarm that will flash on the screen if you are getting out of tolerance. I think we have it set at 2/10 of a foot”—that is less than 3 inches. If that’s not enough, there’s a system called Millimeter GPS made by a company called Topcon. “We can measure to the nearest millimeter today.” (page 18)

How about we just use millimeters? The alarm is set to 60 mm, and it’s possible to measure to the nearest millimeter today.

The way we channel storm water has decreased the amount of fresh water that returns to the water table. It instead shoots down storm drains into rivers and ends up in the sea in a short period of time. To mitigate this problem, Civil Engineers have been adding back meanders and have slowed down the flow so that more fresh water is retained. Scott Huler spends a considerable amount of time tracking down the path water takes in Raleigh, North Carolina. Here is how he describes the water flow with imperial units:

A USGS stream meter at the park later allowed me to retrieve only the value of the flow I was wading through: It was about 4/100th of a cubic foot (about a third of a gallon) per second, which is about 20 percent below it’s mean value over the last 12 years.(page 49)

Let’s convert this over to metric and see how it reads:

A USGS stream meter at the park later allowed me to retrieve only the value of the flow I was wading through: It was about one liter per second, which is about 20 percent below it’s mean value over the last 12 years.

The actual value is about 1.13 liters, so he could have also said that or 1130 mL. but the value seems too precise with the caveat of about attached twice in the original, so I just rounded it to a liter. I’m sure Scott Huler reported with values the USGS provides, and until we can change to metric, we will be collectively stuck with multiple inarticulate measurement units. Another example is:

Raleigh gulps as much as 50 million gallons of water per day, which require the intake to suck out 80 cubic feet per second. (page 54)

Which could be written in metric as:

Raleigh gulps as much as 200 million liters of water per day, which require the intake to suck out 2000 liters per second.

Then Huler leads into part of what the thesis of this blog is about:

There are O-rings for hydrants (they all have the same thread; there’s a plan to eventually adopt a nationwide thread so that all the hydrants will have the same connections)……….(page 68)

The National Bureau of Standards was created because of The Great Baltimore Fire which occurred on February 8th, 1904 (1904-02-08). Fire Departments from nearby cities were called, but when they arrived, none of their hose fittings were compatible with those of Baltimore’s fire hydrants, and so the fire kept burning as if they had never shown up. We have had 108 years to solve this problem, but like metric, nothing has happened. Perhaps because it’s all voluntary?

“Together we stand, with shovel in hand, to keep things rolling along” — Ed Norton

The physical infrastructure of the United States is crumbling. This seems to be acknowledged by our citizens, but its implications are not truly understood. Our lives are rich beyond our historical understanding. We have clean water with which we can drink and bathe. We have sewers to remove our waste and waste water. We have an electrical grid which powers all our electrical equipment and natural gas lines which act as an alternative to electricity for cooking and heating. Our communications lines have interconnected the planet. We also have roads, and bridges that allow for transportation, but as Huler points out, a most important part of our infrastructure is in complete disrepair—our railroads.

The era of inexpensive oil is over, and climate change is already accelerating the deterioration of our infrastructure. Most of the world understands this. The obvious response is to build high speed rail in the US so that people may be transported in a more cost effective manner. Transportation is the life blood of a modern economy. If it is not preserved, then an economy will slow and wither. It is important that we construct high speed rail in the US in metric, this will decrease costs for us, and employ Americans to build them, but moreover it would also make our trains ready for sale to international customers. With 95% of the worlds population using metric, it would be foolish to construct trains that required imperial tools for maintenance.

The difference between a nation and a free-for-all is universal access to a common shared infrastructure. The United States has a choice, to rebuild our infrastructure and remain a great nation, or to accept a regression into feudalism with the limit being The World Without Us. The Roman aqueducts and infrastructure did not crumble in a day, and nor has ours. It, like Rome will not be rebuilt in a day either. According to Huler: “China Spends 9 percent of its gross domestic product on infrastructure, Europe spends 5 percent.” The US had decreased from 3 percent to an anemic 2.4 percent. In Huler’s words: “People persist in believing that these systems will somehow maintain themselves, expand themselves, improve themselves without anybody having to put anything in.” There seems to be a considerable number of Americans that believe our infrastructure runs on magic, but it doesn’t, it runs on eternal public vigilance and funding.

The cost will be very large. In 2008 The American Society of Civil Engineers estimated we would need to invest at least $2.2 trillion over five years to bring our infrastructure back from the dead. How would taxpayers feel if I told them I could give them a 10-15% discount on whatever amount we spend on infrastructure?—forever. I suspect they would be for it. It is proverbially known that changing the US over to the metric system as part of a plan to rebuilt our infrastructure, would save at least that much in construction costs. Ten to fifteen percent on $2 trillion dollars is a serious savings.

An overhaul of our infrastructure would be a great opportunity to reform our domestic industries. We could implement metric threads and dimensions for the new pipes, standardize sheet metal thicknesses to metric, reduce the number of fasteners we would need by using all metric, and implement other useful reforms. A metric infrastructure overhaul, would create a workforce well acquainted with building in metric. This in turn will allow our international building contractors, who continue to cling to ACSOWM (i.e. inches, feet etc), to directly bid metric construction projects in foreign countries.

A coordinated metric conversion across all American industry during the repair and upgrading of our infrastructure could bring a sense of national unity. We could tap an American esprit de corps with the rebuilding of our infrastructure and society, and reverse the increasing ennui among the public. I can only hope We The People can find within ourselves, the will and drive to engage in this essential undertaking. For as Benjamin Franklin said: “One never knows the worth of water until the well runs dry.” Let’s not wait for that moment to act.

Related Essay:

The Invisible Infrastructure

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.