How Many Lines are in a Loan?

By The Metric Maven

Bulldog Edition

The first area I recall comprehending was “a block,” whose boundaries I was instructed not to cross. Growing up in a small town, I quickly learned who lived in each of the houses on my block. I knew the name of each family and the first names of each occupant. I was told that 12 city blocks equal one mile. I immediately assumed, without thought, that this length would be that of a single edge of each block in a line. After all, wooden building blocks have equal sides, and I had considerable experience with them. I did not confuse area and linear extent, it seemed obvious. What seems natural to most people is to name areas as an independent dimension. It is so natural that a vast number of defined areas were accepted around the world prior to the metric system. When the metric system was originally developed, this penchant for an area that is arbitrarily defined was adopted. The unit of area in the metric system was given as the are. An are is equal to 100 square meters, because?—I have no idea.

People don’t think about the fact that when expressing total area, we divide the area of interest up using an arbitrary shape of enclosed area. We could use circular meters, or equilateral triangle meters, but we have chosen to use squares with one meter sides. *  The are has sides with lengths that are the square root of 100 meters, or 10 meters. Why choose ten?—no idea—other than area had always been arbitrarily chosen in the past and ten can become a thoughtless fetish for the are. My favorite reference has this set of equivalent named pre-metric areas in terms of an are:

There are about 130 named areas listed in terms of an are, including a line and a loan. Despite what George Orwell might think, this large number of names for non-equivalent named areas only leads to a lack of comprehension, not a clearer description. It does not make them “more human” unless it is meant they produce more opportunity for human fraud.

Metric prefixes were then applied to the are, to create other areas. The most common one used is hectare, which is 10 000 square meters. Why? I can only guess that it’s like
a myriameter of area? Whenever one of the prefix cluster around unity is implemented in the metric system, it produces a kludge. We could have decaares or daa (yes deca or deka has  a two letter prefix da). How about deciares or da, or centiares?—-longtime readers know what I think of this already. Thankfully, the modern official SI is square meters, but once a bad usage has been adopted, it takes an act of Congress (which never happens with the metric system) to change anything. Hectares are still with us, and in the US they are a sure sign of Americans Using The Metric System. Recently on Vice News (2017-01-24) I saw a graph, presented on-screen that showed the increase in poppy cultivation in Mexico had gone from 10 K to 30 Kha indicating the base unit is hectares. It’s easy to understand why this chart has such poor metric usage, it was generated by the White House:

So the White House took hectares and then produced Kilohectares (Kha) by concatenating metric prefixes. So they did not use square meters or square Kilometers, they instead  used ares with the metric prefix hecto, then concatenated Kilo to create Kilohecto. It reminds me of when I lived in a Spanish speaking country and if a person there did not speak English, the answer was to say a phrase louder, modifying an English word so that it sounded like Spanish to that person. I recall a person loudly asking a waiter for “El knife-o.”

So how large is 10 Kha to 30 Kha in metric?  A hectare is 10 000 square meters, with a Kilo at the front becomes 10 000 000 square meters or about 10 square Kilometers. The production has gone from around 10 square Kilometers to almost 30 square Kilometers.

The chart has two axes on it, the other is the amount of potential production in MT, which I can assume is not Montana, but is instead Metric Tonnes. At least they didn’t need to use another prefix with MT. Would Mg for Megagrams really have caused that much confusion, when MT is not even defined on the graph.

So in 2011 about 11 square Kilometers could produce about 30 Megagrams of poppies or about 2.7 Mg/Km2, by 2015 it is about 70 Mg over an area of 28 Km2 or about 2.5 Mg/Km2. The yield per square Kilometer is about the same.

This chart was only on screen for a few seconds, has two axes, uses ill-defined units, and is therefore typical of what I often see in the media. Telling the story is generally more important than conveying information. The measurement free-for-all that is the US, conspires to reduce our numeracy the same way that 130 named areas dilutes the meaning of 100 square meters.

* A more in-depth discussion of this choice for area shape is found in The Dimensions of The Cosmos (pp 29-31).

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The Right Way, The Wrong Way and The American Way

Battlebots Trophy -- A nut with a 5 inch diameter hole with 4 threads per inch
The Battlebots Trophy — A nut with a 5 inch diameter hole and 4 threads per inch

By The Metric Maven

GAO Report Edition

Fasteners are ubiquitous. In physical design, they are everywhere. The image to the left is the current Battlebots Trophy, a giant nut. As of 2016, this nut celebrates US obsolescence with its archaic 5 inch diameter hole and four threads per inch.  The 1978 GAO report has an interesting chapter on fasteners, what happened, and what didn’t. The first sentence of the fastener chapter reads:

The U.S. fastener industry which was originally opposed to metrication, began conversion efforts in 1970 in order to maintain its markets.

The industry found that in the 1960s their major customers were moving toward the metric system. One would think the US fastener manufacturers would have been in favor of metric by 1978, but the story is more complicated than expected and perhaps too American. The Report has a nice description of a fastener:

A fastener is anything which holds two things together. Nuts, bolts, screws, rivets, cotter pins, and nails are a few examples. (See following page.) Of these, the United States produces approximately two million different types. Fasteners can hold together a vast number of items. For example, a telephone is held together with about 70 fasteners. Jumbo jets contain millions; and for one model, fasteners costs represent about 10 percent of the plane’s total cost. In short, much of the nearly $2 trillions U.S. economy is held together by the $2 billion fastener industry.

The report notes that a considerable increase in the use of metric fasteners is taking place in the US. The domestic fastener industry was also under pressure from imported Olde English fasteners. At the end of the 1960s, no US engineering standard for metric fasteners existed, but an international standard did. US industry representatives claimed that the international standard had too many sizes and thread types. The values of these sizes did not follow a logical pattern it was alleged.  If the US fastener industry was going to become metric, it was argued that the US should create a new fastener system that was:

….as perfect as possible. Also, the industry did not want to give a competitive advantage to foreign producers of metric fasteners. It was felt that the foreign producers would gain an advantage if the U.S. industry merely accepted the existing international  standard for metric fasteners in its entirety.

Yes, we in the US were going to produce a “more perfect fastener” or perhaps even a perfect fastener, and in January of 1971 the report “A Study To Develop An Optimum Metric Fastener System” was released by the Industrial Fasteners Institute. The study was presented to the ten largest corporations in the US as well as the National Bureau of Standards (NBS), and technical bodies in Canada. The selected group was unanimous in its view that a detailed study should be undertaken. The GAO Report states:

The Committee’s ultimate objective was to design a metric fastener system which would be so attractive technically and economically that it would become the single internationally accepted system of threaded fasteners. (7-5)

An unshakable US faith in technical Darwinism, coupled with the belief the US would create the fittest fastener meme propelled this new study. The Special Committee published its results in 1973. It recommended a fastener system with 25 sizes and a single thread type. The first metric fastener standard based on these recommendations was released in 1974. Before the standard was completed, the new system was encountering international resistance. Britain and German standards representatives released a paper called “Why Should the International Standards Organization System for Metric Fastener Threads be Changed?” It argued that the costs and confusion were unwarranted, “the technical advantages were minimal, and the system could hardly be called “optimum.” There were complaints of protectionism and everyone having to start all over again. (7-6).

The discussions continued from 1973 to 1977 as the ISO negotiated with its US members. The US representatives finally backed off from the proposed changes to the international standard. The US standard became essentially the same as the preferred series of the ISO standard.

There was controversy about the strength grade of fasteners in the 6 to 18 millimeter range. Europeans used an international strength grade of 8.8. It has a strength capacity of 116 000 pounds per square inch. The comparable US SAE was grade 5, which has a strength of 120 000 pounds per square inch. This is about a three percent difference. It was recommended the next higher grade 9.8 be used. This fastener has a strength of about 130 500 PSI.

The Europeans went along with the proposed change, but only the US automotive industry adopted the higher grade. US farm equipment, Canadian and European manufacturers decided to use 8.8 for their threaded fasteners. The unavailability of fasteners that met the US requirement caused concern that an 8.8 fastener could be interchanged for a 9.8 version during a repair. If 9.8 was not available, it would be necessary to use 10.9, which requires an alloy steel.


The report next focused on the head sizes for the fasteners:

A major problem arose during the attempt to reach agreement on the hexagon head size for three fasteners. This was probably the most hotly debated and difficult issue considered during the 1977 ISO meetings. The schedule below shows the head sizes wanted by the United States, those used in Europe, and those agreed to at the meetings.


The Optimum Metric Fastener System study had shown that the head size for a number of fasteners was unnecessarily large. International standard sizes were widely used in Europe, but the European representatives had in 1975 agreed to reduce the head size 1 millimeter on each of the three sizes. The U.S. representatives agreed to the compromise sizes in the earlier meetings, but in 1977 returned to the demand for a smaller head for the 10-millimeter fastener size.

The Europeans would not approve an inclusion of a 15 mm head and the US would not compromise. The official standard became 10, 12 and 14 millimeter diameter fasteners with 16, 18 and 21 millimeter heads respectively. The US would use these and the 15 mm head. It became possible that several head sizes might be used for these three fastener sizes. The Report noted:

Head sizes (like strength grades) are an example of an international standard which is formally agreed to on paper but not uniformly adhered to in practice. (7-8)

The European view was that the benefits of the changes to the new system did not justify the expenses involved. The fastener standard is voluntary, and the US could do whatever it wanted. This impasse could leave US fastener manufacturers holding the bag. The GAO report states:

An official of one company told me he had stuck his neck out and stocked six metric sizes in 24 lengths. The stock included the 6.3-millimeter fastener which was one of the U.S.-proposed sizes that did not gain international acceptance. This size was being used by a major automobile manufacturer in its 1977 and 1978 models. However, the automobile manufacturer has dropped it for future models.

It was noted that maintaining Ye Olde English and metric fasteners in the US could cause considerable difficulty:

It is virtually impossible to visually identify some sizes of customary-threaded fasteners from similar-size metric fasteners. It is possible to mismatch 36 combinations of customary- and metric-threaded fasteners. The result could be either stripping during assembly or full assembly with 25- to 60-percent loss in load capacity. Thus, the accidental mismatch of fasteners could result in fastener failures.

This is a very good argument for a quick metric switch-over, with an M-day, and no “transition period,” rather than waiting for the magic of the Metric Philosophers technical Darwinism to accomplish this task over an undefined period.

On April 25, 2014 (2014-04-25), Joe Greenslade of the Industrial Fasteners Institute gave a presentation titled “Metric Fastener Standards Transition”  His view is that one metric fastener system should be used throughout the world. Mr. Greenslade calls the US attempt to create an “Optimum Metric Fastener System” a “misguided move!” He claims that from 1975 to 2013 there has been a slow but gradually accelerating adoption of metric designs.

Greenslade identifies three different fastener systems, ISO (International), DIN (German) and ANSI/ASME/ASME/SAE (US). He sees the US Optimum Metric Fastener System (OMFS) as a misguided philosophy of “since we must change we will do it better than you Europeans do.”  The OMFS attempted to eliminate fine threads, this “simplification” was rejected. The US introduction the M6.3 X 1 fastener simply because we wanted a metric version of a 1/4-20 Ye Olde English fastener, rather than using a standard M6 x 1.0 was rejected. The introduction of a new thread gauge was not accepted. The US wanted to replace the hex head with a new spline head, but that was also rebuffed. The changing of hex sizes (head sizes) by 1 millimeter on M10, M12, M14, and M22 is still causing confusion to this day. The US has finally withdrawn its proposed “optimum” metric standard.

The two metric standards that remain are ISO and DIN. DIN is very, very close to the ISO standard. They are 99.99% interchangeable, and 90% identical. The German DIN standard is to be replaced with the ISO standard. When US customers now ask for ISO they are often told “we do not stock any ISO — only DIN.” Greenslade indicates that a search for dual DIN/ISO designations on existing drawings and parts lists should be undertaken, and in these instances they should be edited so that only the ISO number is used. He also suggests that all new product design drawing designations be only ISO. Greenslade offers numerous examples of this existing redundancy “out in the wild.” The long term objective for the USA should be to use ISO and forget the past.


The US introduction of an “optimum” standard in the 1970s has the fingerprints of American hubris all over it. Rather than finally bring some order to the chaos that is side by side Ye Olde English fasteners and metric, by eliminating the “custom”-ary versions, and using ISO metric exclusively, we instead opted to show everyone “how to do it better.” History has not judged us favorably, and the exercise in imposing a US metric “standard” on the world continues to cause discord and confusion to this day. As has been said many times “the great thing about US standards is there are so many to choose from.”

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Related essays:

Without Metric Threads We’re Screwed

A Hole in The Screw Head