One Autumn afternoon I was driving along back roads in the Rockies with my friend Thern. I had been discussing some aspect of metric and he posed a question: “The Model A had only one metric part on it, what is it?” I was floored there was any metric part on Ford’s Model A. I thought about it a while, gave up, and then asked him to reveal the answer. His reply was that it was the spark plugs. They had 18 mm threads. Thern possessed a vintage Ford Model A repair manual and had taken note of this fact. The reason for metric threads? The Europeans were way ahead of the US in the design of spark plugs. Belgian engineer Étienne Lenoir is credited with the invention of the spark plug in 1860. I looked on some Model A forums, and sure enough, there are discussion threads about why the spark plug threads are metric, and asking if they should be reworked so that “standard” spark plugs can be introduced, and such.
I was quite surprised there was any metric part on a Model A. It is the iconic American automobile. When the first Model A was introduced in 1903 John Shafroth was still making his bid to make the US a metric country. It is reasonable to state that well over 99% of the parts which comprise a Model A are Ye Olde English. Today over 99% of the parts in a US made car are metric. Only the bolt heads on the battery post clamps are not metric (those that are used for the bracket to hold the battery in place are metric). Thern tells me that on modern cars (newer than mine) the battery clamps are now generally metric. Pat Naughtin in his first newsletter (Metrication matters – Number 1 – 2003-06-10) mentioned the fact that people in the US do not realize they are driving metric cars, because that fact is not on display:
I wonder why the USA is the last nation in the world to admit the extent to which they use the metric system of measurements. For example, of the 10 000 parts in a modern car, made in the USA, all of them are measured in millimetres to the nearest tenth of a millimetre. But because the speedometer is labelled with the letters ‘mph’, drivers in the USA are generally convinced that they are driving an ‘English Units’ automobile.
Our road signs are all in medieval units, and so there is nothing that would directly indicate that American cars are well over 99% metric.
In an earlier essay I have examined the intellectual grip that familiarity has over simplicity or change. In another I point out that for over 3000 years the design of a bee hive did not change until the 19th century. In the US, innovation has often been associated with a decrease in profit. J.P. Morgan is reported to have said after he had consolidated the majority of electrical providers into General Electric: “Research is unnecessary if you have no competition.” A changeover to the metric system is simply an unnecessary business expense when viewed this way.
In recent years I’ve been exposed to engineering designs at a number of firms. When they use metric, it is often with millimeters, and nothing else metric. I’ve seen more than one situation where a customer is from outside the US, and appears to assume that because the drawings are in millimeters, that the design is metric. In one situation I unintentionally created a brouhaha when I asked if the fasteners were all metric. It was clear I had unknowingly asked a politically incorrect question. They were not. The customer was not happy as they thought the design was completely metric.
What I have noticed is that companies which state they use metric are often creating Potemkin designs. As long as millimeters and meters are invoked the design is thought to be metric, but in fact the rest of the design is left in Ye Olde English. I’ve seen situations where medieval measure screws are used, and in an attempt to “accommodate” metric fasteners, a Ye Olde English screw size that is as close as possible to a metric one is chosen. No newtons per square meter or liters or grams make an appearance, only millimeters do. It is hard to know what motivates this Olde English death grip, it could be some cultural identification, or simply a resistance to change. The use of metric and Ye Olde English in a design is designated as a PigFish design in this blog. Rather than become metric, NASA made the “International” Space Station a combination of medieval and metric. I discuss this in my essay When PigFish Fly.
Whatever the motivation, it demonstrates that left to their own devices US business, education, and all other aspects of our everyday lives will remain as they are—Ye Olde English. Resistance to a government mandate for metrication, is simply equivalent to promoting the continuation of our archaic measures and design methods. As each year goes by without a metric mandate in the US, we become more anachronistic as a nation and as a culture. The only thing Americans seem to be good at these days is talking, and when the subject is the metric system, it is seldom in a positive manner.
The Metric Maven has published a new book titled The Dimensions of The Cosmos. It examines the basic quantities of the world from yocto to Yotta with a mixture of scientific anecdotes and may be purchased here.