Metric vs. Imperial Units

When we’re taught how to measure things in grade school, we’re handed a ruler, or maybe we see the tape measure in the toolbox as infallible objects. After all, how can these absolute objects of measurement ever be any different? But most people would be surprised to know that measurement has lived a convoluted life – tied to the history of three of the most powerful countries in the 18th century – France, Great Britain and the United States. If the tides had gone just a bit differently, perhaps, CFI would be making more metric components, or most surprisingly, we could’ve added a whole other type of measurement to the standard Metric/Imperial mix.

In the United States, inches, feet, and miles are used everywhere – even in the components industry as we regularly create nuts. Think of the last time you looked in a toolbox, you probably pulled out a 7/16 wrench only to find out that it was just a bit too large, fumbling around until you found the 11 mm wrench for the proper size.

So what is the reason behind all of this madness? Why is there effectively two sizes for the same thing? Why is America and Great Britain and a few select countries here and there the only holdouts in a long dead Metric/Imperial war that is long dead pretty much everywhere else in the world?

Well the answer lies in Imperial Units’ other name – British Imperial, but it’s the “British” part that holds the key. While King Henry I is widely known as the person who tied the foot unit of measurement to a person’s own foot, there is a method to the British Imperial madness beyond parts of a person’s anatomy. All British Imperial units of measurement were first officially defined in the British Weights and Measures Act of 1824.

Of course, much like every law, this would not hold as there were still nominal variations from country to country. As our instruments for measurement improved, we found that our units of measurement simply did not hold up, so something had to be done. In 1959, the US, Canada, New Zealand, South Africa, Australia, and the UK all signed an international treaty known as the International Yard and Pound Agreement that finally standardized the weight and length of all nations. Finally, in 1959, we had all of today’s well-known deviations that you learn in grade school – 12 inches to a foot; 3 feet to a yard; 5,280 feet to a mile.

Still, something was lacking – these numbers made absolutely no sense. Why 12 inches to a foot? Why 3 feet to a yard? Meanwhile, the metric system was created in France in the late 18th Century and it had a simple base-10 system that was easy to remember, easy to multiply and easy to divide – 10 millimeters to a centimeter; 10 centimeters to a decimeter; 10 decimeters to a meter; 1,000 meters to a kilometer. Tens, hundreds, thousands, make sense; meanwhile threes, twelves, and 5,280’s certainly don’t.

America the free – from British and Metric Units

Thomas Jefferson identified this during his lifetime and even created another measurement system at the directive of the Treasury Department that mirrored the metric system in many ways. First of all, it was base-10, but still had many of the traditional names that Americans had grown accustomed to from the British system of measurement including inches, feet, bushels, ounces, and more. While the names were the same, the actual distance these covered were completely different from both the metric system and the British system.

Metric for the Win – Except in the United States

So while most of the world had adopted the metric system with its handy base-10 system in the 20th Century, the United States remains a holdout. That’s why Components for Industry continues to make components in both Imperial Units and Metric Units and that’s also why you’ll find both of these incongruent nuts, bolts, and other components on the same engines and other pieces of technology all of the time.

Sorry folks, that’s just how the world turns, and that’s just how the King wanted it nearly 200 years ago.


At CFI, we’re here to make sure that your parts are created to any standard – whether Metric or English and we’ll make sure that your parts are high-quality every time.

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