The super-slow conversion of the U.S. to metric (2025)

Summary

While most other manufacturers in the world only have to deal with the centimeter side of the ruler, U.S. metal fabricators have to use both sides. mecaleha / DigitalVision Vectors / Getty Images PlusBack when I was a Catholic-school kid in northern Wisconsin, my school lessons briefly focused on the metric system. This was in the late 1970s. Along with learning cursive and the referents of rosary beads, we learned that the base-10 system would be critically important in all things science and engineering. This focus on metric stemmed from the Metric Conversion Act, passed in Congress in 1975, and the United States Metric Board that it created. Forward-thinking members of Congress and President Gerald Ford wanted us kids to join the rest of the world in thinking about distances in kilometers and weight in kilos. Signing the bill in December 1975, Ford argued that our continued use of U.S. customary (the more accurate name for what’s sometimes the called the British Imperial system) had created “an island in a metric sea.” But this well-intentioned legislation had a problem: It made the change to metric, in the words of the act, “completely voluntary.” So after a brief burst of attention to metric, many of us pretty much forgot about it, except when running a 10K or buying a 2-liter bottle of soda. President Ronald Reagan disbanded the Metric Board in 1982. But in reality, metric never really left. As Elizabeth Benham pointed out in her article for the National Institute of Standards and Technology, U.S. customary units have been defined in terms of metric units since 1893. And even though the progress has been slow, the U.S. has continued toward conversion, as Ross Rowlett described in his short history of metric in the U.S. Indeed, numerous manufacturers, including Caterpillar, Ingersoll-Rand, and General Motors, have adopted metric to facilitate their participation in the global economy. Now that I work at Howe’s Welding and Metal Fabrication, a small welding and ...