that is the u.s. we have been going to change to the metric system for 40 years now we just can't seem to push the final button. stubborn so and so's the lot of us.

Interesting "Why Doesn't the United States Use the Metric System?"
[theatlantic.com]

Appelbaum: Much of the world started moving to the metric system in the late nineteenth century. You've written that the United States didn't follow, because of “the humble screw thread.” For want of a screw, the metric system was lost?

Mihm: Many factors played a role in frustrating the adoption of the metric system in the United States. But much of the opposition from the 1870s onward came from the manufacturers of high-end machine tools. They had based their entire system—which encompassed everything from lathe machines to devices for cutting screw threads—on the inch. Retooling, they argued, was prohibitively expensive. They successfully blocked the adoption of the metric system in Congress on a number of occasions in the late 19th and 20th century.

Appelbaum: So the people blocking adoption of the metric system weren't backward-looking traditionalists, but cutting-edge industrialists?

Mihm: That's correct. While the anti-metric forces included outright cranks, including people who believed that the inch was a God-given unit of measurement, the most sophisticated and powerful opponents of the metric system were anything but cranks. They were engineers who built the industrial infrastructure of the United States. And their concerns, while self-interested, were not entirely off base. Whatever the drawbacks of the English units, the inch was divided in ways that made sense to the mechanics and machinists of the era: it was built around "2s" rather than "10s," with each inch subdivided in half and in half again—and so forth. This permitted various sizes of screw thread to have some logical correspondence to all the other increments. The same was true of the sizes of other small parts that were essential modern machinery.