Comment Re:stupid observation... (Score 5, Informative) 909
Note to mods: He's talking about the square socket drive (from, e.g. the ratchet handle), not the size of the socket wrenches themselves.
Just curious, are there any metric drive standards in Europe, and why haven't they found their way to the US?
They're already here because they are the same. They are 6.35mm (1/4"), 9.5mm (3/8"), and 12.7mm (1/2").
There would be absolutely no upside to fragmentation in this standard (the only point of which is interchangeability). If you think the point of the metric system is to have everything in some integer measurement, then you're converting for the wrong reason.