The unit of measure was 16ths
not 12ths, now assuming that
25.4mm = 1" which I think is
correct 1/16" = 1.5875 mm
7 * 1.5875 = 11.1125
So then 8/16" or 1/2" =12.7mm
That would be why I can use a 13mm
wrench on a 1/2" bolt but a 12mm is
too loose on a 7/16" bolt
But it would be so much easier if we
just all used metric units instead of
this horrid mix of sizes
Wild