10mm=0.394" 3/8"=0.375", difference of 0.019" 7/16"=0.4375", difference of 0.0435" 7/16 is much closer to 11mm which is 0.43307", a difference of 0.00443"
Yay. By my math, we got a bit over 140 tons of rain on the homestead today. That sounds like a lot more than the more common way to express a quarter of an inch of precipitation.
I wasn't going for closeness of size I was going by memory of which sizes were most often used on the Fords, Chevys, Pontiacs, etc., that I did a lot of wrenching on when I was a teenager. Back then it seemed like a 9/16, 1/2 and 7/16 was pretty much all you needed to do a complete teardown on a Pontiac 400 cubic inch V8.
Like many of us in life, we learn from our mistakes, and fortunately your mistake didn’t cost you anything.
I agree, almost looks like someone dropped it when moving it with a sit down forklift. Had an employee do that with a smaller reach.