This all just cracks me up.... I get dizzy just reading this stuff. No matter what 'units' you use, it's accuracy that matters. The next time you are at Home Depot or Lowes (or the metric equivalent thereof) with some time to kill, go to the tool area and look at the measuring tools. Pick what looks like an accurate tape measure and start using it to check all the other tape measures, scales, squares, etc. There will be significant differences in the accuracy of the tools.

I do a lot of woodworking, and trying to do the eighth, sixteenths, etc. just wears me out too. I am going to try a tape measure calibrated in 100ths. I guess I could go metric, but by gosh I'm an American and I'm not going to let a bunch of foreigners tell me what to do!..... OK, in the interest of world peace, maybe I'll try metric as well.
Mike66, you English (or of that descent) screwed things up.

The standard gallon of the Unites States contains 231 cubic inches, or 8.3389 pounds avoirdupois of distilled water at its maximum density, and with the barometer close to 30 inches. This is almost exactly equivalent to a cylinder of seven inches in diameter and six inches in height, and is the same as the old English wine gallon. Why we did this I don't know as everyone knows the English make lousy wine. It was much later that New Zealand and Australia started shipping decent wine to America.

The beer gallon, now little used in the United States, contains 282 cubic inches. The English imperial gallon contains 10 pounds avoirdupois of distilled water at 62 deg of Fahrenheit, and barometer at 30 inches, equal to 277.274 cubic inches.

I guess this really means the English liked beer more than wine. In addition, they figured this out when the pubs closed at 11 PM. or is that 2300 hours? Whatever...

John
Maybe we should use thousandths? Or would that be like the metric system. 100's is standard in this country as is 1/16 or 1/8". Is 10 stones metric? A-B is good; what about 10(A-B), does all this matter? In reality we are not doing academics in the classroom but measuring something in the real world that may read 7.71235". The carpender usually is establishing a cut-off mark hence so many cut-off stops - take one measurement, many cuts. Familarity breeds exempt! What are you use to? Why try to shove it down everyone else's throat? The measurement is 13.1547 mm so we can easily divide or multiply by 10 - the measurement is 10.010" -- my nephew just passed a stone a fortnight ago!

I think John's beer/wine thing makes perfect sense! Great post! Or should I say, great discussion on the principals of measurement as a post is what you hitch your horse to. But I think the automobile was created to keep the price of horses down.