That's interesting. A measurement of 0.125" has an implied precision of +/- 0.0005", but what is the implied precision of 1/8"? I don't think you can say that the number 8 has an implied precision because it's not a measurement. In fact, I would say that, devoid of context, 1/8" and 0.125" are...
I have a John Deere JD110 ride-on mower with a Briggs and Stratton 330000 series engine. I have previously used the valve clearances in the B&S Operators Manual (here, p9), which says 0.005" - 0.007" for the exhaust valve:
However, I am now replacing the camshaft so I have consulted the B&S...