The machine shops that I'm familiar with (and all the drawings that I've dealt with) take inches and convert it to thousants of an inch.
I had to convert it so much that I have just about all the fractions to thousanths memorized. I even bought a couple of tape measures that read in inches and tenths of an inch, not 16ths.
Just using the decimal format. Some people get so frustrated if things don't work out to a fraction
If a tape measure is involved, then I go to the nearest 1/32" on the CAD files.
I've been known to scribe a line on a part with the tools, then toss it in the mill and split that line down the middle within a grand or so, without measuring. I don't think my peepers work that well anymore.
