Check out most any machining distributers like KBC, MSC & the local reps. They all tend to carry the same names. Starrett & Mitutoyo nice but are spendy. There are other good brands too for less $.
http://www.kbctools.ca/ for example, type in PN 1-804-482 & see if that style works
There is some code that describes the scale type. There are probably more I'mmissing but this gives you an idea.
4R: 8ths, 16ths, 32nds & 64ths
5R: 32nds, 64ths, 10ths & 100ths
16R: 32nds, 64ths, 50ths & 100ths
3R: 32nds, 64ths, 10ths & 50ths
Drafting scales are typically architectural. Oh, and they went CAD about 25 years ago