Is there any general correlation between bearing dots per square inch and a quantification of flatness? I ask this because once a piece goes flatter than the resolution of the dial indicator you are using (or for one's patience to jack a piece level) other methods (like optical flats, I suppose) must be used.
Could any kind of general conclusion about the flatness be assigned to the following ranges (like for example .001, .0001, 50 mils, 10 mils, respectively, or something else):
1) 5-8 spots / sq in 2) 15-20 3) 35-50 4) 100Thanks in advance for any insights or opinions.