Your right, I made a Oops. H1 is .0005; H2 is .001, etc. In .0005 increments.Roger, you know squat about threading dimensions.
H numbers are .0005 increments, not .001. Higher H numbers are usually used when heat treating and plating, not for final fit.
Pitch diameter of the male threads is the typical determining dimension.
Class 1A, 2A, 3A are the usual fits. 2A is the most common. 1A can be very loose and 3A has a tighter tolerance.
Example:3/4-10 pitch diameter.
1A .6744 to .6831
2A .6773 to .6832
3A .6806 to .6850