Hi Barry,
What you are refering to is what the machining industry calls the "H Limit" or the "L Limit"....

You'll find it as a number system for taps and dies like, H1-H7 or L1-L7 etc......

They reference a tolerance value... So aerospace needs high tolerances. Home depot stuff wiggles around on each other before it's tightend...

It's basically/simply achieved by the depth of the thread cutting tool..

so to make workable nuts and bolts, you will need a "3rd object generated" which will be the tap or the die, to boolean the threads, to work with the current "M12 Bolt" etc....

I dont know enough to be able to just give you the numbers... A Machinsts Handbook can, or asking in a CNC forum also...