Hi Gang:
I made my thread samples like this:
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It's just a bit of plywood with Imperial and Metric screws stuck in. All the Imperial threads are course so if the nut doesn't fit the metric screw or the NC screw, it might be NF. Metric is the top row.

I really like the formula for metric tap drills: M6 x 1 tap drill is 6-1=Ř5 drill. Also I once was told 70% thread takes way more force than 60%, but is hardly any stronger. So save your arm and taps and tap at a lower percentage!
Carl.