Hi Gang:

I did this back in 1974. I was making an indexing holder for sharpening end mills with 12 stops, every 30°. I think the thread was 2"-24tpi threaded with a 3/8"-24 tap. Someone pointed out the geometry isn't perfect, the angle of the thread around the tap is 2° while the nut I was threading was 0.38°. The nut was steel and I was chasing the thread a few thou a pass so it worked fine. Remember when tapping a 3/8-24 hole the tap cuts the full thread in one pass. This would be a nice way to thread ring for camera lenses.
Take care, Carl.