Sir:
Sorry if I confused you. The tennon length is .800
on the P-17, major thd. dia is 1.125 and minor dia is just how you want thread depth to match action threads. I made a mistake in my tool being old - Sorry, but I do know how to cut square threads - if you have somes "tricks" up your sleeve please let me know - I can always learn something.
Sorry for the misunderstanding - I'm an old fart!
Harry B.