CNC Lathe Threading, Again

I didn't express my concern correctly in my 1st post.
Let me try again.
When I convert my machine to CNC, and I want to do threading, how do I
pick up the same position of the tooland
the rotation angle of the chuck so that the tool follows the same cut
path as the first cut?

Could be I can't see the forrest because of the trees. Would you all
try again so that I can get it straight?

Thank you.

Wally6800