I am sorry, I meant to say boxes instead of tops... brain fart, getting old, lol. Thinking about some type of threading jig that many of the jig makers on site might build. Thank you
I would recommend tracking down a video called CHASING THREADS by Allan Batty. It is exactly all about this. I believe that CSUSA sells the chasing tools.
I rented the video from a technical online video rental store. Don't remember the link though.