Thanks for sharing your detailed explanation, Using the compound slide set parallel to the lathe’s axis is brilliant and your tips to align and synchronize the tool path with the existing thread are the key to success. As Darren indicates, this is not a simple lathe project, it requires a great deal of experience. It is one thing to cut treads on a blank shaft and another entirely to re-cut an existing thread.
Just a follow up, I was able to repair the feedscrew successfully with the die which was loaned to me. No more clicking and skipping.
I had to chase the entire screw, it have several lengthy spots where the threads had been mashed.
Many thanks to the generous and helpful folks on this board.
Wes