I'll look for the die this week and double check the thread. I basically ran the die down the screw like you would with a nut, but much slower and backed it off a lot to keep the cuttings cleaned out of the die. It seems to me the diameters of the two screws were not that far off from each other - otherwise I wouldn't have thought about doing it in the first place.

"The universal aptitude for ineptitude makes any human accomplishment an incredible miracle." John Stapp - "Stapp's Law"
"Klaatu barada nikto"