Dave:
The best way is to go to your favorite chrome plater and have him dip just the thread section into the acid bath. Generally the plater will use sulpheric acid to do this. Have them be very carefull when they are doing this. The plater should use ONLY the amount of time to stripped the chrome as not to get to the metal tubing. I have had this done and they usually like to leave just a tiny bit of nickle plate left as not to damage the tube. your thread cutter ought to be able to cut through the last part of the nickle plate. One must remember what's most important...Your thread cutter or your frame? I think you know the anwser.
Good luck Jack (Giacomo) (Fulltime Architect, Part time wrench)Gabus Laguna Beach, CA jack@shermangabus.com