Need advice regarding the threads on the end of the crankshaft, past the woodruff key. When I took the flywheel off, the puller alone didn't work. I had to tap the puller with a hammer. Unfortunately the threads on the end of the crankshaft distorted because the end of the shaft mushroomed a little. What is the best method to clean the threads up? Die or another tool that works better? What size die will I need to clean them up if that's the best way. Thanks for all the help!