If you need to cut the tread with a die make a holder from a piece of cold rolled steel. Turn one end down to fit a drill chuck (at least 1/2 inch dia) and drill and bore the front end 3/4 dia somewhat deeper than your 5/8 thread is long. Bore out the front part to the size of your die and add a set screw to hold the die. You can make a holder for different dies like 13/16 dia or 1" or metric sizes. Comes in handy. Juergenwt.