Most rolled ballscrews are only hardened for a small amount of thickness. I usually design the ends to take this into account and grind the ends, using a tool post grinder, through the hardened surface. Then it threads like normal steel. Starting with a minor diameter of .5, I would grind to .375 and then thread. If you don't have a tool post grinder, I have seen some use a 4" grinder and do it by hand to the softer steel. Sooner or later though you have to be able to put it through the spindle hole of a lathe. |