Hello elliot, there is a tig rod called D2, I believe you will find that this might work very well for repairing the small nicks or other imperfections on the greenlee knock-out cutters that you inquired about. Likely you would need to grind the excesses off with a dremel type tool, either with a stone or with a carbide cutter, as the deposits will be fairly hard after welding. The only draw-back here might be the minimum purchase amounts that some suppliers impose on you when you are buying these types of fillers. Good luck and regards, aevald