Have been using this cutting oil for almost ten years. I'm on my third bottle. I use it for tapping, tapping, driving 3-blade self-tapping screws, lubricating the Green Lee punch, and drilling mild steel, stainless steel, copper, and aluminum. This helps extend the life of taps and dies, as well as drill bits. Everyone knows how frustrating it is to break a tap on the very last hole you threaded. A little dub goes a long way.