Air powered die grinder, drill, or impact gun. Or, if it sounds real choppy, maybe an AC TIG welder. I’d bet die grinder. They’re not used all the time, and th

Air powered die grinder, drill, or impact gun. Or, if it sounds real choppy, maybe an AC TIG welder. I’d bet die grinder. They’re not used all the time, and they have VERY high rpm sounds which are always terrible.