I picked up a new (to me) 1/2" impact wrench to use and I looked on it to see what was the recommended operating air pressure. There wasn't any. Actually, very few tools have any recommendations. Does anybody know of a guide or chart of air pressures?? How much pressure are you running for general usage on your line? Granted, shooting 1/4" staples don't require as much pressure as an impact wrench, but there should be some kind of guideline.