/forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gifWell, I'm not in the air tool repair business anymore, but when I was, we loved folks like you who kept us in business. /forums/images/graemlins/laugh.gif Every air impact wrench I know of produces its rated torque at 90 psi, and that's the maximum recommended air pressure, but you can certainly get more power if you can turn up the pressure. And they'll usually last quite awhile even then, but eventually they break. Warranty would not cover such a break if they knew you were running over 90 psi, but of course they usually won't know. /forums/images/graemlins/wink.gif On that model, it usually twists the spline off the front end of the rotor, with the next most common thing being broken hammers and/or hammer frame. I could usually fix whatever needed fixing for $40 to $75 parts and labor. So, I'm certainly not telling anyone not to turn up the air pressure. You just have to decide for yourself if the additional power is needed enough to be worth the repair bills, and sometimes it is. I know that many of my customers ran 175 psi compressors and just didn't complain when they had to pay the bill.
Excessive air pressure, moisture, and failure to properly lubricate air tools is the only thing that keeps the repairmen in business. /forums/images/graemlins/grin.gif
Naturally, you do need an adequate flow volume, so the 3/8" hose is a good idea, especially if you have very much distance for the air to travel (long hose). Most folks use quick couplers on those wrenches, and their quick couplers are only 1/4".