Rick, That is EXACTLY what I have been saying. I did not mean those guys at the mine were doing the right thing and I have warned repeatedly about the folly of overpressure but some people just will not listen. I see it all the time, someone will come into the shop and say "my compressor will not keep up with my 1" drive impact how much will you charge for a bigger TANK!" or "do you have a regulator that will allow me to run 200 lbs"
. It seems too many people want to believe that more STORAGE translates into more compressor CFM and I have trouble making them understand that storage will not make up for insufficient pump CFM. In this case we were discussing extra tank pressure being used as extra tank volume not extra pressure at the tool and my point is that TANK volume no matter how it is obtained is not going to make up for a compressor that is too small, at least not after running more than one recharge cycle. If the pump CFM is low it is a small compressor and will perform like a small compressor even if you do up the pressure or add extra tanks. As for running 150 PSI on large tools like 1" drive impacts that much pressure will make a difference just not as much as most want to believe but running that high above the recommended pressure is common practice here,right or wrong, has been for years and I assume it will remain so. The efficiency drops off dramatically above a tool's designed operating pressure so a huge increase in pressure only amounts to a small increase in performance but this is often enough to make it worth it to some so as I said they will continue to do this. Also 175 PSI cut-off pressure is commonly found,from the factory, on two stage compressors with 60-80 gal tanks and 15-20 CFM range that are sold for small shops although some are less than that and I think what started this discussion was if raising the designed cut-off pressure would be beneficial or not and I think that at this point everyone understands that volume and pressure are two different things but getting more VOLUME to run tools was the original subject not more pressure at the tool. I don't see where anyone even suguested running more pressure at the tool and the examples I gave were to show how common it is for some to misunderstand the problem and the extremes they will go to.