I have a 5.5cfm@90psi 26-gallon tank compressor and mistakenly bought an impact wrench that requires 6.2cfm@90psi. Oops. All of my other air tools are within the working range for this compressor, but I think that I can reasonably use the impact wrench in short bursts without any problem. It seems to me that starting with a full tank, the tool will bleed off air at a such a rate that before the compressor kicks on, I'll have finished what I'm doing. With the tool running continuously, a compressor that exceeds the tool requirements will replenish the tank pressure (however slowly), and then stop until the pressure drops and the compressor is needed again. However, one that is below the tool requirement will continue to run until the tank pressure falls below 90psi and then fail to supply the tool with sufficient air.

Does this make sense? If not, why not?