If you are going to run air tools you'll want a compressor capable of maintaining the CFM required for your largest air consuming tool, without having the compressor running constantly. For instance, a sander, grinder, or an air wrench will need around 60-70 CFM at 90 to 120 psi. For me, that translates to a 80 to 150 gallon of capacity, a two stage compressor and at least a 7 hp 220 motor. My tank is an 80 gallon and, I don't run out of air but, I only use one air tool at a time. If I had a two man shop, I'd probably need an auxiliary air tank.
'The true soldier fights not because he hates what is in front of him, but because he loves what is behind him.' G. K. Chesterton
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