A placeholder for compressor info - looking for someone to help round this out.
Usual commercial advice:
Size: add up all the CFM requirements of the tools that will be on the compressor at one time and get 20% more "delivered" or "free" volume not "displaced" volume
EXAMPLE:
The photo on the right is of (what I think is) a homemade set-up - aquired it at an estate sale in 2005.
On top is a two stage Ingersol-Rand compressor specs say: 17.5cfm at 90 PSI (220V 15amp). It's sitting on a 60 gallon horizontal storage tank.
The air intake is modified (thanks to Sabah and Stuart Kendall) commercial truck filters and a couple of pizza pans. Noisy but it works.
The tank at 110PSI - (use a regulator at tool end) can run a Trow and Holden B & D air hammer all day, it just cycles every once in awhile. Also runs a polisher and again it cycles -- just more frequently. Die grinders it keeps up with, BUT big air grinders (from Boeing Surplus) - it barely keeps up with.