Small Compressor

That all depends on what kinds of tools you are running and under what conditions. Check the CFM usage of the tools you are going to use. Some general samples:

1/2" LD impact - 4 CFM @ 90 PSI 1/2" HD impact - 5.5 CFM @ 90 PSI 3/8" ratchet - 4 CFM @ 90 PSI Angle Grinder 7 CFM @ 90 PSI

This is truly the MINIMUM spec for running say a 'light' duty 1/2" ratchet and while in use, the compressor surely would be running all the time (not good for the compressor).

The minimum I would SUGGEST would be 3 HP, 150 PSI, 15 gal tank with more always being better.

If you're fairly handy, there's always the option of converting an A/C compressor to an air compressor.

Consider this:

-Tim

That would be just fine for running light loads and intermittent heavy loads. Don't expect to paint with it or to run a cut-off wheel or other continuous heavy load. But you could run power ratchets, butterfly wrenches, and even big impact wrenches for changing tires, as well as air up tires and run power nailers or staplers.

But note that those ratchet numbers are for CONTINUOUS use- you can easily zing off lug nuts using the reserve in the tank to supply more air than the compressor output for the brief amount of time needed for wrenching.

The only task I've ever done with an impact wrench that came remotely close to needing the full rated sustained air demand of the wrench is removing rear-axle U-bolt nuts (interference type). The angle grinder, on the other hand, takes every bit of its rating to do any useful work because you are always running it continuously rather than in bursts.

I got by with a 4.5 SCFM@90PSI 11 gallon compressor for YEARS running

1/2" HD impacts, 3/8" butterfly impacts, and so on, but it was impossible to use a grinder, polisher, or cut-off wheel with it. In fact I still grab that compressor when I need portability because my 5-horse 30-gallon is just too darned big. Its allegedly "portable" but in reality stays put in the garage next to its 220V outlet.

I'll admit, I've never seen a 2 HP 4 Gallon put out 4.2 CFM @ 90 PSI.

I am aware of that.

4.5 HP 11 gallon is quite a bit different than a 2 HP 4 Gallon.

I doubt he would even get any useful work out of an impact wrench. Even with my IR 2131, it would consume and deplete that built up pressure in a 4 gal tank in no time. Not enough reserve. If he were to use a cheap impact wrench (everything else on the market) he's going to be frustrated.

Dave >saeeng>Application, application, application. You can to an amazing amount of

Thanks for all your replies, I think I'll buy the small one for $85 and learn the hard way.

John

If you find you need more reserve, you can add an external auxiliary tank "T'd" in with your tool's air line, too.

I view adding air power the same way I view building a tool collection. Plan ahead, start out with something that you can build on later. It takes $$$ to buy the compressor AND the tools, and by starting with the small compressor you can put more $$ into quality tools that you can still use later when you can trade up to a bigger compressor.

|I view adding air power the same way I view building a tool collection. |Plan ahead, start out with something that you can build on later. It |takes $$$ to buy the compressor AND the tools, and by starting with the |small compressor you can put more $$ into quality tools that you can |still use later when you can trade up to a bigger compressor.

....and any compressor is better than NO compressor.

Agreed