Home air compressor question:

[speeder]

A recent thread got me interested in learning more about compressors. I have an extra small one that I was about to sell on CL when I realized that it might have more guts than the one I use. Both are 110V.

Here is mine:

Here is the extra one to sell. It has a much smaller tank, (13 gallon vs. 22), but it has 4hp vs. 3hp. Which is better? My bigger tank one works OK for what I use it for. Thanks.

[Zeke]

I'll always take a belt driven one over a direct drive. HP ratings mean nothing to me any more because years ago you wouldn't have had a chance of running a 5 HP on 120v. Nowadays, they'd have you believe that is 5 real HP. CFM is what to look for.

For what compressors sell for on CL, you might keep the 2nd one for a back up. I had 5, I'm now down to 4.

[masraum]

does that sticker on the CH have 2 or 3 cfm ratings? When I was researching, it seemed like the numbers to look at were the cfm ratings, and most home style compressors will do about 150psi, so the ratings will look something like

SCFM Delivery At 40 psi: 3.7 SCFM
SCFM Delivery At 90 psi: 2.4 SCFM

You want higher numbers. Look at the tools that you use, and make sure that the compressor will support them.

[on2wheels52]

"I'll always take a belt driven one over a direct drive."

+1
Real compressors have a belt.
Jim

[Head416]

What is the benefit of belt-drive?

[Zeke]

It's quieter and should be more powerful in displacement, but I can't say that for sure because the direct drives really spin the pump and therefore should achieve a high rate of charge.
I just like an old 2 lunger that runs slower and lasts longer. The motor to pump ratio is like 3:1 or 4:1. The 2 lunger can be a dual piston single or 2 stage for higher pressures. I have never had a 2 stage. I look for cast irons pumps, too.

[speeder]

So the one I'm already using is better, right?

Mine is 8.6 SCFM @ 40 psi and the other I cannot read on this sticker...

I'll have to get a better look tomorrow. (This is from the smaller one):

[aigel]

Which one runs the highest pressure? Sounds to me like you could use that for your impact (from the harmonic balancer thread). CFM are important on grinders, sanders but not for impact or even air ratchets.

George

[911pcars]

Can you confirm a 110VAC home unit will produce 150 psi?

That pressure gets close to the output from a two-stage compressor.

Sherwood

[aigel]

I get about 125 on my single stage cheapo oiled unit from Costco.

George

[Zeke]

Originally Posted by 911pcars

Can you confirm a 110VAC home unit will produce 150 psi?

That pressure gets close to the output from a two-stage compressor.

Sherwood

They are going higher these days. I doubt 150 is anywhere near a standard. I'm happy at 120.

[Joe Ricard]

I have 2 compressors, one direct and one belt. I use the belt most often it has 10cfm the direct is 3.4

When I really need lots of air I connect both of them together to one out put hose. Air cut off wheels run wide open all day without running out of air. Impact wrenches have all the grunt to loosen anything.

CFM rules. (like torque). Pressure is what sells (like Horsepower)

[Zeke]

I've done the 2 compressors thing. It's good to have a couple of one way check valves as one compressor always runs harder.