Matching air powered tools to Compressors

[Snagglefoot]

I had a look at some random air tools today and they seemed to spec out 2.7 to 3.0 CFM @90 psi.There a few wheeled compressors on sale that were 8 gallons and supposedly capable of delivering 3.5 to 4.0 CFM at 90 psi. Is this a case where the compressor’s rating is wishful thinking or do you think these compressors can run a single tool. Here are some of the tools and a couple of compressors.

 

[Snagglefoot]

And here are two of the compressors.

 

[ripcord]

A lot of those ratings are wishful thinking. Four CFM's at 90 psi is about as much as you'll ever really get out of the best 120v compressors on the market. A bigger tank just gives you a longer head start before you run out of pressure. Ignore the HP ratings because the manufacturers play word games with the HP ratings. Look at the amps the electric motor draws. Look for at least 15 amps and a quality oil filled pump.

That said, you can never have enough air, and I've never used a 120v compressor that I couldn't run out of air with air ratchets or impact wrenches so temper your expectations

 

[AutoMechanic]

In my opinion the bigger compressor the better. I have a 20 gallon at home have no idea the ratings on it but it’s powerful.

 

[sloinker]

You can never have too much air compressor. If you don't have to haul it around or have a specific small tool in mind, buy a IR/Quincy or another American made minimum 5HP 230V 60 gallon receiver and two stage. Anything less is just amateur hour.

 

[HangFire]

For decades I had an old 10 gallon tank, 1/3HP compressor. I rocked that for years with an inflator, blow gun, air hammer and air ratchet until 10 years ago got into air impacts. I found I had to replace some constrictive air fittings, then my impact started being useful. My 10gallon tank was (barely) enough to take all the lug nuts off my truck, if I was (very) judicious with the trigger. Then I had to wait for a refill.

Another plan was to take one side wheels off and run it down, then let it refill while moving wheels around, then do the other side.

If you want to get started in air tools on the cheap, my advice is to get as much tank as possible, with as big an oil lubricated compressor you can afford (or have an outlet for). If forced to choose, get the bigger tank. Do not trust the air fittings, particularly the air tank exhaust. Replace it with a Milton V.

 

[HangFire]

Is this a case where the compressor’s rating is wishful thinking or do you think these compressors can run a single tool.

Real air tools have realistic air requirements.

Department store air tools like that are rated on a fictional "duty cycle". In reality they usually take much more air than their rating (i.e., they are inefficient), and you are expected to use them only the "duty cycle" period of time, for example 15 seconds out of every minute. Or 10 seconds. Or maybe just 5.

 

[ripcord]

Also, craigslist and offerup are loaded with used air compressors all the time. Twin cylinder pumps are more efficient if you can find one.

 

[samven]

I read an article somewhere years ago that explained how they play games with the ratings. One of them was to give the CFM of the air being taken in to the compressor and not the CFM of the air after it was compressed. So 1 cuft of static air is only about .18 cuft of air at 90 psi.

 

[clinebarger]

Also, craigslist and offerup are loaded with used air compressors all the time. Twin cylinder pumps are more efficient if you can find one.

You mean 2-Stage? Not all 2 cylinder pumps are 2-Stage.

 

[ripcord]

You mean 2-Stage? Not all 2 cylinder pumps are 2-Stage.

Yep that's right, but even a single stage two cylinder pump is usually more efficient as the pump doesn't have to be spun as fast to pump the same volume of air.

 

[Snagglefoot]

Just for fun I connected my Ingersoll Rand Air hammer to a totally inadequate air compressor which was a 1/3 HP compressor with a two gallon tank capable of 0.7 SCFM at 90 psi. I needed to adjust the position of a wheel knuckle on a set of KYB struts. Guess what. I was able to do it. I ran the pressure up to 90 psi and found I was able to give the gun a 5 second burst where the pressure dropped from 90 psi to 80 psi. It took just over a minute to run back up to 90 psi. I was able to adjust the knuckles with less than two five second bursts each. Done.
In a pinch....... Here is the setup.

 

[HangFire]

Run the pressure up to 100PSI and get a shorter hose, and you'll get a bit more out of it.

Or just get a bigger tank.

 

[demarpaint]

Bigger is always better. If you have the room start doing your homework on 60 gallon compressors. For me it was one of the best tool investments I ever made.

 

[ssspencerjr]

I bought a Makita MAC5200 and an Ingersol Rand wrench/wratchet combo. I'll never give up this compressor. Never.

 

[ripcord]

I bought a Makita MAC5200 and an Ingersol Rand wrench/wratchet combo. I'll never give up this compressor. Never.

That seems like a very handy form factor for hauling around to job sites. Hmm... I've got a welder, a small air compressor and and spare hand truck.

 

[ssspencerjr]

That seems like a very handy form factor for hauling around to job sites. Hmm... I've got a welder, a small air compressor and and spare hand truck.

From 0 PSI to 140 PSI is a minute and 14 seconds. Absolutely amazing.

 

[ABN_CBT_ENGR]

Is this a case where the compressor’s rating is wishful thinking or do you think these compressors can run a single tool.

Need to read it carefully

First the rate published is "perfectly accurate" based on the pump displacement and RPM with the valve design at rated HP. That's measured literally at the high stage discharge. (not the device at the end of the line) This is also NOT taking into account any valve or inner cooler loss ( if so equipped)

From that point, you have to factor in all losses from belt slip, motor duty cycle/loss, friction losses from that point to your tool inlet. (that's not counting tank capacity which is basically bulk storage).

This certainly includes line size (ID) length, kinks and type of fittings too (and leaks)

So, depending on all of that you may need to upsize the compressor to get that requirement at the only place it matters- the coupler for the tool.

 

[JC1]

Just for fun I connected my Ingersoll Rand Air hammer to a totally inadequate air compressor which was a 1/3 HP compressor with a two gallon tank capable of 0.7 SCFM at 90 psi. I needed to adjust the position of a wheel knuckle on a set of KYB struts. Guess what. I was able to do it. I ran the pressure up to 90 psi and found I was able to give the gun a 5 second burst where the pressure dropped from 90 psi to 80 psi. It took just over a minute to run back up to 90 psi. I was able to adjust the knuckles with less than two five second bursts each. Done.
In a pinch....... Here is the setup.

View attachment 36074View attachment 36075

This setup is good If you need this in a pinch. If you had to do this day in and out you'd be looking for a 60 gallon compressor...

 

[Trav]

I bought a Makita MAC5200 and an Ingersol Rand wrench/wratchet combo. I'll never give up this compressor. Never.

Makita makes an excellent portable unit. If you don't have them already get high volume fittings The new Milton 5 in 1 and Prevost work great with V fittings.

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Milton S-1751 Safety Exhaust Coupler, 1/4" body, 1/4" MNPT - - Amazon.com

Milton S-1751 Safety Exhaust Coupler, 1/4" body, 1/4" MNPT - - Amazon.com

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These are Euro plugs aka V fittings and will work with either.

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