What size Air Compressor for Impact wrench - JeepForum.com
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post #1 of 9 Old 03-18-2009, 03:45 AM Thread Starter
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What size Air Compressor for Impact wrench

I have tried reading up on the many many different size air compressors that are out there. And the list and comments vary.

Has anyone used the Harbor Freight 3hp 21 gallon tank 120volt 125 PSI air compressor for an impact wrench and an air sander? Air delivery: 7.0 SCFM @ 40 PSI; 4.9 SCFM @ 90 PSI; 4.3 SCFM @ 115 PSI

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post #2 of 9 Old 03-18-2009, 07:53 AM
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assuming a 1/2" drive impact for removing tires and such I would say at an average operating pressure of 90PSI I'd say you need a compressor that can do at least 5.4scfm. Thats what is recommended on my old Matco impact and I think its pretty standard across the board. I didnt see a recommended pressure but I've always left my regulator set at 90psi... Hope that helps!

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post #3 of 9 Old 03-18-2009, 08:13 AM
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Originally Posted by Randy77358 View Post
I have tried reading up on the many many different size air compressors that are out there. And the list and comments vary.

Has anyone used the Harbor Freight 3hp 21 gallon tank 120volt 125 PSI air compressor for an impact wrench and an air sander? Air delivery: 7.0 SCFM @ 40 PSI; 4.9 SCFM @ 90 PSI; 4.3 SCFM @ 115 PSI
I actually have that exact copressor. Now its not bad but I would go bigger if I could do it again. It does great with a impact wrench. (Make sure you dont buy a HF one they suck! Except the earthquake series is ok) Now if you use a air sander you will have fits, the compressor will run constantly.

All in though its done awesome for all my paintings and its wicked easy to move and throw in the back of the truck. If you move it alot you will need to change the wheels and replace the rubber feet with blocks of wood. The stock support stuff wont last long! Good Luck!
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post #4 of 9 Old 03-18-2009, 07:56 PM
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I have a 30 gallon 5 hp which is barely adequate. I wouldn't go any smaller.

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post #5 of 9 Old 03-18-2009, 07:58 PM
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Sears has theres rated by a star method.If you go looking you will c what you need.
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post #6 of 9 Old 03-19-2009, 12:23 AM
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It isn't size, it is CFM. Make sure that you get the most CFM that you can afford.

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post #7 of 9 Old 06-12-2009, 11:40 AM
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Yes CFM is the key. If you look at most impact wrenchs for sale today it's anywhere between 4.0 and 5.0 cfm @90 psi depending on how heavy duty you get. The stronger the horsepower the heigher your cfm rating will be. I to notice the ones at harbor freight and am concerned with the life of it. They do offer an extended warrenty if I remember correctly that does not cost much and it's a replacement warrenty not a fix-it type one. I know Harbor Freight at one point sold the old Chicago Pneumatic line which back in the day was good quality. Not sure if it's the same thing now or not. If you got it let us know how it's working out.
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post #8 of 9 Old 06-12-2009, 11:59 AM
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if you are going to run a sander/buffer/D/A you will want a 2 stage. but those are super spendy. I have a 60 Cambel huasfeld(?) Single stage. it works good for most applications but some times i have to let it recharge and try again. even though its a 60 gallon it still wont keep up with a sander or a D/A, it wont even keep up with a 3/8 air ratchet. runs just as offten as a 30 gallon. so the tank size really doesnt matter all that much. as stated above, cfm is the key not the size of the tank. get one that is useful and easy to move around. Mine is wired 220 and weighs 200 lbs. I wish i had a 20 or 30 gallon 120 that i could move around and take places.
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post #9 of 9 Old 06-12-2009, 12:14 PM
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The impact isn't the issue, it's the sander.

Look at your air tools and see what CFM they require.
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