Tools, Sharpening and Power Machinery - Air tool question

Hi all,

I have a Campbell Hausfield impact wrench (http://************/r4cuzd) rated at ~500 ft-lbs of torque but requires something like 5.1 or 5.2 SCFM of air. I'm looking at getting either the Makita MAC2400 (4.2 SCFM) or the MAC5200 (6.1 SCFM). My question is, do I need to get the MAC5200 because it exceeds the airflow rating of the wrench, or will the MAC2400 be satisfactory for most tasks? All I really use the wrench for is 4 tire changes a year, so nothing major like suspension work or autobody repair.

Welcome to the forums! In reality, neither will do a great job with an impact wrench. An impact wrench uses an inordinate amount of air to operate. It is not particularly the cfm nor the max pressure but VOLUME of the tank. For mechanical tools it is best to buy a larger, say 26 gallon tank unit. I know you said it won't be used that much, and the larger Makita may do the job in short spurts, but more use would require a larger compressor.

Hello bigbadandugly and welcome to our forums!
Chandler is right on in that neither of those compressors would do a "good" job with an air wrench.

There are a couple of different trains of thought on the size of the air tank though.
The main purpose of the air storage tank is to prevent the compressor from cycling on and off when a small amount of air is being used.
At one time the size of the tank pretty much was determined by the capacity of the compressor unit.
Now it seems air tank size is being used as a sales tool.

What determines how well a compressor is matched to a tool is its CFM capacity.
It is true that a larger tank will store more air but when that air is depleted the air delivered by the pump is what is used to operate the tool.
The problem with using a larger tank on a small compressor is that you will only have a few seconds of air reserve before the compressor kicks in and the pressure drops to the unuseable level.
This is where you will have to decide on how long you want to wait for the tank to build up.
A larger tank is always better as said but it has to have a pump that can meet the demand.

I would assume that you are buying a compressor to plug into a 120 volt 15 amp circuit and if so the largest capacity compressor you can generally run on this circuit is 6 cfm@ 100 psi.

More compressor info here (http://http://forum.doityourself.com/tools-sharpening-power-machinery/131654-air-compressor-information.html).

(If you want to provide a link to your tool you can not use a url shortcut if that is why your link is blocked out.)

Thanks for that. It was extremely helpful. What I liked about the MAC5200 was the small tank but powerful compressor, allowing me to conveniently store it in my garage. So right now I have a CH 5-HP, 13 Gallon 5.5 SCFM oilless compressor that I'm about to sell because I read that oiled compressors are more reliable long-term and quite a bit quieter. My plan was to "upgrade" to a new MAC5200 because there is a good sale on now.

So given my infrequent impact wrench use (2 tire changes per vehicle annually, 2 vehicles in family) and perhaps to drive a spray paint gun for a 1,100 sq. ft store renovation (I can suffer a bit of a PITA waiting for the tank to refill given it is a one-time use), should I upgrade to the MAC5200 or stick with my current CH?

If tank size is such a significant factor for many uses, why do the make 5-gallon compressors with big compressors like the MAC5200? From what you guys are saying, it seems like a 5 gallon compressor is really only good for nailers.

bigbadandugly

Did you read the link I posted?
There it explains a bit about oiled compressors but I'll repeat what it says.
Yes, an oiled compressor generally is more reliable than an oilless type but this does not always apply to direct drive oiled types.
What are generally seen as a reliable compressor type are the belt drive type.

Having said that Makita is a very reliable manufacturer and I am sure you would be very happy with that one.

I have several different types of air compressor but my favorite is a Porter Cable oilless type.
It's a bit heavy to lug around but delivers plenty of air and is very quiet for an oilless type.

http://www.deltaportercable.com//ProductImages/PC_Graphics/PHOTOS/PORTER-CABLE/TOOLS/MEDIUM/3/C3101_1.gif
Image courtesy of deltaportercable.com

I think the difference with mine and one like the Makita is that they are better built than the less expensive models that seem to be very popular.

As far as tank size goes there are many beliefs on that one so I won't really say too much except to say that the main purpose of an air tank is to prevent the compressor from going on/off too much when air use is light or intermittant.
Yes, there is a small amount of air stored that might give an air wrench for instance a few more seconds of full power before the tank goes flat.
I guess this would be an added bonus for folks with a compressor smaller than a tool requires.

Just adding fuel to the fire, I use a double hot dog Ridgid, which gives me alot of air, because we may be running more than one gun from it. I especially like the wheels and handle that make for easy transport on a jobsite.
You may be able to get enough out of the double hot dog to loosen a few lug nuts, but continuous use is out of the question.

Larry