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Hi all. Last Christmas my dad bought me this Craftsmen tire care kit that included a 1/2″ impact. I had been saying how I want a bigger air compressor and air tools. Last summer, I did use the impact once with my 3 gallon compressor. It was just enough to remove a nut from a pulley on the lawn mower. I also used it to put it back on. About 2 months ago, I bought a nice big 21 gallon compressor and 50′ 3/8″ hose from Harbor Freight. I know it’s not the best brand, but I’m not running a shop, just my hobby stuff. Last weekend, I sat down to do my brakes and busted out the impact. I found that at 120 PSI, the impact would not even come close to loosening the lug nuts. I broke them loose with a 4-way wrench with little effort. Without any load the impact spun fast and free. But I could hold it in my hand with little effort and that would stop it from spinning. The socket did jerk back and forth with the hammer inside, but it had not inclination to rotate.
After reading my little manual that came with the impact gun, I found three possible causes:
1) The hose is too long. 25′ is the recommended length.
2) Not enough oil in the air inlet. I put in two drops to start, but added a few more for good measure. It didn’t help.
3) Not enough oil in the hammer. I added maybe a 1/4 ounce of oil in it, still no help.The only thing I can’t try is the hose. I only have the one large hose. I did swap back to the 1/4 hose that I used last summer on my 3 gallon compressor. That compressor and hose was enough to loosen a bolt before, but that hose with the new 21 gallon compressor didn’t make a difference. The only thing I didn’t try was busting out the old 3 gallon. I didn’t do that because I’d wasted a lot of time already and needed to get to my break job.
So what I’m looking for is some suggestions of what to look for. I can’t verify that my new compressor is good as this is the only air tool I have. I can buy another hose, to test with, but it seems odd that it worked last summer with a little 1/4 plastic hose. Any ideas?
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I have opened the regulator to 125 PSI, but I don’t have a way to independently verify that. I’m not sure that is does put out the full 4.7 CFM, but I’m only 800 feet above sea level. If I recall right, the testing is done or calculated at sea level. I wouldn’t expect a huge change. And like you say, with a 21 gallon tank, I should get *something* out of it.
I think I’m going to try and talk to a manager there. I bought the service plan, and I’d be happy to return it for store credit. I wanted this one in the first place, but the price really put me off.
http://www.harborfreight.com/2-horsepower-29-gallon-150-psi-cast-iron-vertical-air-compressor-68127-8026.html#pr-header-68127Strangely, rated for less HP.
Hi Buggsy!
I see you’ve had almost an exact replica of my experience with an impact.
here’s a link to my detailed description of it
In essence everyone I spoke to kept telling me it was the too small compressor , but in the end , after changing hose/connectors/chucks/adapters/whatever nothing changed and I too could stop the impact with my hand and not much effort.
In my case too the impact did blow a lot of air with no apparent movement of the bit. :SSo I changed the impact with an IR one, and not the compressor, and it made a HUGE difference, just like from night to day! 🙂
And not only it *has the power* but it does use a very limited amount of air to do that, I can take off 5-6 lugnuts and the compressor (6 gallons) still does not start up.
Trust me, from what you tell you’re in the same situation there.
Get a nice good IR clone (or an IR if you can afford it) like someone suggested before and be happy with it and its results! 😉
Happy impacting! :cheer:
Live long and prosper (and stay dirty!)
10nico
[quote=”10nico” post=47626]Get a nice good IR clone (or an IR if you can afford it) like someone suggested before and be happy with it and its results! 😉 [/quote]
I would really like to see you verify that it is either the impact or the compressor before making any further investments. You can confirm the pressure coming out if you got a pressure gauge and put a quick connect fitting in it.
Thanks. I do have a spare gauge, just no female quick connects. I’m pretty sure I’ll see my father-in-law this weekend as it’s his birthday. I’ll bring my impact and give it a try there. I was thinking about just buying another ho-hum, average impact from HF and trying it. I can always return it if it doesn’t work out. I might even just order an Earthquake and try to return this Craftsmen for store credit.
Look up the CFM rating for your compressor. Then look up the CFM required for your air tools. The compressor’s CFM rating is probably too low for the tools. I had the exact same issue. I returned the whole thing. CFM stands for Cubic Feet Per Minute. An impact wrench sucks a lot of air, so the PSI is useless unless the air can be replaced quick enough. PSI is only one way to measure the power of an air compressor. Go to this website to get some advice on how to buy one of these.
I upgraded to this one BTW:
http://www.aircompressorsdirect.com/Chicago-Pneumatic-RCP-226VP-Air-Compressor/p2041.html
[quote=”matthewross1987″ post=47691]Look up the CFM rating for your compressor. Then look up the CFM required for your air tools. The compressor’s CFM rating is probably too low for the tools.[/quote]
His compressor is rated at 4.7 CFM @ 90psi, Mine is only rated for 4 @ 90 (I looked it up today). I can run air tools all day off of mine, no problem. I get amazing airflow and never run out of air for my impacts, even “Big Bertha”. My air compressor actually keeps up with my Die Grinders too. I think the problem either lies with the compressor not putting out its rated power, or the Impact just sucks.
Definitely could be caused by those reasons. I guess it depends on the exact specs your working with. I know personally that mine was just underpowered. But then again, I had a 3.8 cfm compressor and the impact needed 5.5. So the difference was more noticeable. His problem could definitely be caused by what you mentioned.
That, and cheaper air compressors put out less air than similar-rated commercial compressors, and cheep air tools use more air than similar rated pro air tools. I would bet on it being the impact, but I dont want Buggsy to go out and buy a $100 impact if its not going to work. Call up your local tool dealer, Have him stop by and let you try one of his loaners 😛
There is no CFM requirements listed for the impact, unfortunately.
This is what I got as a gift.
http://www.sears.com/craftsman-6-piece-tire-maintenance-kit/p-00916861000P?prdNo=1&blockNo=1&blockType=G1As best I can compare, it’s likely this impact gun:
http://www.sears.com/craftsman-1-2in-impact-wrench/p-00916882000P?prdNo=7&blockNo=7&blockType=G7
Which lists air consumption at 5.2 CFM. Pretty close really.Now here is the kicker. Going back to what I said a while ago in this tread, it works better with my little 3 gallon, 2.4 CFM compressor (http://www.sears.com/craftsman-3-gallon-horizontal-air-compressor-with-hose/p-00915310000P?prdNo=2&blockNo=2&blockType=G2) than the giant 21 gallon tank. Compressor not withstanding, the tank alone should give me what I need. Honestly, I had forgotten about the 3 gallon compressor test I did a while ago until last night. I repeated my test and while I can hold it still with my hand, it hurts. It’s trying a lot harder to turn and the impact part is far more forceful. It can only run it for 2 seconds before I drop below the 90 PSI mark. I don’t remember why I decided it was the tool before, but I’m pretty sure now it’s the tank. Something must be constricting the air flow.
[quote=”Buggsy” post=47743]There is no CFM requirements listed for the impact, unfortunately.
This is what I got as a gift.
http://www.sears.com/craftsman-6-piece-tire-maintenance-kit/p-00916861000P?prdNo=1&blockNo=1&blockType=G1As best I can compare, it’s likely this impact gun:
http://www.sears.com/craftsman-1-2in-impact-wrench/p-00916882000P?prdNo=7&blockNo=7&blockType=G7
Which lists air consumption at 5.2 CFM. Pretty close really.
[/quote]Hi again!
I see your impact does indeed seem to be a clone of something respectable, much more than my “toy-impact”, which is this one:
My weak impact is this and just by looking at it , you can understand its flimsyness.
Now here is the kicker. Going back to what I said a while ago in this tread, it works better with my little 3 gallon, 2.4 CFM compressor (http://www.sears.com/craftsman-3-gallon-horizontal-air-compressor-with-hose/p-00915310000P?prdNo=2&blockNo=2&blockType=G2) than the giant 21 gallon tank. Compressor not withstanding, the tank alone should give me what I need. Honestly, I had forgotten about the 3 gallon compressor test I did a while ago until last night. I repeated my test and while I can hold it still with my hand, it hurts. It’s trying a lot harder to turn and the impact part is far more forceful. It can only run it for 2 seconds before I drop below the 90 PSI mark. I don’t remember why I decided it was the tool before, but I’m pretty sure now it’s the tank. Something must be constricting the air flow.
This is interesting, it just sounds like the pressure regulator on the 21 gallons tank is defective or at least does indeed heavily limit the air flow.
I’d try to bypass the regulator and get the full tank pressure (and full airflow);In my “el cheapo” 6 gallon tank I actually have two outlets, one is after the regulator, and one is before, and by using this I can bypass the regulator and get the full flow.
In some other compressors I’ve seen people unscrew the safety valve and put a T shaped adapter, on one end of the T they’ve put a quick connect outlet and on the other they’ve put the safety valve.
In any case, it’s really evident that a 21 gallon tank simply cannot do worse than a 3 gallon tank!!
So if it’s not the tank itself, it has to be the regulator or the metal tubing to it or the outlet coupler which drastically restrict the airflow in some way.Also I can confirm two other things:
1) in the compressor specs when they put the CFM rating, they refer to the continuous or sustained air flow the pump (electric motor + piston/whatever) can push into the tank.
The actual airflow of the tank is much higher, but for a very short period of time, and it’s indeed limited by the internal diameter of all the parts *after* the tank (metal tubes, flow regulator, outlet couplers…).
Usually a low grade compressor also has low grade parts which in turn contribute to limit its maximum airflow.
2) the specs are usually “inflated” (no pun intended! 😆 ) especially on cheap/no brand unitsStill, if a 21 gal tank is inflated at (say) 125 psi and gets a direct connection to the air hose+impact it will indeed do a hell of a flow, if just for some ten seconds.
Mine does, and it’s only 6 gallons (and cheap).
So, check if you can bypass the regulator and try again!
Good luck! 😉
Live long and prosper ( and stay dirty! )
10nico
Ah, and one more thing:
A good quality impact does have a higher efficiency converting air flow/pressure into torque, and in fact a good quality impact does require LESS air to do MORE torque.
Conversely a low quality impact does have a lower efficiency and requires MORE air to do LESS torque.
I know this air-torque conversion is exactly proportional to the internal structure of the impact, but I know for sure that (for example) to get more efficiency in its top rated models, IR uses more vanes (7 instead of 6 of its other models) into the mechaninsm and also uses lighter metals (titanium) for the moving parts, and also a “dual hammer” mechanism as opposed to the “classic-old style) “single hammer” mechanisms.
Maybe someone with better understanding of physics of the fluids could explain why this works better…sorry! 😛
Live long and prosper (and stay dirty!)
10nico
I took a look at it on my way to work. The regulator is just a short nipple away from the pressure switch. I should be able to unscrew it and thread a coupler straight on the tank. Well, right to the pressure switch. If that fails, I’d have to tee off under the pressure switch to make sure I get full tank volume.
Before I get into it though, I want to call the store and see if that will void my warranty. I don’t want to do this, then get told I tampered with it and can’t get any help.
If your air compressor cannot maintain the psi and provide the proper CFM (Cubic Feet of air per Minute) output that your air tool requires to operate it properly, it will NOT operate properly. Every tool requires a certain amount of pressure (PSI) and there must be a certain amount of airflow (CFM) to propel the vanes in the tool to spin. If after 2 seconds of using the tool the air pressure from the compressor drops below what is required by the tool to operate as designed the tool will loose all its capability to operate as it should. Operation of the tool with more pressure (PSI) than it was designed to use will ruin the tool as with not having the proper oil in the tool to lubricate it as it should be. The regulator is there to set the output pressure to the operating pressure of the tool. Setting the output pressure to more than required WILL NOT increase the power of the tool!
You will only shorten the life of the tool! The higher you set the pressure the lower your output SCFM to the tool will be, so setting higher PSI means lower air flow to the tool. My compressor delivers 8.6 SCFM @ 40 PSI and 6.4 SCFM @ 90 PSI as an example (Craftsman 919.167312)
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