Impact driver / compressor compatibility

[N2ae86]

Hi guys,

Before I spend some money I just wanted to check that I am not going to make an expensive mistake. So I need your collective wisdom and advice!


I am after a new Impact Driver - and have decided on the Chicago Pneumatic CP7748.

http://www.toolstop.co.uk/chicago-pneumatic-cp7748-1-2-inch-impact-wrench-p71515

However I am concerned that the gun won't have the guts to do the job because of my compressor.

Its one of these:

https://www.machinemart.co.uk/shop/product/details/airmaster-tiger-14-60-air-compressor

14CFM, 3Hp, 8 Bar etc.

The tool will be powered straight from the tank - 1/2 ball valve - 3/8's hose - 1/4 fittings.


Now the big question is will I be providing enough air to the gun to allow it to run to its full ability or is it going to struggle due to the limitations of my compressor?

I just want something that will blast off stubborn suspension bolts / crank pulley bolts - at the moment my Clarke impact driver struggles with anything thats on more than finger tight.

Thanks

James

 

[brightspark]

just check the spec on all the diffrent models. higher the better

 

[wristpin]

Not an expert in these things but the spec sheet for the gun says "Actual air consumption: 12 l/s / 25 cfm" whereas the compressor is rated at 14cfm and I think even that is capacity and not free air delivered ie actual output. So would guess that the compressor would run out of puff with that gun but someone else may know different!

 

[Rig Pig]

If you're only using it for short bursts then it should be fine as the tank will feed the gun.

 

[blenkie1]

Cordless impact guns are the things to have. The bigger ones by snap on and the like are absolutely brilliant, big money though. I have an ex demo metabo 600nm for around £130, already had the batteries. What a great timesaver. Done away with the ratchet!

 

[J.F]

I made the same mistake, a 50L compressor is not enough. I think that the 25cfm is a duty cycle of if you use the wrench for X seconds in a minute. If you tried to use it for 1 minute contiuous it would be more than 25cfm. I think you need a 150 -200l comp at 10bar to run a gun like that at full power continuous. In the end i got another second hand 50L tank and linked them together. And used 1/2" bore hose from the tank and used a pcl conector with 1/2" bore tail to the 1/4" pcl fitting for the wrench. And don't regulate the 8bar down to 90psi as 10m of hose will drop the pressue anyway. So with 100l combined and 1/2" of 10m hose straight to the a similar spec wrench unregulated i get approx 6-7 seconds at FULL power which is ok for me doing diy car repaires.

 

[normspanners]

Well I can run my snap on impact gun and ratchets etc off my 25ltr tank portable comp and 40m+ ! hose and can use it all day long taking engines gearboxes etc out, I can take four wheels off without a problem it is all down to the differential pressure, and quality of gun most pumps are set to wait till the tank gets down to 90 ish psi before the pump cuts in mine cuts in at 135 and out at 150.

 

[the snooper]

cheapo guns will use a ton of air as they are designed to be produced cheaply not run efficiently

 

[normspanners]

and quality of gun

 

[J.F]

quality of gun most pumps are set to wait till the tank gets down to 90 ish psi before the pump cuts in mine cuts in at 135 and out at 150.

Yes I would agree, as said mine only gets to 8 bar (116psi) so it's max is still lower than the minimum on your system which makes all the difference. I do use snap on hand tools and there quality is very good but am only using a cheap gun https://www.machinemart.co.uk/shop/product/details/clarke-cat131-professional-heavy-duty-12-air
it does what I need but like you say probably not that efficient.

 

[SmartWerks]

I never really use my windy gun, easier to get a cheat bar out and I work off the floor. But if I used one on a regular basis I would go battery pack route. My couple of mech mates have all gone that route and systems they are a god send. I think me mate uses a ryobi one.

 

[normspanners]

I have several cordless guns but still prefer the power of my air tools they are also a lot shorter than the battery ones
I use the battery guns on rallies for wheel nuts etc but if you need to run off a long driveshaft nut or stubborn suspension bits air takes a lot of beating but the main problem now is crank bolts they can be a royal pain with locktite all the way
my latest snap on gun was £300+ and would not be without it and its spec is • Unit delivers an outstanding 1,190 ft. lb. (1,613 N•m) of Bolt Break Away Torque!
• 810 ft. lb. (1,094 N•m) of Recommended Working Torque no way a battery gun can compete.

 

[jordan1]

I have one of their guns, I think that if you want anything more than short bursts your compressor will struggle IMO.

 

[Rig Pig]

I must dig my gun out and have a look at it, I was given it about 15 years ago because it had stopped working - so I popped it on the shelf to sort out as a useful tool for home......

 

[brightspark]

ive got a half inch kobe air impact driver its not bad and ive got a cp 3/4 drive as well its a killer u realy dont need a big compressor to run it just a one with decent size tank and a half inch outlet and pipe to gun so u dont loose cfm and psi . i mean how many nuts are u taking off at once 4 or 5 . its nothing a few pulls of the trigger isnt going to empty the tank

 

[blenkie1]

I have several cordless guns but still prefer the power of my air tools they are also a lot shorter than the battery ones
I use the battery guns on rallies for wheel nuts etc but if you need to run off a long driveshaft nut or stubborn suspension bits air takes a lot of beating but the main problem now is crank bolts they can be a royal pain with locktite all the way
my latest snap on gun was £300+ and would not be without it and its spec is • Unit delivers an outstanding 1,190 ft. lb. (1,613 N•m) of Bolt Break Away Torque!
• 810 ft. lb. (1,094 N•m) of Recommended Working Torque no way a battery gun can compete.

The new ones norm are something else and are not that far off them specs. No oiling, no air hoses, no compressor. Middle of a wood working on a forwarder this is what you use. In the workshop do you want trailing hoses pluging in and out for jobs. I can see as technology improves air guns will be more and more redundant. Nearly everyone in our workshop and on the vans carry them.

780 ft/lb of forward/reverse torque and 1100 ft/lb of nut busting torque from Ingersoll rand
135/950nm fastening torque and 1491nm of nut busting torque from a milwaukee

Not that far away?

 

[N2ae86]

Just thought I would update this - gave up on trying to get an impact wrench to run off my compressor and ended up buying a cordless impact wrench instead. Just made so much more sense as its infinitely portable.

Ended up with the new Dewalt impact wrench they have released.

http://www.dewalt.co.uk/powertools/productdetails/catno/DCF899N/

Bought the naked unit and then snagged a new 5AH battery off Amazon for £50. So £200 all in. Got some nice specs and a lot of power!

 

[thinfourth]

I have exactly the same model of impact gun as the OP is thinking of buying and it is excellent

The compressor i use looks like something you would get on special offer in Aldi

It is utter cack

But it was free as it was getting skipped and i repaired it with a christmas card as it had blown a gasket

It is nick named wheezy

It takes 10 minutes to fill the tank, well tanks to be accurate. As wheezy is connected to a big calor gas bottle.

Once wheezy has got it up to pressure then there is very little the impact gun can't shift.


Your air tank is you storage

Your compressor fills the tank

Your tools consume from the tank

What limits how much air you tools can take is the size of the pipe from tank to the tool

how long you can run the tool is how big you tank is

How long you tank takes to fill is dependent on how big the compressor is.



An impact gun is never run non-stop so you can get away with a far smaller compressor then you would think.