CFM doesn't really matter with a impact gun,Right?

[Nealcrenshaw]

For instance my AC puts out 6.4CFM @90psi.

but the gun uses 9.3CFM @ 90psi.

But since i wont operate the gun that long i shouldn't lose any power,unless i operate it longer than a minute. Correct?

 

[Mike83]

What gun do you have that needs 9.3 CFM??? 1" or spline drive?

 

[Nealcrenshaw]

Its a 3/4" dr. Impact.
200-1300ft/lbs torque range
uses a 1/2" hose, 3/8" inlet
max torque is 1300ft/lbs

 

[Small Engine]

I would think you are right. A larger line size would run the gun more effiecient. That cfm is for the pump to refill the tank. As long as there's air in the tank your fine.

SE

 

[rgates]

I would think you are right. A larger line size would run the gun more effiecient. That cfm is for the pump to refill the tank. As long as there's air in the tank your fine.

SE

This line size remark is correct. The CFM of the compressor is important when you are running a big gun. A "simple" analogy is to attempt to fill a bucket with a 1" hole in it with a 1/2" hose. The hose (compressor) will not keep up with the hole (gun).

 

[rhandwor]

The impacts use air rapidly my 3/4 drive worked much better when I owned a garage with two compressors and bigger air tanks. Air ratchets and small air tools for roloc buffers use large amounts of air. If your compressor kicks on almost immediately and you have to stop frequently you know the problem.

 

[sberry]

A 3/4 gun uses well over 20 cfm, closer to 30.

 

[wantedabiggergarage]

I do hope you have a 1/2" gun as well. In all seriousness, if you bought that for vehicle work (Tim Taylor style) please get good with broken bolts and extracting them.

 

[benjamming]

cfm is flowrate. It should be closer to 30 as my 1/2" IR2135Ti requires 24 cfm to achieve advertised torque ratings (along with other ideal parameters). You will never see the max potential of the gun at only 6.4 cfm supply. However, you many not need to either.

 

[nissan_crawler]

cfm is flowrate. It should be closer to 30 as my 1/2" IR2135Ti requires 24 cfm to achieve advertised torque ratings (along with other ideal parameters). You will never see the max potential of the gun at only 6.4 cfm supply. However, you many not need to either.

Not completely true.

Some got it, some didn't.

The cfm of the compressor has absolutely nothing to do with the cfm the impact requires, until you've drained the air supply and the compressor kicks on.

Technically, you could have an 80 gallon 1 cfm compressor that would run that impact just fine.

In short, it will be fine until your compressor kicks on and drops below the volume needed.

At that point, you might as well set the gun down and wait for it to shut off.

 

[Jeepguy]

You're mostly correct, they use mostly pressure, especially the 1/2" driver and under, although the big ones that you have the trigger pulled for a long time use a ton of CFM. its the whole Torque or Horsepower deal, which one is actually turning the wheels and doing the work? in this case its both. just think about it... CFM is Cubic Feet per minute, are you holding the trigger for a whole minute? usually not.

 

[Uncle Buck]

CFM always matters!

 

[benjamming]

nissan,

Yes, I was considering only non-steady state conditions.

 

[nissan_crawler]

nissan,

Yes, I was considering only non-steady state conditions.

I figured that, just wanted to clarify for the OP.

You can run pretty much anything of a small cfm compressor, it's a matter of how long you're willing to wait for it to charge up again. I'm *assuming* somebody asking this question isn't using it much, and as such, I would just deal with the quick drain/long charge time of the compressor.

 

[Nealcrenshaw]

You can run pretty much anything of a small cfm compressor, it's a matter of how long you're willing to wait for it to charge up again.

This is what i was thinking,but wasnt completely sure.

 

[Conor]

You're mostly correct, they use mostly pressure, especially the 1/2" driver and under, although the big ones that you have the trigger pulled for a long time use a ton of CFM. its the whole Torque or Horsepower deal, which one is actually turning the wheels and doing the work? in this case its both. just think about it... CFM is Cubic Feet per minute, are you holding the trigger for a whole minute? usually not.

I've been thinking about this lately and I'm glad you bring it up....


I have a 5 gallon 2.6CFM @ 90psi Craftsman that I use for filling up tires and Nail guns, works great for me.

I did however want to get a IR 1/2" Impact gun just to make rotating tires easier. I figured that it should work as long as I dont plan on nascar type changes.

Correct?

 

[ImportTuner]

CFM is like size; and size matters. Do you really need a 3/4" impact for home usage? The biggest I have for home is 1/2" ..

 

[Conor]

I figured that, just wanted to clarify for the OP.

You can run pretty much anything of a small cfm compressor, it's a matter of how long you're willing to wait for it to charge up again. I'm *assuming* somebody asking this question isn't using it much, and as such, I would just deal with the quick drain/long charge time of the compressor.

This kinda answers what I've been wondering for a while now.

 

[benjamming]

Of course, you also have to consider line size.

 

[speed bump]

CFM is like size; and size matters. Do you really need a 3/4" impact for home usage? The biggest I have for home is 1/2" ..

Yes I need a 3/4" impact for home use mostly the part where I show off here but I am sure there are lots of other applications. Most important only if I got it really cheap.

 

[SpiderGearsMan]

needs an auxiliary air tank

 

[Nealcrenshaw]

I need the 3/4" impact for those stubborn bolts, like the rear spring shackle,control arms and front and rear axle mounting bolts for my F-150 and E-250.

 

[Danglerb]

I think I would rather use some penetrating oil and stay with the 1/2" impact. 3/4" is going to break stuff accidentally too often.

 

[sberry]

The 9.3 is its industrial avg rating, its actual is about 3 times that.

 

[SpiderGearsMan]

you need a breaker bar

 

[paramudduck]

Man these auto guys act like 3/4 is tank size. I often use a 1" on some of the areas you mention. If the bolt breaks it would have broken no matter what.

 

[Nealcrenshaw]

Man these auto guys act like 3/4 is tank size. I often use a 1" on some of the areas you mention. If the bolt breaks it would have broken no matter what.

I do agree with you.

 

[Jeepguy]

I've been thinking about this lately and I'm glad you bring it up....


I have a 5 gallon 2.6CFM @ 90psi Craftsman that I use for filling up tires and Nail guns, works great for me.

I did however want to get a IR 1/2" Impact gun just to make rotating tires easier. I figured that it should work as long as I dont plan on nascar type changes.

Correct?

Correct, i use a 1/2" impact with my pancake compressor all the time as long as it is short bursts you'll be okay.

 

[fordracing200]

A 1/2" nitrocat or even my uncles 1/2" farmhand tractor supply 550 ft lb special will bust loose leaf spring shackle and U bolts on an f150...my friends dewalt cordless 300ft lb busted the bolts loose on the shackles of a 97 f150 in the junkyard....a 1/2" nitrocat is more then enough for any homeowner.

 

[benjamming]

ford,

You can't have too much help in breaking loose the crankshaft bolt on a Honda for the timing belt job.

 

[paramudduck]

Hey Ford are you in the rust belt?

 

[lurice0]

can i jack my psi up to the max on my ac and expect to get more ft/lbs of torque from the impact wrench?

 

[Strouty]

I need the 3/4" impact for those stubborn bolts, like the rear spring shackle,control arms and front and rear axle mounting bolts for my F-150 and E-250.

You will need more compressor. Stubborn = more trigger time = more air =

 

[sberry]

The other problem besides the small comp is the low pressure, there is no headroom above the demand of the tool and by the time it kicks on even less. A 2 stage is kicking on when single is kicking off, can supply steady to the inlet of a 50 ft hose reel at 135 for 90 at the tool depending on size but this usually involves large 1/2 impact for the most part.
A shorter hose is the number one thing a guy can do to boost the performance of a tool and that is different than"effeciency".

 

[theoldwizard1]

The other problem besides the small comp is the low pressure, there is no headroom above the demand of the tool and by the time it kicks on even less.

True, but depending on the size of the tank, SOMETIMES you can get away with it.

I have seen people take 5 lugs off using a good impact and a small pancake compressor. That fifth one was almost a "no-go" ! You could tell the pressure was dropping and it would have taken a couple of minutes for the compressor to fully recover back to its max pressure.

 

[shampoop]

Most important thing to remember with air impacts is that you don't actually run them at 90psi. You just run them as high as your compressor goes. 90psi is the dynamic pressure at the gun when the gun is in action, the second you pull the trigger the pressure drops. So you run the regulator at 120+

 

[Indexmill]

If you want to run a tool longer with a compressor smaller that the tool's max usage rate, simply add another tank. Usually, this will get you to heaven in the home shop environment. If not, you need more compressor.

A significant exception is sand or bead blasting. Really need a compressor to keep up with the demand of the nozzle ... or it will be a really long blasting job.

 

[unslow1]

If you want to run a tool longer with a compressor smaller that the tool's max usage rate, simply add another tank. Usually, this will get you to heaven in the home shop environment. If not, you need more compressor.

A significant exception is sand or bead blasting. Really need a compressor to keep up with the demand of the nozzle ... or it will be a really long blasting job.

Air sanders are pretty bad also. That does give you built-in breaks but can be annoying.

 

[Loscaldazar]

can i jack my psi up to the max on my ac and expect to get more ft/lbs of torque from the impact wrench?

Yes, but the guns are only rated for 90 PSI of working pressure.

That said, many run their guns at a much higher PSI with no problems. Of course, it's a YMMV, so do what you want. I'd say get a better impact rather than hoping that a few extra PSI will give you the power needed.

 

[Kracin]

cfm is flowrate. It should be closer to 30 as my 1/2" IR2135Ti requires 24 cfm to achieve advertised torque ratings (along with other ideal parameters). You will never see the max potential of the gun at only 6.4 cfm supply. However, you many not need to either.

as long as his outlets are all sized right he would be fine for the first X amount of operation until the tank loses too much pressure.

the whole deal with a compressor having a certain CFM is how much it can keep up with. not the maximum it can put out at any given time.