Tool ignorance - impact & compressor

[bruceb58]

Re: Tool ignorance - impact & compressor

There is that “volume has nothing to do with how the tool works" in another sizing calculation. :lol:

I don't question your calcs on the pressure drop of long hoses. I even stated that myself. That would be the biggest issue for an impact wrench not working properly due to low pressure.

I can take all the lug nuts off one wheel before the pressure of the tank drops to a point where the compressor even kicks back on. I am sure you will agree that the CFM rating of my compressor is not a factor in this instance correct?

And I think we agree that pressure drop due to an undersized hose will have that same pressure drop whether a compressor has a CFM rating of 1 or 10.

 

[Fun Times]

Re: Tool ignorance - impact & compressor

This slow motion of how an impact wrench works video was kind of cool to see. Skip ahead to the 2 minute mark to see the internal workings.

Slow Motion - How an Impact Wrench Works - YouTube

 

[bruceb58]

Re: Tool ignorance - impact & compressor

If the OP decides to replace instead of repair his current tool, this is the one that I have. For the money, you can't beat it if you are just taking off passenger car and light truck wheels.
Ingersoll-Rand 231C 1/2-Inch Super-Duty Air Impact Wrench - Amazon.com

I have had some of the cheap ones. Never again.

 

[bigdee]

Re: Tool ignorance - impact & compressor

If the OP decides to replace instead of repair his current tool, this is the one that I have. For the money, you can't beat it if you are just taking off passenger car and light truck wheels.
Ingersoll-Rand 231C 1/2-Inch Super-Duty Air Impact Wrench - Amazon.com

I have had some of the cheap ones. Never again.

Bruce,I was surprised to see that IR wrench was made in China. There is a huge Ingersol-Rand factory close to where I live that manufactures similar looking impact wrenches....wonder where those are sold!

 

[Tim Frank]

Re: Tool ignorance - impact & compressor

I don't question your calcs on the pressure drop of long hoses. I even stated that myself. That would be the biggest issue for an impact wrench not working properly due to low pressure.

I can take all the lug nuts off one wheel before the pressure of the tank drops to a point where the compressor even kicks back on. I am sure you will agree that the CFM rating of my compressor is not a factor in this instance correct?

And I think we agree that pressure drop due to an undersized hose will have that same pressure drop whether a compressor has a CFM rating of 1 or 10.

A bit like running an arc welder on bell wire?

 

[MTboatguy]

Re: Tool ignorance - impact & compressor

Bruce,I was surprised to see that IR wrench was made in China. There is a huge Ingersol-Rand factory close to where I live that manufactures similar looking impact wrenches....wonder where those are sold!

They probably sell them in......


China!

LOL

 

[bigdee]

Re: Tool ignorance - impact & compressor

They probably sell them in......


China!

LOL

To use on their assembly lines to manufacture look-alike impact wrenches....LOL

 

[gm280]

Re: Tool ignorance - impact & compressor

FYI, I don't know if any of you know much about IR (Ingersoll Rand) tools. They, supposedly, were the very first pneumatic tool builders in the world. And they built their first tools to use in mining operations. Gold and coal mines used them first. Now a lot of name brand tools are built in China claiming they are built in a ISO9001 company. Again, I don't know if any of you are familiar with what a ISO9001 company is. Well I know first hand all about what is ISO9001 compliance company. We were forced to be ISO900X compliance in our Software office. It is such a bogus standard that it changes near yearly so they can make tons of money recertifying companies and office all the time. It amounts to nothing more then charts and paperwork to show you are watching your production for possible flaws or problems before they get into the market. So easy to make paperwork trails after the fact. So IR has a lot of their designed pneumatic tools manufactured in China like so many other tool and produces these days. Labor and of course our government regulation, fees and taxes forces many companies to do just that. But that is another story for some other comment board.

 

[bruceb58]

Re: Tool ignorance - impact & compressor

Bruce,I was surprised to see that IR wrench was made in China. There is a huge Ingersol-Rand factory close to where I live that manufactures similar looking impact wrenches....wonder where those are sold!

Yep, looked at mine...made in China.

 

[dingbat]

Re: Tool ignorance - impact & compressor

I can take all the lug nuts off one wheel before the pressure of the tank drops to a point where the compressor even kicks back on. I am sure you will agree that the CFM rating of my compressor is not a factor in this instance correct?

The CFM rating of a compressor is the units ability to maintain the supply a given volume of air at a given pressure regardless of tank size.

You got your lug bolts off only because the minimum available energy (CFM) exceeded demand. In the case where the guy couldn't get his lug nuts off, demand exceeded available energy. The units inability to supply a given volume at a sufficient pressure to produce the Work made the unit's CFM rating an issue.

Remember, your powering a rotating piston motor using a compressible gas and your storage tank has a finite volume and pressure capacity. Each stroke of the air motor diminishes the stored energy in the tank until the stored energy reaches equilibrium with the Work and the tool stalls or the low pressure limit kicks in and the compressor refills the tank. Mind too, that cranking up the pressure is counter productive. As the pressure goes up, the flow drops.

And I think we agree that pressure drop due to an undersized hose will have that same pressure drop whether a compressor has a CFM rating of 1 or 10.

A units CFM rating is it's ability to maintain a constant flow at a given volume and pressure. A unit rated at 10 scfm supplies 10 scfm of air at a given pressure. A 1 scfm system would supply 1 scfm of air at a given pressure.

Pressure drop is the result of friction caused by a volume of air flowing thru the hose. See where this is going?

Assuming, 50' of 1/2" diameter hose.... the 10 scfm rated compressor would generate a pressure drop of 0.68 PSI at the end of the hose. The 1 scfm rated compressor would generate a 0.01 psi drop.

 

[bruceb58]

Re: Tool ignorance - impact & compressor

Assuming, 50' of 1/2" diameter hose.... the 10 scfm rated compressor would generate a pressure drop of 0.68 PSI at the end of the hose. The 1 scfm rated compressor would generate a 0.01 psi drop.

For the OP, his 5 CFM impact wrench will draw 5 CFM through the hose regardless of what the compressor is rated for.

He has a 20 gallon tank. If he runs his 5 CFM tool for 5 seconds, he consumes 0.42 CF which is equal to 3.2 gallons. If he started with 110 PSI, he is down to approx 92 PSI in the tank.

Yes, if he runs his tool for minutes straight, he will have an issue with the CFM of his compressor recharging his tank.

Compressors are rated for the compressor itself to recharge the tank. Has nothing to do with the flow of air the tank provides the tool through the hose. You could have a 0.1 CFM compressor filling up a 10,000 gallon tank and that full 110 PSI tank could provide air for that tool for a very long time before it dropped to a pressure(90 PSI) where the tool wouldn't put out full torque. The compressor is basically the battery charger and the tank is the battery. The battery can supply way more current than the battery charger can charge it at.

Do you agree that he can see if his tool is operating properly within 5 seconds? I think you are more worried about a long term use and I agree with you on that.


My finish nail gun uses 4 CFM and I run it just fine off my pancake compressor that is 2 CFM. Since the duty factor is less than 5%, there isn't an issue.

 

[bigdee]

Re: Tool ignorance - impact & compressor

For the OP, his 5 CFM impact wrench will draw 5 CFM through the hose regardless of what the compressor is rated for.

He has a 20 gallon tank. If he runs his 5 CFM tool for 5 seconds, he consumes 0.42 CF which is equal to 3.2 gallons. If he started with 110 PSI, he is down to approx 92 PSI in the tank.

Yes, if he runs his tool for minutes straight, he will have an issue with the CFM of his compressor recharging his tank.

Compressors are rated for the compressor itself to recharge the tank. Has nothing to do with the flow of air the tank provides the tool through the hose. You could have a 0.1 CFM compressor filling up a 10,000 gallon tank and that full 110 PSI tank could provide air for that tool for a very long time before it dropped to a pressure(90 PSI) where the tool wouldn't put out full torque. The compressor is basically the battery charger and the tank is the battery. The battery can supply way more current than the battery charger can charge it at.

Do you agree that he can see if his tool is operating properly within 5 seconds? I think you are more worried about a long term use and I agree with you on that.


My finish nail gun uses 4 CFM and I run it just fine off my pancake compressor that is 2 CFM. Since the duty factor is less than 5%, there isn't an issue.

x2^^^ I like the analogy with a battery

 

[bruceb58]

Re: Tool ignorance - impact & compressor

And sorry to the OP for totally sidetracking your thread.

 

[gm280]

Re: Tool ignorance - impact & compressor

bruce58, you have proven my original post about it not being his compressor quite well. I have a IR DA pneumatic sander that uses over 14CFMs. But my 4.5HP compressor can't provide that many CFMs. But the DA sander still works great for about 30 seconds to a minute before it drops too low to be useful. So his impact wrench should be capable of loosening lug nuts, if it was in proper working order...

 

[dingbat]

Re: Tool ignorance - impact & compressor

He has a 20 gallon tank. If he runs his 5 CFM tool for 5 seconds, he consumes 0.42 CF which is equal to 3.2 gallons. If he started with 110 PSI, he is down to approx 92 PSI in the tank.

One problem with that thinking, CFM ratings are normalized for usage. That 5 CFM is the average consumption at a industry standard duty cycle for the tool over a minute.

I checked a couple of impact wrench specifications and they generally use a 25% duty cycle. So... in reality, your 5 second blast of the tool consumed 1.66 cubic ft, or 11.9 gallons. If he started out 110 psi, he's now down to 63 psi. A 50% reduction in efficiency of an air tool is considerable.

 

[bruceb58]

Re: Tool ignorance - impact & compressor

deleted...I give up! :facepalm:

How about this. I will run my impact wrench for 5 seconds and show you the video of the pressure of the tank before and after!!!!! The compressor will be turned off.

Now I am very curious. Do you actually own an impact wrench?

 

[oldjeep]

Re: Tool ignorance - impact & compressor

deleted...I give up! :facepalm:

Probably best

Now I am very curious. Do you actually own an impact wrench?

Doesn't sound like he has ever even used one.

 

[bigdee]

Re: Tool ignorance - impact & compressor

So... in reality, your 5 second blast of the tool consumed 1.66 cubic ft, or 11.9 gallons. If he started out 110 psi, he's now down to 63 psi. A 50% reduction in efficiency of an air tool is considerable.

So what? 63psi should spin the nut off just fine after that 5 second blast broke it loose. He will just have to wait until the battery,I mean tank re-charges before moving on to the next nut!

 

[oldjeep]

Re: Tool ignorance - impact & compressor

So what? 63psi should spin the nut off just fine after that 5 second blast broke it loose. He will just have to wait until the battery,I mean tank re-charges before moving on to the next nut!

I think at least one of the many things that he is missing is that even if your tank is pressurized to 110 psi, you had better be regulated to around 90 psi for most impact wrenches unless you really like rebuilding them. And if you are seriously consuming 11.9 gallons in 5 seconds then it is truly amazing that my 60 gallon compressor isn't running constantly

 

[bruceb58]

Re: Tool ignorance - impact & compressor

So what? 63psi should spin the nut off just fine after that 5 second blast broke it loose. He will just have to wait until the battery,I mean tank re-charges before moving on to the next nut!

5 seconds should take off all 5 lug nuts!