air compressor/impact wrench help

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Old 09-08-12, 03:25 PM
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air compressor/impact wrench help

Hi all first post here and i think it is in the wrong section so mods please move.

I have bought a 90 lt 3 hp belt driven 145psi air compressor and a cheap ish set of air tools. My problem is my impact wrench rated to 230lb torque can not even loosen a lug nut. There is a dial at the bottom with 1-4 on, i have tried all but still nothing. 4 i think is the strongest setting but i can just about hold the socket still on my hand.

Any idea all my othere air tools seem ok. Many thanks.
 
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Old 09-08-12, 04:20 PM
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What do you have your regulator set on? If you loosen the lug with a wrench will the impact tighten it back up?

almost forgot welcome to the forums!
 
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Old 09-08-12, 04:26 PM
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hi and thank you.

the gun it rated at 90 psi, am using 30 ft pipe 3/8, and got the reg set at 95-105 psi. when it would not work I turned it up to 130 but still nothing
 
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Old 09-08-12, 04:34 PM
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Change the hose to a 1/2" hose. You need volume, not increased pressure. 3/8" is good for nail guns, but for air hogs, a larger hose may help. How are you setting your regulator? You must "dead end" your hose and regulate the output pressure. Moving the regulator without air moving through it won't give you a good reading.
We're probably going to take a trip to the Air compressor forum, so get ready.
 
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Old 09-08-12, 04:44 PM
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so how do u say i should set my regulator up. have air moving through the hose while changing the reg setting. the place where i bought the tools from recommended the 3/8 he had 1/2 but said i would not need it. the tool uses 5cfm
 
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Old 09-08-12, 05:01 PM
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Yes, use a blow tool or some other method of "dead ending" the hose so air will move through it. While the air is moving, set your regulator to the output pressure needed by the tool. Wait for the pressure to build back up and try it.
 
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Old 09-08-12, 05:04 PM
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i will do. thanks for the help
 
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Old 09-10-12, 07:28 AM
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Wait

Before you invest in a bigger hose and massive regulator, I should inform you that ratings on air tools, especially the chinese made no-name ones, don't mean squat. I've seen guns rated at 200 pounds never reach 75. This may very well be the capacity of the gun no matter how much air you throw at it. Know anyone with a brand name tool, like IR or CP? Hook it up to your set up and see what happens.
 
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Old 09-10-12, 07:33 AM
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I have a heavy duty impact wrench but my compressor is smaller than yours and I have no issues removing lug nuts.

Have a neighbor or a friend with a different wrench so that you could compare performance of the wrenches?
 
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Old 09-10-12, 02:14 PM
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Mark, I wasn't suggesting he invest in a regulator, but to set the one he had properly. I agree, some tools don't spool up to expectations, but he has stated he can hold it still in his hand, so I feel there is an air restriction somewhere, whether it be in the regulator's output or in the line feed.
 
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Old 09-10-12, 02:32 PM
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It is a combination of air flow and air pressure at the tool inlet that is important. I notice that more and more compressors today have only a 1/4 inch regulator and also more and more people are using 1/4 inch inside diameter air hoses and often with quick-connect couplers on each end of the hose. These smaller diameter regulators, hoses and the quick couplers will often seriously restrict the air flow at the tool.

Further, pneumatic tools such as impact wrenches, drills, sanders and grinders are rated for their nominal air flow and not their actual air flow in cubic feet per minute. Nominal air flow is the total air flow, including periods of non-use, calculated to a 60 second period. Since an impact wrench is normally used about ten to 20 seconds out of any minute the rated air flow of 4 cubic feet per minute is in reality about 12 to 24 cubic feet per minute while in actual use. The hose, connections, regulator and any filters or lubricators must be sized for this maximum air flow or the tool will under-perform. Some tools, larger sanders and grinders as an example will also have a governor built in that limits the air flow to limit speed. When a load is applied to these tools the speed decreases and the governor opens up to allow more air flow and that also requires larger hoses, etc. I have seen grinders that will barely run on a 1/4 inch hose but cannot be stalled when connected to a 1/2 inch hose.

All that stated, the el-cheapo imported tools are notorious for having inflated ratings.
 
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Old 09-10-12, 03:30 PM
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And a correction in terminology. I used the term "dead ending" the hose, which is a local thing here, and I should have used "open ended hose", which would have been more universally accepted. Just for clarification.
Have you adjusted the regulator, yet?
 
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Old 09-11-12, 05:58 AM
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Larry, he says the other tools work fine with the same setup, so the problem is obviously with the gun. I'm only speaking from experience... I've seen these pin clutch guns that the big stores give away when you buy a compressor. They are so loose, the pins hit the anvil off axis and off center.
 
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Old 09-11-12, 04:43 PM
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Mark, I didn't see where he said anything about other tools, but if they are all working fine, yes, it is in the cheapo wrench. Outlet pressure still needs to be set properly. Most folks don't know how to do it, and think the gauge reading at idle is "it". It ain't.
 
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Old 09-11-12, 06:33 PM
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True, the pressure should be set dynamically, not statically. But you figure the guy bumped the static pressure up to 130#, it has to be around 90# at the inlet. That's why regs don't make much sense on small compressors, you have to be at the cutoff pressure to meet the tool rating at the inlet.
 
 

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