Impacting REALLY tight nuts!!

[Aviatordave]

Hey folks,

I have recently bought an Ingersoll Rand 2135QXPA 1/2” impact driver. It’s maiden voyage took place the other day when I had to change out the shank on a weight distribution hitch for my travel trailer. There are two 3/4” bolts holding the shank to the hitch head. The manual says that they’re to be torqued down to 260 ft-lbs. The closest place I could work on it, relative to my compressor (80 gallon, 5hp 19CFM at 90psi) required me to run a 100’ 3/8” rubber air hose. I have the working pressure on the compressor set to 90 psi. I bought the hitch with the trailer, used, from the original owner. I don’t know what those nuts were torqued down to but they were on there good! They are locknuts. The kind with a nylon o-ring. I oiled the impact wrench up with tool oil so it’s lubricated well.

Them’s the facts.

Anyway, this setup required a 1-1/16” deep socket. The tool claims to be rated at 1100 fl-lbs of break away torque. I thought it wouldn’t be a problem, but MAN! It *BARELY* broke those nuts free. It sat there just hammering away with what I thought, at first, was no movement. After watching carefully, it was turning the nut . . . Just very slowly. You could just see the socket size marking moving a little with each hammer blow.

After the getting the nuts broken loose and having to put a wrench on the other side on the bolt head to stop it from spinning, the impact driver still took it’s sweet time backing those nuts down the threads. Only when the nylon o-ring cleared the last thread did it spin up fast to take the nut off the last few threads of the bolt. Now . . . I was holding a 1/2” ratchet wrench with a 1-1/4” socket on the bolt head and I could feel every hit of the impact wrench through the socket wrench in my other hand. It occurs to me that my arm not being stationary enough on the bolt head side could be robbing the impact wrench of it’s power.

Does this sound normal for an impact wrench to behave like this? I’m kinda new to impact wrenches so I don’t know what variables affect them. Would the 100’ of rubber hose cause any loss of power? Do nylon lock nuts that big just make it slow going for an impact driver? I can see them making things spongy. Maybe it’a a combination of all three factors? Long hose, nylon o-rings, non solid hold on the bolt head with my hand on the ratchet wrench?

I’m still inside a window of ability to return the impact driver if it sounds like it should be stronger.

What do you folks think?

-Dave

Here’a a pic of the setup:





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[Firstram]

That long hose will really rob airflow, try it again close to the compressor and see if it's better. A pony tank with a short hose would get your back up if you need to work out in the yard

 

[Lwel9226]

That long hose will really rob airflow, try it again close to the compressor and see if it's better. A pony tank with a short hose would get your back up if you need to work out in the yard

Plus... use a combination wrench instead of the ratchet for backup.... impacts don't like crescent wrenches for backup either....

LynnW

 

[demarpaint]

You need 90 psi at the tool, 90 psi in the tank and 100' of hose had the tool working with a lot less than 90 psi. It would be very weak with that much hose and 90 psi at the tank.

 

[Wrench97]

Air pressure drops in a hose the longer the hose the less pressure at the working end.
Plus 90 psi at the tank is low, if you have a 1/4" pressure regulator on the compressor that's a CFM killer.
Most shops the compressors are set to 150-142 psi.

 

[ndnchf]

I have a battery 1/2" impact rated at the same breakaway torque. Nothing seems to stop it, it truly us a monster.

 

[joey1320]

We run 140psi at the shop for our air supply. At 90psi, we would have a lot of problems like you had. The long hose is also robbing you.

If you are "stuck" with this combination, consider a cordless half inch impact gun. I use a Milwaukee and has been a blessing not dealing with air hoses.

 

[johninct]

Throw your regulator away and then report back.

 

[Kscardsfan]

Low air pressure at the tool I’d bet. I have mine set over 125-130 psi to get 90 at the end of the hose. I bought a M18 cordless impact a few years ago and I haven’t used my air impact gun since. It hasn’t quit on me yet and I’ve thrown some nasty stuff at it.

 

[jonesg]

All very true about the long hose, also consider what the restart pressure is, some go down to 60 psi before cycling up again.
I only have a HF 21 gal but I have it set to 125 psi and I start using it before the compressor shuts down, around 115 psi, that way it doesn't drop down low.

I run rapidaire hard plastic hose and have the garage plumbed with 3 outlets, I think the hard piping helps.
Compressor is in the house, garage is 15 feet away from house, line runs underground.

Also have the milwaukee lineup, they're worth it.

 

[seber]

In addition to the long hose, you have the wrong back up. Use a box end and let it brace against the hitch mount instead of your hand.

 

[subroc]

Elastic stop nuts will provide resistance right till the plastic/nylon material clears the threads especially if they were new at installation and there is some corrosion they have to overcome.

 

[SeisMec]

Everything above is right! Nitty gritty of my post is in the final paragraph.

If you don't already how the impact mechanism of an impact wrench/gun/driver works, take a look at this 4 minute long video. (If you're of the TLDNR/ADHD/Reader's Digest persuasion, the last 2 minutes is probably enough.)

There is no standard procedure for determining "break away torque". (The TLDNR crowd can skip the next 3 paragraphs)

Every manufacturer devises their own test procedure. Despite that, I wouldn't describe the number as completely meaningless. Imagine that you used a torque wrench to tighten a fastener to *** ft lbs. If done correctly, the last part of the turning action was done: to a smooth stop; at the completion of the final 3/4 to 1/4 turn of the wrench. Having tightened the fitting to *** ft lbs, further imagine that you replace the torque wrench and socket with a striker wrench.

Now imagine that you've improvised a mechanism to deliver a hammer blow to the strike anvil of the wrench at a point exactly 1 foot from the centerline of the fastener/wrench broach. And that the hammer blow's impact delivers exactly *** lbs of force at the impact point on the wrench.

At first blush, you might suppose that nothing would happen. If so, you've failed to account for momentum and a few additional factors like the distortion of the threads, bolt stretch, ... In fact the bolt will turn a little bit further and the "achieved torque" (not a technical term) will be greater than *** ft lbs. Additional hammer blows will push the "achieved torque" value higher - until some maximum value is reached or the fastener fails in some way (threads strip out or the fastener shears away). If the fastern does not fail, then the final "achieved torque" will be the same as the "break away torque" required to unscrew the fastener.

To achieve greater "break away torque" with the only gun you have. Mostly in no particular order, but for each and every difficult fastener -

• Squirt a good shot of air motor oil directly into inlet fitting of the air impact just prior to use. This results in a better seal at the vanes of the air motor and makes the very first few impact blows significantly more powerful.
• Free spin the gun to drain the air tank and cycle the compressor on; wait until the compressor cycles off.
• For thread sizes that are not much larger than the anvil size (eg. 1/2" anvil vs 5/8" thread) try a more massive socket. Deep socket is probably more effective than shallow. Impact vs chrome/hand drive.
• For thread sizes that are very much larger than the anvil size (eg 1/2" anvil vs 1" thread), try a less massive socket. Shallow socket may be better than a deep socket.
• Turn up the compressor maximum output pressure.
• Use a shorter hose with larger id.
• Use an equal length hose with larger id.
• Use a shorter hose with equal id.

Yes, I know that for a lot of people here this is me attempting to "teach my grandmother to **** eggs". But it's intended for everyone else.

 

[Aviatordave]

Wow. That’s a great bunch of advice!! Thank you, everybody.

I should clarify, the tank pressure in my compressor is 150psi. When I said the working pressure was 90, that’s just what I had the regulator output set at because Ingersol Rand said to use 90psi for the tool.
Regardless, what I’m hearing an overwhelming response for, is that the long hose is robbing me of a lot and the ratchet wrench isn’t helping either. Also interesting to think about the nylon having to fight the corrosion on the exposed threads.

Interesting comments on bolt size vs. anvil size. I can’t get away with a shorter socket because of the bolt threads beyond the nut. The sockets are all impact sockets. Much more mass than the chrome sockets I have. When I bought the impact wrench, I bought a set of 1/2” impact sockets to go with it.

I have small 6 gallon pancake compressor. I can get 150 psi in the tank with that but the CFM is abysmally low. I’ll see if that works with a short hose for some brief bursts of breaking power.

If I have to use the 100ft hose (or even a 50ft hose, it sounds like turning up the regulator at the compressor to something higher (125? 130?) is going to help me maintain 90psi at the tool. Is this sound logic?

I have the stuff for plumbing the shop with air. Just haven’t got it installed yet. (1” pipe)

I really appreciate all the tips and advice folks! Sounds like the gun is fine. Just need a better setup. Thank you!

-Dave


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[Wrench97]

Most of those regulators on the pancake compressors are very restrictive I.E. the internal passages are so small that if you have 120 psi at the gun it can not maintain that once the trigger is pulled. They work great for nail guns and staple guns that use very little air to fire.
I ran into this years ago with a old siphon spray gun where if set to 60psi I could not maintain 40 psi at the gun, so imagine what a air hungry impact gun would do.

 

[rlitman]

...I should clarify, the tank pressure in my compressor is 150psi. When I said the working pressure was 90, that’s just what I had the regulator output set at because Ingersol Rand said to use 90psi for the tool...

Not 90 PSI static pressure. That's your problem. I usually set my regulator at 90 PSI too BTW, because my tools run quieter, and nailers don't work so well set higher than that.

The issue here is flow. 90 PSI at the regulator will be 90 PSI at the tool, when the tool is off. But as soon as you pull the trigger, air starts to flow, and the pressure reaching the tool will drop. The longer and smaller the hose, the more the pressure loss.

For S&G, I ran the numbers through this calculator.
https://www.gates.com/us/en/knowledge-center/calculators/air-flow-calculator.html

Your gun at WOT draws 24CFM, which means the pressure delivered to it with 90 PSI on your regulator was merely 59 PSI at the end of that 3/8" 100' hose. Yeah, no wonder it choked.

On that note, crank it to 114 PSI, and I'm betting you'll have just about 90 PSI at the tool when it's actually running.

 

[Aviatordave]

What a great resource! That’s a fantastic calculator to have!! Thank you! (Wonder if there’s an app for that for my phone . . .)

Indeed, no wonder the tool wasn’t working right!


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[Big Bad Jon]

We run 140psi at the shop for our air supply. At 90psi, we would have a lot of problems like you had. The long hose is also robbing you.

If you are "stuck" with this combination, consider a cordless half inch impact gun. I use a Milwaukee and has been a blessing not dealing with air hoses.

If it were me, I’d return the pneumatic impact and buy a battery powered one. If you have a 100’ run, you’re going to constantly have issues. Modern electric tools have made pneumatic tools obsolete.

 

[charbar]

Throw the regulator in the trash.

 

[Skin]

You need 90 psi at the tool, 90 psi in the tank and 100' of hose had the tool working with a lot less than 90 psi. It would be very weak with that much hose and 90 psi at the tank.

90PSI at the tool is working pressure. Trigger pulled it should not drop below 90 so your static pressure is going to be quite a bit higher. For most home compressors and tools that make things go bang you can either remove the regulator or just open it fully and never touch it again.

Modern electric tools have made pneumatic tools obsolete.

Pneumatics are better in
-build quality
-longevity
-noise
-size
-weight
-power output for their given size/weight.
-cost
-run time

Cordless is only better in convenience.

 

[charbar]

Pneumatics are better in
-build quality
-longevity
-noise
-size
-weight
-power output for their given size/weight.
-cost
-run time

Cordless is only better in convenience.

I agree 100% (other than the noise part of it) but OH MY is a cordless so worth it! My Dewalt 1/2" gets beat HARD every day, I can't even remember the last time Ive had an air gun out doing any automotive work.

 

[Skin]

I agree 100% (other than the noise part of it)

Stick your head next to the hammer housing of a cordless impact and then a pneumatic. The cordless will set your ears ringing due to the much higher RPM of the impact blows which is usually 1:1 with the motor RPMs. Add to this there is generally far less mass making contact as well which creates that sharp "clack" instead of a thud of a standard single or double hammer impact. Free spinning of course cordless is quieter but thats not when the tool is working.

Other tools are a different story like ratchets which are much more pleasing to use than most pneumatics.

Cordless impacts in close quarters on a stubborn fastener is guaranteed to trigger my tinnitus.

 

[Jlarson]

Regulators just get in the way of things, you aren't running an air brush or a trim stapler.

 

[Lwel9226]

Pneumatics are better in
-build quality
-longevity
-noise
-size
-weight
-power output for their given size/weight.
-cost
-run time

Cordless is only better in convenience.

TOTALY AGREE! ! ! !

LynnW

 

[seber]

I should have mentioned a trick I used to use when I had the same problem. I put a portable tank next to the tool with a tee on the port. That gave me a high pressure reservoir so the hose size and length was irrelevant.

 

[justanengineer]

Unless your goal is to snap fasteners, a slow and easy removal is what you should shoot for every time. Even if you get more power out of the rattle gun, start it on a low setting and work your way up with plenty of lube.


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[Aviatordave]

I should have mentioned a trick I used to use when I had the same problem. I put a portable tank next to the tool with a tee on the port. That gave me a high pressure reservoir so the hose size and length was irrelevant.

Now THAT sounds like a good idea!!!
I think I even have a T already made up from some other cockamamie idea I had a few years back.


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[pennsylvaniaboy]

milwaukee 2767....no air pressure issues, or compressor that cant keep up, etc.

 

[vanapplebomb]

With a modest 1/2” air impact, 25’ of 3/8 hose, and high flow couplers, I need to set my regulator at the wall to 120PSI to see 90 working pressure at the tool. My 3/4 impacts need a bit more. Usually takes 130PSI at the wall to get 90 at the tool.

One thing I have found to be true is that the weight of the swinging hammer matters on stuck fasteners. Torque ratings are rather misleading, because they don’t tell you anything about how they hit. A heavy slower turning 3/4 hammer hits very differently than a lighter faster 1/2 hammer mechanism. Be aware however, many newer electric 3/4 impacts have the same basic mechanism as the 1/2 high torque impact... which to me is pointless. Every air 3/4 impact I have seen has considerably heavier hammer mechanisms and slower rpm than their 1/2 counterparts. The difference is surprising on very stuck large fasteners. My 3/4 rated at 800 FtLbs will rip a nut off that a 1250FtLbs 1/2 wont touch. On a fresh clean bolt I’m sure the 1/2 will achieve higher bolt tension, but when seized up, sometimes there is no replacement for a big heavy hammer.