Anybody Ever "test" The Torque Of Impact Wrenches?

[Sharky]

Seeems that some of my impact wrenches are loosing power. I stripped, cleaned and relubed them, now they're better. The only "test" i've come up with is to run on a trailer hitch ball / nut and use a torque wrench to measure the force to loosen or tighten further.<br />
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Anyone try something different? Any other ideas or tests that you guys have tried and were the results anywhere near the claims of the manufacturer specs?<br />
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Sent from my SM-T217S using Tapatalk

Sent from my SM-T217S using Tapatalk

 

[Ed ke6bnl]

this guy has tested many impact Real Tool Review on youtube. he has a special device that gives a read out of the max torque.

 

[RJSakowski]

I think your test is most likely OK. I would not use a lock washer and grease the threads and flat of the nut to minimize stiction.

 

[Holescreek]

I rebuild the ones we use in the lab here at work, rebuild kits are a lot cheaper than replacement. Ours have nylon/plastic vanes inside that get worn.

 

[Sharky]

I rebuild the ones we use in the lab here at work, rebuild kits are a lot cheaper than replacement. Ours have nylon/plastic vanes inside that get worn.

My IR 231A's & IR 2131 have a glass filled/fiber type vane, the cheapo HF's have a plastic only.
I've replaced some of the plastic vanes in the cheapo's with IR vcanes and they seem to hold up a lot better.
It seems as there are only a few vane styles and sizes so many are interchangeable.

#1 cause of failure is no grease in the bearings/hammer/anvil.

 

[joshua43214]

I will come out with my "there is a right way and every other way" speech now.
I suppose I should also mention that in a previous life I was a fully certified ASE master tech, and a tier III BMW tech. Most of the shops I worked in required we do final wheel torqueing with torque wrenches because even good impacts are inconsistent, and toque sticks are even worse.
So...
The worst possible way to check torque is to put a torque wrench on a tight bolt.
The only thing worse is to loosen a bolt with a click style torque wrench, DO NOT DO THIS! Ever!
I watched one Mr Fenner (I have huge respect for this man) on YouTube when he was trying to find how much torque to use when he was rebuilding a bearing block of some kind. This is a guaranteed way to simultaneously over torque the nut on re-assembly, and ruin the calibration of the wrench. I was not the only one to come down on him for that video in the comments, it is really bad practice. It will actually void a SnapOn warranty. Loosening a bolt can take several times the tightening torque. If you measure the amount of torque required to loosen a bolt, you can end up using several times the correct torque to put it back on.
Ok, enough rant...

The nut/bolt must be in motion when taken to torque. If the fastener is not turning when you reach torque, the reading is false. You should also make sure all the threads are clean, and lubed. Published torque specs take turning friction into account, and they assume the thread is clean and lubed.

The best way to check the torque when you do not have a calibration machine is to bring the fastener to torque, mark the position of the nut/bolt, loosen the fastener, and turn it back to the same position using a beam style torque wrench. You will be able to read the amount of torque off the scale. You could do this by trial and error with a click style wrench as well. Beam wrenches are by their nature far more accurate than click wrenches and they never lose their calibration.

I found that I could gage applied torque from an impact by the feel of the socket in my fingers. I could always hammer a bolt down to with in a few pounds of the specified torque just by feel. I have used many different types of impacts, they all produce inconsistent torque because all the variables that exist between pressure/volume and wear. If you want something to be at a certain torque, use a torque wrench. Impacts are for rapid assembly when torque does not matter or rapid disassembly.

 

[Sharky]

The best way to check the torque when you do not have a calibration machine is to bring the fastener to torque, mark the position of the nut/bolt, loosen the fastener, and turn it back to the same position using a beam style torque wrench. You will be able to read the amount of torque off the scale. You could do this by trial and error with a click style wrench as well. Beam wrenches are by their nature far more accurate than click wrenches and they never lose their calibration.

Makes sense, thanks for the input.

 

[Mark in Indiana]

I never consider it because there are too many variables that effect torque consistently. If I'm using an impact on fasteners where torque is important, I dial the impact back then finish with the torque wrench. I learned a hard but good lesson about that, with my truck brakes several years ago.

 

[davidh]

i have and do use a "Skidmore-Welhiem" torsion testing machine on all the ones i fix. it measures "tension" on the known diameter test bolt. reason is, a lubricated test bolt with know size and lubricated test nut has been the old standard measurements of air tools. example, the handbooks and literature from ingersoll rand and chicago pneumatic industrial side lists tension for a given fastener.
i have been told our good friends at Cat have suggested tightening bolts with a fixed size / length wrench as tight , then a "flat" or part of a "flat" tighter.
when Skidmore was asked about how to determine what the torque value is based on the tension indicated on the test tools pressure gage their reply was to set your own standard by applying a standard amount of air thru a standard size air hose using a new tool average. then run the bolt up tight, and hammer for 5 seconds, and do this with every test. i find with this test, a IR2135TImax will squeeze aprox 35000 psi on the tester, its advertised at 1100 foot lbs of ultimate torque. a IR2145 TIMax will pull nearly 60,000 psi. i don't remember their advertised max torque.
i still repair tools for a few businesses that have been excellent customers so i have lots of parts available . i purchase vanes by the hundreds.
i would be happy to run the test on any impact for the guys here. all it will cost is postage both ways

 

[cvairwerks]

Saying that torque should always be on a lubricated fastener is not correct. It all depends on what engineering calls out for the installation. We do torques with dry or wet threads, torque above run-on requirements, torque to a specific number and then advance the fastener a specific angle and even a few torque to stretch limits. The majority of ours are torque to a specific amount after run-on, with both wet and dry threads based on the specific installation. In a normal shift, I can have torque call outs from 2-5 inch-pounds all the way up to several hundred pound-feet.