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Impact wrench: Torque vs Loosening Torque

J

JorWood

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Jan 16, 2016
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I know this has probably been asked but I can't seem to find that answer.

I'm looking at Aircat's website considering the 1150 or 1250k for the bigger jobs. I don't understand which torque rating I should be going off of for comparison sake. The 1250k is rated at 950 ft-lb of Max torque and 1300 ft-lb of Loosening torque. What's the difference and which is the most relevant?
 
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CobraRed

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May 30, 2014
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Working and Max torque are both standards that have an accepted practice for measuring and replicating.

Peak
Nut Busting
Loosening
Breakaway

And the other half dozen made up names are all intentionally misleading and can trace their roots back to a marketing meeting in leather chairs more than any shop environment.

Even the few extras that inherently do have a definition, there's no universally accepted method or tool of measurement to replicate, thus they are brand specific so you can only compare within a brand specs under "Super Dooper Pooper Torque".
 
P

Pontiac787

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May 31, 2016
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As I understand it, loosening torque is the amount the fastener is tightened to before the impact is used to remove it.

Tighten a nut with a different tool to 1,200 ft-lbs. then use the impact gun to try and remove it. If it can do it, but can't remove a nut tightened to 1,205 ft-lbs. they will market the gun as having 1,200 ft-lbs of "nut busting" torque.

As already mentioned there are a lot of variables and no consistency between manufactures so it isn't really a meaningful stat.
 
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Yellow1098

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Jul 7, 2013
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How do you use the impact to put on and retighten the lug nuts .....what torque rating should you have for that?
 
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J

JorWood

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Thanks that does explain it. I appreciate companies like Aircat giving both ratings, even if they don't clarify them.
 
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jerseykat1

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I typically ignore the fictional rating and base my decision on max reverse torque.

That said. I'm sure the BS rating gets a lot more product sold.

Sent from my Nexus 6P using Tapatalk
 
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Marlin

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Be careful, Aircat rates some tools at 120 psi vs most other manufacturers that use 90 psi. Also, the loosening torque number varies by manufacturer because the amount of time the gun is allowed to impact varies, one company might use 30 sec while another uses 5 sec.
 
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Marlin

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SuperXero said:
This best explains it.

http://www.realtoolreviews.com/the-...rque-what-is-it-impact-wrench-torque-ratings/
Click to expand...

He does a good job at tool reviews but he is a little off on this explanation. The temp of the bolt / nut has litle or nothing to do with the ability of the tool to loosen the fastener. A very simple analogy is that threads are like a ramp when you are trying to tighten a nut you are pushing up the ramp and when you are loosening you are pushing down the ramp.
 
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