Torque wrenches, adapter, socket extensions-Read 1st post BEFORE Voting please!!

I have an interesting debate going on in another forum that I wanted to see what the general belief is here. The debate has to do with torque wrenches and adapters or socket extensions.

I state that when you use a socket extension with a hand torque wrench (Not an air tool) that the torque is not affected regardless of extension length because even though the extensions does twist, it will still apply the direct-line force to the bolt/nut. This has been proven in other engineering and physics forums, as well as in my physics class when I was getting my automotive degree.

The other guy emphatically says that it will throw the torque off substantially and that I don't know what I am talking about.

Now I remember back years ago that the story was that it did affect the torque, but our automotive course program showed us that it was an old-wives tale. What is everyone's take on this? And please, if you post a comment, include supporting information. Don't just say "yes it does", or "no it doesn't"

 

I have always been told that it does, due to the twist from the extension. This is through my father who is an gas turbine and heavy diesel mechanic
Edit: if it is one solid extension it shouldn't be affected but compiling multiple will cause a torque loss

 

http://www.answerbag.com/q_view/2279251

 

From what i understand the only time an extention would throw off the torque is if it were adding to the overall length of the wrench... an adapter coming out at a 90 degree wouldn't.

 

I had always thought the same as I grew up until I took the physics class. And on your edit, multiple extensions still do not affect it any since it is a straight-line pull. Now if you were using an impact gun, then yes!

Yeah, lots of those out there. None of them truly "legit" answers that I can use. You can find just as many of those "question/answer" websites that say it does, as those that say it does not. I have actually sent in an inquiry to Snap-on tools, just to get their answer.

Exactly what I have learned as well.

 

more good info...
http://www.norbar-usa.com/calculators/torque-wrench-extension-calculator.aspx

 

In going to bring this up to my statics teacher, from what you say it makes sense. But what about the error accounted for sloppy cheap tools that are not made to great tolerance or precision?

 

As an aircraft mechanic we are taught that extensions on the drive don't mess with torque values. Only when you add on to the handle is when you should be careful.

 

I'm gonna say yes it does. The extension (at high loads) will twist and absorb some of the energy /force, but it is so little that it is negligible for most automotive use. This is if you are using at least a decent/good set of tools and the right "size" of tools.

Currently in school for my ME degree. I've takin my strengths and material class.

 

from the Snap-On web site...
http://www.snaponindustrialbrands.com/dsn/wwwsnaponindustrialbrandscom/Content/PDF/CDI%20TechAngle%20Manual.pdf

http://alltorqhydraulictorque.com/pdfs/equipment/Snap-On-Manual.pdf

 

I would agree with you on this on the point of if an impact or air tool was being used. However I do not agree when using a hand-pulled torque wrench. Since you are in school, would you mind asking a physics instructor to answer the question, and perhaps point to a physics law that supports that? I ask because when we took physics that specific subject was discussed and proven to not affect torque.

 

Awesome find! Thanks. That supports what I was saying.

 

An extension would not affect the applied torque. Simple physics.

 

you are correct, bill. we're not talking about presurized fluids flowing through a pipe, or eletrical voltage drops over distance. every time you see a drop of a unit energy or flow, it is due to friction. with a hand torque wrench, we are dealing with a statics problem. there is no loss or resistance of any sort due to friction or forces within the system. the only force resisting the turning of the wrench is the nut/bolt against the bearing surface. therefore if you apply X units of force into the system, that same force will be applied to the end piece of hardware.

to put it in terms that may be a little more relatable to those who don't have a background in physics/engineering/etc, imagine tossing 200lbs into the bed of your truck and letting it sit there. even though the leaf springs (socket extention) flex, there is still an extra 200lbs on your tires (nut or bolt).

as long as what you are bending or twisting stops doing so before it breaks, it will transfer 100% of the load applied.

if you are still doubting this, tighten down a nut onto a bolt. put a torque wrench on on, and a torque wrench with an extension on the other. while holding one stationary, turn the other. assuming both are calibrated and set to the same amount, they will click at the same time.

 

I'm saying yes, just because it's not a solid locked piece. They wiggle and they can throw off your arc. If they were of tighter tolerance, then I'd say no.

 

You would think that was obvious, but this guy on the other forum is just totally convinced I am wrong and he is right.

 

The only "extension" that would affect torque would be a cheat bar extension.

 

I work on military planes and have to use torque wrenches all the time. with the one post saying its not a solid piece and I know there is a formula to figure the difference and how much high the torque setting may need to be. if you would like to know the formula I can get it to you but I have to wait for a work laptop to be available.

 

It seems as if everyone wants to argue with you about basic stuff, I was proven wrong and that's that.

 

Everyone has there opinion on the right and wrong. if you learned it doesn't then it doesn't some people learn different. imo