You were the one who told me to brush up on them and I suggested the same for you. The claims of the 4 foot extension is true {although exaggerated for the point}. Also when i said "wrench" I meant impact wrench. They make a special extension just for that...it has a very thick and sturdy shaft to prevent twisting.

I brought the math, what else do you want?

Wrong, a torque wrench only reads correctly if held by the handle.

"I brought you the math what else do you want"

You brought me a hypothetical example of a tool that does not exist for obvious reasons. That example has nothing to do with a real flex head wrench that does exist and is commonly used. The gauge mechanism is contained entirely in the drive head of the flex wrench and is therefore unaffected by any handle flex while a beam type wrench uses the entire wrench except for the grip thus flexing at the head would modify the gauge system itself. As I said you are comparing apples and oranges. That example proves nothing.

A 4 ft extension would affect an impact wrench profoundly and I have been saying so all along. Why did you wait until now to decide that you were talking about an impact wrench, you never said that before.


"Wrong, a torque wrench only reads correctly if held by the handle"

If the gauge mechanism is entirely contained in the head, unlike a beam type, the handle does not matter.(ok on a clicker type you would have to be anywhere before the click mechanism but the principle is the same).

You said "I have been doing a tiny bit of reading on torque wrenches and have FOUND they are generally between 3%-6% accurate" and then you went on to explain it to me. This tells me a lot about what you know about the subject. You are just discovering this? The tolerance ratings on torque wrenches are common knowledge and are usually listed with a wrench's specs, heck even Harbor Freight often tells us the tolerances in their catalog!
You continue to insist that a common tool sold by many big name tool outfits and used all over the world is inaccurate and cannot be reliably used for what it is designed for, this too says a lot about what you know. I also asked you about a couple of points and you chose to ignore them. So if you are trying to prove something I think by now you have and it is apparent that this is going nowhere so at this point I think I will just agree that by golly that dang sheep is white after all.

you type a lot and say little.
when I said wrench {my first post} I referred to the previous post in which the guy was trying to pull a trans from a ford. He was using an impact. I used to work in a tranny shop and I bet I know which bolt it was even!

The clicker type wreches must also be held by the handle despite your claims that they don't.

It doesn't matter where you put your hands on the torque wrench to pull it. If you put your hand in the middle or the end it makes no difference. If you could turn the head by hand that would work, but you can't so they add a handle to get leverage. The handle is just a piece of metal tube. Do you think it has sensors in the handle to tell where your hands are????

NXS, One thing is for sure what you typed says a LOT just not what I think you intended

I'm not sure what your gettin at oldred, I was referring to his statement about the handle.

OK, I just shot an email to customer support at Snap-On tools. Let's see if they respond.

Rat, My reply was intended for NXS, Sorry for the misunderstanding. I think you and I are in agreement here.

Where you hold the wrench makes a difference:
http://www.sacskyranch.com/torquew.htm

NXS read that carefully, that deals with mechanical precision errors in calibration using calibration equipment and again has nothing to do with handle length and leverage factor. Go back and read the first link that farna provided it gives a good example of WHERE handle length does matter. Man if you were not so obsessed with proving a point and would take an honest look at this I think you would see it clearly. I don't think you can honestly believe that a flex head wrench cannot work because they are there for the whole world to see and use so instead of trying to find something to prove they don't work why don't you try to find something that explains it better than I was able to.

I have read the link Farna left, how about you read the link I left? I have shown you the math for the flex head and have shown you that it matters where your hand is and that it WILL affect the readings, FACT. Moment of inertia will affect the readings, friction from the lateral force on the bolt {which occurs when an extension is used} will affect the reading. How about you find something that proves what you are saying ...or we wait on Snap-on CS to respond. Your call.

You haven't answered my question yet. How does the torque wrench handle know where your hand is? It's a hollow piece of steel. Here's my torque wrench. How does it know where I hold it?

Rat, He will not answer my questions either because he has no answers. This started with trying to clear up a common myth about extensions and torque wrenches then flex head torque wrenches(don't really understand what he's trying to prove here) and now it has taken a turn into left Field and we are now dealing with mechanically induced errors when calibrating a torque wrench. Up until now it was simple laws of physics dealing with levers and applied force but this is an entirely different subject. If you read that complete link it is quite clear what it is about but he thinks he has found something and he is now trying to explain the physics that we have been giving him from the beginning.

NXS, You gave me the math? MATH You are referring to the hypothetical beam type wrench?

Ok lets look at that hypothetical wrench and lets use your "math"

You said-"If you don't think of a click style but rather an older(?) beam style with the pointer and then imagine it being tilted at a 45 deg angle, you would now have to pull twice as hard to reach the SAME torque on the bolt head"

But this IS EXACTLY what we are trying to tell you, You would have to PULL HARDER with a shorter handle to reach the SAME torque reading! The flaw to your example, which truly would be in error, is that with the beam type wrench you would be changing the gauge mechanism itself while with a flex head the gauge mechanism would be unaffected since it would not be changed by handle position. You cannot seem to separate the resistance(torque reading) from the applied force. I will try once more Lets assume we want a reading of 75 ft/lbs and we are going to use the wrench that RAT showed us. If we pull, with the grip, until we reach this setting then we will exert a certain amount of force over a given distance, determined by handle length, to arrive at this setting. This will be the total amount of energy expended since you do seem to grasp the energy term. Now if you grip the handle about half way down you will have to apply more FORCE over a shorter distance(due to the now shorter lever=less force multiplication) to arrive at the SAME reading! The shorter lever with more force applied=the same energy expended as the longer lever with less force applied. So the shorter the handle the harder( more force) you would have to pull to arrive at the SAME torque(resistance) The torque gauge measures the RESISTANCE AT THE FASTENER it does NOT measure how much FORCE is applied to the HANDLE! At a reading of 75 ft/lbs, or any other reading, the amount of force needed at any point on the handle will be determined by the distance from that point to the center of the fastener but this will not take into account any mechanical errors which may or may not occur depending on wrench design. It is quite obvious that a beam type wrench would be affected severely by applying force anywhere other than the grip but this would be mechanically induced error and again has nothing to do with the principles involved here. The fact that flex head wrenches do work is not in question here since they are used all the time so why don't you spend all this time and energy you are using trying to prove they don't to understand how they do.

What an absurd question! Has Snap-on answered your questions either?
For clarification:
a socket extension will affect the amount of torque applied to a fastener....although it is not anything to be concerned about. This is due to lateral forces and the moment of inertia of the extension. A slow steady pull will fix the moment of inertia problem.

The real debate and serious question is about a flex head wrench {and now if it matters where you hold the handle? yes, it DOES matter}. How about it oldred ...bring some proof to your assertion that a flex head does not change the reading verse actual Tq and also that it doesn't matter where you hold the wrench. I don't mean a thesis of your ramblings but rather PROOF. I won't hold my breath.

NXS, Ramblings? Those "ramblings" are wrong? If so please show me where and I will stand corrected. What exactly do want for proof? I tried to give a sensible explanation based on elementary physical science. Is there a simpler approach? If so what? I made it as plain as I could and I don't see how it could have been much simpler. If you can not understand then there is nothing else I can say. I tried to get you look at the explanation offered by the link from Farna's post that PLAINLY states that length added to the handle end does not affect the reading, maybe you think they are wrong? I tried repeatedly to impress upon you that these flex head wrenches exist and are used all over the world, don't that mean anything? What kind of proof are you looking for?

There is nothing absurd about what Rat asked you. You keep saying we are wrong and he simply asked you to show him why, what is absurd about that? You are now explaining moment of inertia affecting the extension to me? Did I not explain that to you already(affecting impact wrenches using impulse force) This applies to a torque wrench when it is improperly used by "tugging" or "jerking" thereby inducing a much higher rate of force input which in turn increases the inertial forces to a significant amount. DANG IT I am rambling again!

BTW, How old are you?