How do u use a torque wrench?

SeventyMach1 · Apr 15, 2006

nmcgrawj said:
I Dont think he's saying a/a....its a/(a+b).

Exactly.

Wow ... you guys are having a hissy fit over this. This is the EXACT formula that came in the case with my torque wrench ... so I didn't just make the chit up, lol.

JimBowy said:
You need to be much more clear when you give this information. You must not be talking about adding a 6" extension to the socket. This length does NOT matter when measuring torque. Torque is a measure of the perpendicular distance between the force your applying and the pivot point.

Your information is only useful if you are somehow making the torque-wrench "arm" longer. Example: If you put a hollow steel tube on the end of your torque wrench, then you would be obviously applying more torque.

Think about it for a second. When you add in a 6" extension .... and apply "force" to the torque wrench .... it's going to "twist" that extension. It may not be visible to you ... but it's going to twist. So you will have to apply a little more "force" to get the desired torque spec. So no, I wasn't talking about making the torque wrench "arm" longer. That's a whole different ball game.

JimBowy · Apr 15, 2006

SeventyMach1 said:
Exactly.

Wow ... you guys are having a hissy fit over this. This is the EXACT formula that came in the case with my torque wrench ... so I didn't just make the chit up, lol.

Think about it for a second. When you add in a 6" extension .... and apply "force" to the torque wrench .... it's going to "twist" that extension. It may not be visible to you ... but it's going to twist. So you will have to apply a little more "force" to get the desired torque spec. So no, I wasn't talking about making the torque wrench "arm" longer. That's a whole different ball game.

Your going to have to give a better explanation than that.

Like I said, your formula may be correct, but you need to properly define "extension". If you are talking about an "extension" that effectively increases the length of the torque-wrench then this will obviously increase your effective torque and require further calculations. Your formulas apply for the below case:

However, if you are using an "extension" that is perpendicular to the torque wrench - there is no effect on your torque reading. As seen in the picture below:

Roland69 · Apr 15, 2006

yea you can torque bolts backwards with it some threads are reverse threads. Mine has the reverse ratchet switch on it. All it says in the manual about it is to NOT USE AS A BREAKER BAR and to reset it back to the lowest setting when not in use. BTW mine is a Mastercraft Maximum they are really nice well priced tools. I buy all Maximum stuff when they go on sale cause they sometimes go for half price.

SeventyMach1 · Apr 15, 2006

JimBowy said:
However, if you are using an "extension" that is perpendicular to the torque wrench - there is no effect on your torque reading.

This is wrong. Read the article that you got that first pic from. Here's the link. http://www.specialpatrolgroup.co.uk/spooky/torque/torque.html And here's the quote that says that's wrong:

If an adapter is attached to the square drive of a torque wrench, the wrench will not give the actual torque indicated by the setting of the handle. A simple formula however, allows you to figure out what the setting should be to deliver a pre-determined amount of torque at the end of any adapter to the fastener.

JimBowy · Apr 15, 2006

SeventyMach1 said:
This is wrong. Read the article that you got that first pic from. Here's the link. http://www.specialpatrolgroup.co.uk/spooky/torque/torque.html And here's the quote that says that's wrong:

You are misunderstanding that website author. Just stop for a minute and consider the physics! If you look at the pictures closely on his website you will notice he is using the torque wrench to drive a much longer bar (to multiply the torque) and your equation will work fine.

But, as I have said.... Setups like the picture above DO NOT affect torque readings. I don't know how many other ways I could explain this to you. Torque is a measure of the Force you apply multiplied by the perpendicular distance of the moment arm. It doesn't matter if your extension is 2" long or 3' long, your torque measurement will be the same!

Roland69 · Apr 15, 2006

^^^^ Agreed

txstang84 · Apr 15, 2006

wow, this got way out of hand...

I thought for sure I'd given the guy enough information

cobradvm · Apr 15, 2006

You really need to read the top part of that website. What the guy is actually talking about is using a torque wrench plus an adapter that lengthens the handle of the torque wrench so he can torque bolts that have torque requirements that exceed the wrench that he has. Then your formula is valid.
Here it is again - make sure you read the last part I quoted!

"If, like me you don't have a torque wrench that has the capacity to torque up the Rear hub nuts of the Flywheel gland nut, here is the solution.
You do still need a torque wrench, but only one that is capable of up to 100 lbs.ft. You will also need an appropriate extension.
You can increase the output of a torque wrench by putting an extension between the wrench and the nut in question. Following is an extract from a torque wrench manual:

Before carrying out this process be sure you fully understand the theory. Nuts and bolts incorrectly torque loaded can cause damage or injury. "

JimBowy · Apr 15, 2006

txstang84 said:
wow, this got way out of hand...

I thought for sure I'd given the guy enough information

Tell me about it, I just can't stand the wrong information being suggested.

SeventyMach1 · Apr 15, 2006

Now I kinda realize maybe I am mis-interpreting what this dude is saying. Let me ask you Jim .... in the quote below ... is the guy referring to a crow's foot type of extension, or a regular extension? They did not specify. If they're referring to a crow's foot type adapter ... my formula still stands, but not for a "perpendicular" situation (so I'd be wrong on that part). However, you still can't tell me the torque value won't be changed with a "perpendicular" situation.

If an adapter is attached to the square drive of a torque wrench, the wrench will not give the actual torque indicated by the setting of the handle. A simple formula however, allows you to figure out what the setting should be to deliver a pre-determined amount of torque at the end of any adapter to the fastener.

txstang84 · Apr 15, 2006

maybe this will help....

http://home.jtan.com/~joe/KIAT/kiat_3.htm

cobradvm · Apr 15, 2006

You are still not quite grasping this - the adapter he is referring to in your quote above, is as follows - he has taken a breaker bar, and added a pipe to extend the handle of the breaker bar. Then he has welded onto that extension a socket into which the end of the torque wrench goes - this has effectively about doubled the length of the handle of his torque wrench. This for sure changes your torque values. Any extension that is perpendicular to torque wrench will not!!!

txstang84 · Apr 15, 2006

man oh man, this is getting silly

mach one-if you do not change the "effective" length of the torq wrench, the values will be accurate, if you extend or shorten the effective length, you will have to recalculate based on the equation that you found

DO NOT USE U-JOINT sockets with torq wrenches, use deep well sockets, and DRIVE extensions all you want, they will transmit the torsion (also known as torq) just fine unless you permanently disfigure the tool-which means you're either torqing too much, or using s h i t t y tools

Blandnuts · Apr 15, 2006

The tq rating will be affected if the extension from the socket to the tq wrench is lengthened. Yeah, a 3inch will be minimal, and not an issue.... The formula doesn't take into account for this.

Repostyle · Apr 15, 2006

Okay, the pic above is when the actual readings are different than what's being applied. When the nut or bolt is not directly under the torque wrench head.

Using a breaker bar on the handle will also not effect the torque being applied to the nut or bolt, it will only effect the amount of force needed to apply the torque, meaning, you will "feel" it easier to put the same torque on the nut or bolt. But it will not change the readings on the torque meter. A breaker bar (ie: pipe) effects leverage, not torque.

Using a standard extension adapter that keeps the nut directly under the head of the wrench will not effect the readings, unless the extension is super long and cheap, then it might act like a torsion bar and twist, which will effect the readings.

Hopefully, this will clear all of this up and both of you will see you are wrong

JimBowy · Apr 15, 2006

wow, lots of activity here all of a sudden.
you guys summed it up.

klapdout · Apr 15, 2006

Torque is a measure of the Force you apply multiplied by the perpendicular distance of the moment arm. It doesn't matter if your extension is 2" long or 3' long said:
thats true i just finished the chapter on simple machines in phisics which mainly had to do with different lever arms and torque, so this is drilled inmy skull pretty well atm

extension won't matter at all if its kept perpendicular, course trying to hold a 3' extension straight would be an interesting task

jstang209 · Apr 15, 2006

neva thought this would be a hot topic but thanks for all the info again haha

Euphoric306 · Apr 15, 2006

obviously the original equation given by seventy isn't one for use with perpendicular extensions, because it doesn not take into account the diameter of the extension. a 1/4 inch wide (diameter) extension would flex a lot more than a foot wide(diameter) extension

anyway...

JimBowy · Apr 15, 2006

let it die....

How do u use a torque wrench?

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