Torque Wrenches

[6869704X4]

Well Rip,
What happens to a 20" torque wrench set at 200 when you add a 5" arm?
Like my Grandaddy said, "you dont work for your tools, you make them work for you".

[fatfords]

ScottH,
Look in the yellow pages under "calibration." Here in Fort Worth, we have 10-12 listings. At my work, we assemble aircraft parts, so all the torque wrenches have to be calibrated every 6 months (depending on usage) to meet FAA and customer requirements.
There have been many good suggestions for storing your wrench. Follow them all and it will help, but may not prevent errors.
IMO, the beam type is the way to go. We use the clickers at work, due to the repetition and,as was mentioned earlier, viewing the markings is not always easy. We pay ~$40/wrench for calibration.

LOL,
Kent

[RipMeyer]

Originally posted by 6869704X4
[B]Well Rip,
What happens to a 20" torque wrench set at 200 when you add a 5" arm?

Well..... if its a 250 ft lb for example and you add a 5 inch arm on the end and you have it maxed out on the high setting trying to get 300 ft lb`s. I would say you just damaged a $250 wrench.

If you change the pivot point you really have no idea what kind of torque you are applying. You example is different than what the drawing and my reply was about.

[6869704X4]

Rip,
Using your example of a 250 pnd wrench and its set at 200 how are you going to ruin the wrench?
You pull it untill it clicks and then stop. The added length of the arm puts more torque on the fastener. Its because you have more leverage. The wrench doesnt even feel this.
I used 200 as an example because COBALT said he got a 200 pounder.
And my example is exactly what the drawing says. What happens to a 20" torque wrench set at 200 when you add a 5" arm. You get 250pnds of torque at the end of the arm when the wrench reads 200.
Plug in the numbers and see for yourself.

[RipMeyer]

With out a doubt the more leverage you have the capacity of the wrench is greater, However the internals and external of the wrench are designed to only handle a certain amout of torque. If you apply more, the wrench could be damaged. Trying to exceed the max setting of the wrench with a cheater pipe is not recommended.

The wrench does "feel" the torque at the end of the wrench, if the torque is applied to the fastener it must also be applied to the wrench at some point (the end). If its a clicker/rachet type this is not a good thing. The wrench can only handle so much. Where do you draw the line?


The formula listed is for odd type adapters such as a crows foot.
It can be found on most of the manufactures web sites.

The correct way to get more torque out of a smaller wrench and not exceed the rating of the wrench is to use a multiplier and that is quite different than what we are talking about here.
Handtorque multipliers incorporate an 'epicyclic' or 'planetary' gear train having one or more stages. Each stage of gearing increases the torque applied by a factor of 5, allowing multipliers in ratios of 5:1, 25:1 and 125:1





if you are interested in multipliers Click Here

[RipMeyer]

Here is a very good way to to what you are talking about.
However it is slightly different and no damage will result to the wrench as the torque applied is not on or even near the racheting head.
However his equipment is VERY ROBUST.

http://www.specialpatrolgroup.co.uk/...ue/torque.html

[6869704X4]

Unless Im completely whacked Im sticking by what I learned in tool school.
If you set a wrench to 200 and pull untill it clicks, then stop, the wrench only felt 200. Does this make sense? Or was I taught wrong.
I was just trying to give COBALT somthing to work around having to buy a new high dollar wrench.

[COBALT]

Thanks everyone for your input. I think I know what to do...

RipMeyer: You're assuming that force on the wrench head stays constant. It doesn't. The longer bar requires less force hence constant torque, since torque is defined as the rotational force times the moment arm.

In this application since the wrench detects torque set at specific levels (we assume that's constant) then it doesn't matter how long the moment arm is. Less force will ultimately be needed to reach the specified torque. It would only damage the wrench if we ignored the torque settings we placed on it, which would also destroy the fastener we were trying to turn, which would also happen regardless of the increase in moment arm.

If your logic were correct then we would have to limit the useage of torque wrenches to people who could only apply a specific amount of force, because people with more mechanical leverage could damange the wrench.

[mikep]

"If your logic were correct then we would have to limit the useage of torque wrenches to people who could only apply a specific amount of force"

That would be my brother Russell for whom I have had to install thread inserts, apply EZ outs and weld cast iron several times to repair "Russ-torqued" fasteners . Russ weighs in at close to 400 lbs and has arms the size of my legs.

[COBALT]

sheesh...needs to listen for the "click", or read the guage every once in a while.

[RipMeyer]

I stand corrected. I thought 6869704X4 was talking about adding an extension to the handle part of the wrench. If that were true the end of the wrench(where the fastener is) feels every bit of the torque and it could be damaged. Its kinda like using you 3/8 drive 6in rachet with a long extension on the handle to torque 250 ft lb`s. It wont handle it. The gear in the rachet will break or strip.

[COBALT]

...or at least bust the extension. I think the reason you two guys got your wires crossed is the useage of the word "handle". Oh well...

Someone posted a message a while back about what's the best: going from 1/2" drive to 3/8" or 3/8" to 1/2". I remember telling someone that the answer was simple: 3/8" to 1/2". I've broken an adapter before that reduced a 1/2" drive wrench to 3/8". Twisted the peg right off the adapter. MUCH more difficult to break a 3/8" drive wrench to 1/2" adapter...similar discussion.

[6869704X4]

Let us know what you wind up doing. I have access to a MAC tools 250 pounder. I know that doesent help you but was thinking that Autozone will loan tools. Wonder if they have a wrench big enough for ya.
Also, thanks for the translation. I was wondering where the disconect was too. Sorry about the confusion Rip.