does using a cheater bar on a torque wrench change

[WhyMe]

its readings?? have a couple that will read up to 175#. unfortunately, due to the length of the handle, i find it hard to torque things up like axle nut and such which require a high torque.

i have never put a cheater on it. will putting a cheater on it change the reading?

 

[Colt45ws]

Yes. There are ways to recalculate the torque value, though.
M1 = M2 x L1 / L2

Where:

M1 is the torque setting of the wrench.

M2 is the actual torque applied to the nut

L1 is the normal length of the wrench

L2 is the extended length of the wrench


Normal length is from the center of the drive, to the center of the handle. Some torque wrenches even call out the center of the handle as the load point.

So, lets say you want 160 ft lbs and have a wrench with a 24" length and you add a 12" cheater.
160x24/36 = 106.66666666666

 

[justinf89]

You will apply more torque but the torque wrench will still click at 175. Be careful though because if the bar is too long you may not notice the click and zoom right past 175 although unlikely unless your mad strong. Then you wouldn't be asking in the first place

 

[suspiciousmind]

Colt45ws' response would be accurate for the calibration procedure or verifying the accuracy of the torque wrench.

In application, the wrench will let you know when the proper torque is achieved at the bolt/nut regardless of the length of pipe you add to the handle.

 

[OB4x4]

No,the torque wrench will read the pressure that is applied to it at the handle regardless of the length of any cheater bar on it.

Colt's calculations are correct if you were to recalculate or recalibrate given a known torque value at the end of an extension of given length.

 

[scurvy]

No, it will not change the torque at which the wrench will click... but you will likely be hard pressed to feel when it does click if you've got a cheater pipe on it. The wrench does not know nor does it care how long its handle is, or at what point you are grabbing it.

Colt's example is valid only for calibrating a torque wrench by measuring the amount of applied force at a specific distance from the axis of application.

For medium-high torque fasteners on our metal forming presses, we have a 3-piece Snap-On 3/4" drive torque wrench - 200 to 1000 ft-lbs range. We nicknamed it 'Excalibur' as when assembled it's nearly 5' long and must weigh 35 lbs.

 

[Colt45ws]

Yes, I did a bit more research and found that my calculation is based on an extension on the head. I cannot delete my post anymore, or I would. I withdraw it, regardless.
I took the calculation from the first website I found, which didnt have a drawing of what it was depicting, just a java app which is disabled on my machine.
So...I looked around a bit more and found a site with a drawing of a long crow's foot. And then I remembered it is on that side of the wrench that it matters.

TL;DR, Its too late, I no brain right. Sleep teim.

 

[cptbarkey]

gain some weight and sit on it! wrong answer but thought it might be funny anyway.

 

[another Todd]

Originally Posted By: suspiciousmind
Colt45ws' response would be accurate for the calibration procedure or verifying the accuracy of the torque wrench.

In application, the wrench will let you know when the proper torque is achieved at the bolt/nut regardless of the length of pipe you add to the handle.


+1

 

[WhyMe]

Originally Posted By: cptbarkey
gain some weight and sit on it! wrong answer but thought it might be funny anyway.



i weigh less than the max on my torque wrench. LOL

 

[scurvy]

Originally Posted By: WhyMe
i weigh less than the max on my torque wrench. LOL


Your TORQUE wrench likely does not have any WEIGHT marked on it... torque and force are different units!

 

[doitmyself]

I wonder why torque wrench manufacturers put this in their literature:

"Use of a "cheater bar" will result in an inaccurate reading and can possibly damage the wrench"

http://www.cditorque.com/ under "torque facts"....safe and proper usage.

 

[ChuckBerry]

Originally Posted By: Colt45ws
TL;DR, Its too late, I no brain right. Sleep teim.


Ha this made me laugh