How to Check the Calibration Accuracy of Your Torque Wrench (Video 2)

[The47Ronins]

Awesome, awesome video! Thanks you!!

Where is the Holiday Inn you stayed at, I need to check in!!!

LOL!

[dial2fast]

@The47Ronins LOL!! Thanks for watching.

[terry218e]

Very Informative Video, Very well done!

[dial2fast]

@terry218e Thank you for your comment and thank you for watching.

[split150]

Great vid, thanks for making it. Tons of great info.

[dial2fast]

@split150 Thank you for the comment and thanks for watching.

[mario102395]

where did you get all this wealth of knowledge from. DEVRY???

[dial2fast]

@mario102395  I stayed at a Holiday Inn!!

[vdjun13sur13]

i just got me a used Snap-On 12Inch QJR3250A and the previews owner told that he used it few time.... in cosmetic terms the wrench is not scratched or that it has been dropped. this video has helped allot and thank you for uploading it.

[wingerrrrrrrrr]

The weight of the wrench itself would result in it clicking at a higher setting than expected, but if you stick with testing values high up in the scale, the error will be less significant. You could minimize the effect if you place the wrench in a vertical position rather than horizonal, and use a spring scale like the kind used for weighing fish (don't use the tall tale versions-) to apply the force.

Then the weight of the wrench won't matter, and the only error would be the scale accuracy

[KozmykJ]

How much difference does the weight of the wrench itself have on the calibration?

[57gemini]

So, if you have a 12 inch long wrench, and apply 100 lb, then you'll have 100ftlb.

If you have a longer wrench, you will have to reduce the weight on the handle, to get the same torque on the socket. Thats where the calculation comes in.

But you say that you divide with 12 to get ftlb, is that right?

[dial2fast]

If your torque wrench was EXACTLY 12" from socket to the middle of the handle, then you can just hang the 100lb & check for 100 ft/lb. Most torque wrenches are not 12" (= 1 foot), so you have to do the math. My 1/2" torque wrench from socket to middle of handle is 18" (Ex: 18" X 50lbs = 900 in-lb, BUT 12" X 50lbs = 600 in-lb). As you can see, correct length is critical in finding the torque you are testing. Since the length is inches, to get foot-lb, divide by 12 (there are 12" in 1ft).

[57gemini]

@dial2fast

Thanks for your reply. Very helpful.My wrench broke, and i'm just getting new parts. The rachet mechanism. And there was a thing about the adjustable handle too, so I had to take it appart. But with the weigt on the handle, it seems to turn out OK. I consider it calibrated.

Thanks again

[dial2fast]

@57gemini I am glad this video helped you. As long as you can get an idea of how close to accuracy your wrench is, then it's adequate for most jobs. Even a brand new torque wrench out of the box has +/- 4% tolerance. If you use the lower torque wrench range, it can be as far out as +/- 10% or more. My method of checking is not as accurate as sending to a lab for calibration but it's good enough for most DIY'ers.

[57gemini]

@dial2fast

Hi, thanks again for your your reply. It's a good thing to understand what we are dealing with, and how things work. That's why I take things appart, and put them together again.Have a nice day.

[57gemini]

Or, is the calculation for how much weight to hang on the handle, to get the moment of force, set on the scale, on the senter of the square for the socket? You say that , to get the foot lb, you must divide with 12. But won't you get the inch lb then? Again, correct me if i'm wrong.

[57gemini]

what is the point with the calculation? Just hang the known weight on the handle, and if it clicks on the preset mark, you know if it is right set up. Am I right or what?