Calibrate Torque Wrench Without Any Special Tools

It's a metric Allen wrench.

I could not resist having an opinion on this. Due to the nature of how torque wrenches work, the end result of calibration creates a ratio in the scale. You change the ratio when you adjust any one location, then you only have that one spot where the torque wrench may be correct and it may be out at all other locations. To calibrate a torque wrench you need to check it at 20%, 60% and 100%. You make adjustments as follows: Adjust the low end (20%) using the handle untel it reads 20% of the max scale reading. Then adjust the screw on the side to set the 100% reading. If you had to adjust the 100% you then need to re-check the 20%. If you re-adjust the 20% you again check the 100%. You have to keep this up until you check both the 20% and the 100% without needing to adjust. Then you check the 60%. If the 60% is good you are ok, if the 60% is not good the only way to fix that is to replace the spring and start all over at 20% and 100%. It may have been left under tension for a long time and lost its spring tension ratio. Other wrenches use a different system for the 100%. They use a pivot block instead of the screw and roller bearing inside. Everything is the same except you change pivot blocks with size differences measured in thousands of an inch. The 20% is still adjusted at the handle and the 60% is still the spring tension. To adjust the wrench handle at any set value is to destroyed the Spring Tension Ratio and the wrench may only be accurate to that setting only. All other settings will be inaccurate. The minute you make any adjustment to the wrench you need to recheck 20%, 60% and 100% and ensure the Spring Tension Ratio is still accurate which it may not be. If you adjust the wrench at any one setting you totally change the ratio throughout the handle movement and very likely you have destroyed the accuracy of the wrench in all other locations of adjustment. By the way I have a certificate from Snap On to repair and calibrate torque wrenches as well as calibrate the instruments used to calibrate the wrenches. This will make the wrench unreliable at all locations other then the one it was set at. Take it from a certified torque wrench technician, do not do this. The fact this worked for him and was later tested fine was simply lucky for him but may not be lucky for most of you. Either that or the calibration tech repaired it without telling the customer.

Never use a torque wrench as a breaker bar.

3:31 You actually have your wrench set to 50 pounds at this time stamp, not 40 as you intended to. The little lines that come off the numbers on the left and zigzag down then over to the center line, where it intercepts the center line is actually where you need to set the adjustment. What you did was set the adjustment so that it covers the number 40 halfway, that's not how any torque wrench works or is read.

Finally Found a use for my dumbbells

I lost my shit when you said “breaker bar”....

I almost threw my Tekton wrench in garbage and bought a new one. Thank you!

Be sure to set the torque on the wrench before choosing the length, because if you adjust the torque after you've chosen the length then your measurement will be off (maybe not enough to make a difference, but between the 20lbs and 150lbs on my wrench is almost an inch) so if it's at 150lbs and you adjust it down to 20lbs, that could add an extra inch to your initial calculation.

In fact, they are keys in the Imperial System (inches), the measurement system used practically only in the USA. The adjustment must be made with keys in the Metric System (decimal), which is predominant throughout the world. This is the first time I've seen Halen wrenches in inches...

I did it just like you said and I think it worked, thanks!

Remember from high school = VECTORS.. the torque wrench needs to be positioned HORIZONTALLY. If it is not. THEN the you can't use the formula that you showed. Again = VECTORS. horizontal and vertical . Also. As pointed out by previous viewer you need a set of METRIC hex head wrenches. Spend the money. SAE = inchese; METRIC = millimeters

Smart and simple, thank you.

Get a breaker bar. Save your torquer wrench.

Ideally the bar should be horizontal or you introduce cosine error ( tilted up like this, the distance from the weight to centre is less than the measured length), not a big deal for small angles, admittedly

Thanks so much, the comments are funner to read then the daily news papers... 20min of pure joy!

Wow! I had no idea that calibrating one of these things was that easy! Today, I bought 2 of these. One small one that does 20 INCH pounds to something..... Sadly, I got a defective one. Even at 20 INCH pounds, it's like there no clicking. It just stays solid. So that's going back. LOL The other one, which is almost identical to the one you demo here, I'm not sure yet. But after seeing your video, I just might test it like you did. Thanks for that.

Using a torque wrench as a breaker bar is like using a violin as a hammer.

Thanks again.

Don't you have to calibrate the scale you used to weigh your toolbox?

"I calibrate my torque wrench with my scales". I missed the bit where you calibrated your scales.