Easy Torque Wrench Calibration Test

you must take into account the weight of the wire and the weight of the wrench itself adding to the torque. which is why it clicked at 40. because the actual weight was slightly more than you calculated.

at last, someone who's working in metric rather than imperial ! (my recently purchased wrench is metric only)... and we did go metric in the UK when I was still in nappies.....many, many years ago.

I've done this for adjusting a Toyota Hilux 2.8 L diesel engine belt to the workshop manual spec. The book reads something like "apply an 'X' Nm force to deflect the belt by 10mm (or thereabouts)". There is obviously a special tool used by the factory to do this. I thought about this for awhile and then realized that elementary 'A' level physics class on the mechanics of levers does come in useful here ! With a little bit of ingenuity and calculation adjustment, a spring scale from the local hardware shop came in very useful.

Just realized I've never watched a British auto advice YouTuber before. Good video ty

I love you for this - so simple. I can't believe I never thought of this. Brilliant.

The only place weight can be accurately applied is centered in the designated grip area; moving it along the shaft is NOT a simple linear leverage effect, as the release/click depends on internal flexion of a beam. Weight known to be accurate can be added slowly, but only at the correct place on the handle.

Thanks! Mine was of by more than 10 Nm. I fixed it by inserting a penny between spring and other metal parts inside the tube. Now it is of by only ~2Nm, which is great!

Hello, This is the best way to understand the calibartion procedure, because the initial formula help a lot!! nice job

Nice explanation. I watched it twice, the penny dropped the second time, and I learned something new today !

Put weights, zip tie or wire AND wrench on a scale until 20lbs. is reached. Put wrench drive in a vice so the wrench sticks out horizontally. Measure out from drive towards the the handle 1ft. and mark it. Set wrench to 20 ft/lbs. Zip tie or wire the weights to the mark but dont let go. Slowly lower the weights til it clicks. If it clicks too soon or doesnt click, it needs recalibration. I got it.

Instead of clamping the square drive directly in the vise, it'd be better to attach an extension to the wrench and then clamp the extension in the vise. That way, all four sides of the drive are being used and you won't mar the drive. If your vise doesn't have slots/teeth to hold round shafts, there are jaw inserts (magnetic or screw on) that allow clamping of round shafts, and if you're doing a lot of vehicle work, you're going to need them at some point anyhow.

finally someone who showed in metric. I cant go down to 40NM but i doubled and at 80NM the luggage showed 19+(not very precise cheap luggage scale) kg so i am fine. It was a cheap wrench.

the pivot point is NOT the point where you attach the socket. the pivot point is that little circle few cm towards the handle. if you move the weighs around the handle, you are actually "changing the torque setting". every torque wrench has a marking which shows where you should ideally apply the force in regards to the pivot point so that the torque to the socket is correct.

It would have been a good idea to weigh the weights first, with a digital scale, to see if they are accurate.

Very well explained sir.

I worked in a machine shop governed by aerospace parameters for nearly everything on the shop-floor ... we used Bacho torque wrenches , they had monthly calibration. Nearly every one failed and was cut in half and skipped after 3 months! It was a very high usage environment.

perfecto lo voy a hacer

Thanks for the nice to the point video. I don't think it really matters metric or imperial so long as your torque wrench does what it needs to do. I sort of cheat in that all of mine have more than one force measurement listed.

The screw on the shaft is hiding a hex bolt that you can use adjust the tension and calibrate the wrench.

thats more accurate than new snap on digital one.