Calibrating Torque Wrench.

Do you carry out work with the torque wrench that needs a high level of accuracy when being assembled?

Do you carry out work with the torque wrench that you're being paid for?

If you've answered yes to either of the two questions then you should have had it calibrated annually so get on with it or buy a new one.

If you've answered no to both then just carry on with the same wrench.

Only you can know how much you've used the wrench and how badly you've abused it and they're the factors that matter rather than age when it comes to home use.

you need at least two for normal use, if you don't use them as breaker bars etc they are likely to stay as accurate as is necessary indefinitely.

if you are worried then just rig up a weight system, grip the square drive in a vice and see how much weight needs to be applied to get the torque wrench to click. obviously you need to measure a set distance along the handle and maybe work out a ratio or two. if you stick to foot lbs it is quite easy.

Unless it's been abused or left to rust it should be fine for a lifetime.

When I work in the sircraft industry we had to have ours checked every year but they never needed adjusting.

DIY is the best bet.

Use a socket on a bolt head in a vice Attach a spring balance (from fishing tackle shop) to the end of the wrench and pull. The torque setting should agree with the distanceXforce, e.g ftlbs, kgm, etc.

If in doubt (do fisherman ever lie?) check the spring balance with objects if know weight e.g. the favourite "bags of sugar".

Any wrench that's marked from O has to be suspect.

Teng Tools do a good wrench @ £57.90 RRP

Checking it isn't difficult. Recalibrating if wrong may well be - even impossible.

What are you doing that requires such accuracy? Most automotive tasks don't.

And you simply won't get one device for this range - the lower settings need specialist and expensive tools.

I have had two Norbar wrenches (different ranges) for several years, and they have never yet required recalibration.

Bill

I bought my Norbar one in 1979, I checked it on the test rig when I worked at Millbrook Proving Ground in 1996 and it was bang on. I haven't used it much and the tension is always wound off before it gets put away. I don't think it'll eveer need recalibrating for the very little use it gets.

Lozzo tossed off:

I surveyed their works for aircon maintenance last month

You get some interesting vehicles in there, from all over the world.

Lozzo tossed off:

Ahh, sorry, I wasn't at Milbrook, I was at Norbar in Banbury.

Their works are very small and somewhat unsophisticated for an international company, but their products (from what I saw of them) are top notch. I hope I win this one, although a mate currently has the contract.

You might like to test the accuracy of your torque wrench yourself first. Here is one description of a simple home-made jig and the procedure:

That's not calibrated though, so you don't gain much.

The one I bought is calibrated with certified accuracy in Vernier scale in Newton metres and in kilograms-force metres; not pounds-force feet, I grant you.

But traceable to what?

I can't answer your question, but I know someone who can. :)

I'm an RAF engineer. Our torque wrenches are calibrated every 3 months, and the % error calculated. There is a tollerance beyond which they are withdrawn ( around 3% I think ). Also we are supposed to check the torque on a torque analyser ( meter ) before any task.

Of course I do this working on my car...............

Oh, and how many of us do actually back the wrench off totally after use to avoid knackering the spring?

The Older Gentleman tossed off:

Waves here, too

Religiously. Never once forgotten. Yet.

The message from "Dan L" contains these words:

Particles, here.