Torque wrench calibration.

The Norbar company in Banbury just quoted me ?36+vat to calibrate my North Bar Torque wrench!! probably about ?10 postage on top of that.

[NedSVS]

If you have looked after your torque wrench and not abused it, then you should have little doubt about its accuracy! Torque wrenches that get used heavily or may have been missused may require recalibration, but with the light use most of us give them it should be fine. Do you have any good reason to doubt its accuracy?

[yorkie_chris]

Not too complicated to build a widget to test it.

Originally Posted by yorkie_chris

Not too complicated to build a widget to test it.

How would one go about that YC?

Originally Posted by NedSVS

If you have looked after your torque wrench and not abused it, then you should have little doubt about its accuracy! Torque wrenches that get used heavily or may have been missused may require recalibration, but with the light use most of us give them it should be fine. Do you have any good reason to doubt its accuracy?

Blimey! I didn't expect the headmaster bit! Since it is about 40 years since I bought it I thought I should get it calibrated!

And I should add that it reads 4 - 5% lighter than my mate's new Draper over most of it's range.

Originally Posted by simesb

How would one go about that YC?

Yes, please don't keep it to yourself

[embee]

Originally Posted by ejohnh

.... it reads 4 - 5% lighter than my mate's new Draper over most of it's range.

It's probably right then!

Seriously though, I have a Britool with a calibration which showed it to be better than 2% across the whole range.

I cross checked a Sealey wrench by linking them directly and setting one at a figure and adjusting the other until they would click at the same time, and the Sealey read typically 5-10% higher than the Britool most of the time, for example the Britool at 30Nm corresponded to the Sealey reading 32Nm. At least this is on the safe side regarding overtightening.

I had the opportunity to get mine checked again where I was working last year, still OK.

1 Lt of pure water is 1 kg, so provides 9.81 Newtons force.
Put exactly 3 Lt of water at 1m and you have 29.4Nm give or take a bit, plus an allowance for the container and lever. Etc.

[yorkie_chris]

Originally Posted by embee

1 Lt of pure water is 1 kg, so provides 9.81 Newtons force.
Put exactly 3 Lt of water at 1m and you have 29.4Nm give or take a bit, plus an allowance for the container and lever. Etc.

+1

All you need is a bar with a half inch hole in it (or a 3/8ths one), make it a meter long and hang weights from it or maybe attatch a gauge.

I attached a gauge and now it says 14.6 psi ???