How to perform your own torque wrench calibration testing

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Galactic Greyhound
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How to perform your own torque wrench calibration testing

Postby Galactic Greyhound » Thu Dec 02, 2010 10:08 pm

To check your torque wrench, see link;

http://www.gl1800riders.com/forums/show ... p?t=232615" onclick="window.open(this.href);return false;

Thanks to the Honda GL1800 Goldwing Forum.
Ced.

R1100RT 1996.
Sent by Boson Quantum Transmission from the Starship 'Galahad'.
http://www.researchgate.net/publication ... ing_bosons" - It works!

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peter
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Re: How to perform your own torque wrench calibration testin

Postby peter » Fri Dec 03, 2010 12:02 pm

Although I haven't a torque wrench, it seems a good way to check it.

When you want to take the mass of the wrench into the calculation,
Take the half of the wrench's mass, add it to the mass of the weight hanging on the string and use that for calculation.
You will still be a bit off as you only want half of the torque head's weight, but thats more difficult to do.

A comment on why it's important where to hang the string.
The wrench doesn't care, that's correct.
It measures the torque that happens at the rotationpoint, not how you apply it to the lever.
However, you are checking it.
As torque = length x weight, you need a length and a weight.
For calculation take a conveniant lenght, it doesn't need to be on the grip, but you need to measure it exactly.
Also take a conveniant weight, either conveniant as it's laying around or one having a weight easy to calculate with.
The formula would be:
Torque = (half the mass of the wrench + mass of the weight ) x measured length

If you want multiple tests, you can either change the weight or the length or both, as long as you change these in your equasion.
Peter
Used to own a 1982 R100CS, but it was destroyed by a truck.
2003 R1150R + Touratec Alu boxes + Gimbel fairing + MC Cruise Cruisecontroll

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Galactic Greyhound
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Re: How to perform your own torque wrench calibration testin

Postby Galactic Greyhound » Fri Dec 10, 2010 7:15 pm

Hi Peter,

I quite agree with your comments.

I didn't have a suitably calibrated weight handy so I used water in a builder's bucket. I added the weight of the bucket (by weighing) to the weight of the water it contained (by calculation) to get the total weight. Here is a handy link for calculating the weight of water using various scales: http://www.onlineconversion.com/waterweight.htm" onclick="window.open(this.href);return false;

On looking further into the 'torqueing' principle of clamping two pieces together, it is a real 'can of worms'! You will get different results if the theads are lubricated than if they are dry. Also, different lubricants will give different torque settings! There can be a difference of 30% between dry and lubricated torqueing i.e. a 'dry' torqueing to 30Nm could result in an actual torque clamping of around 40Nm if the threads were lubricated!

It appears to me that the torque readings given in the maintenance manuals are usually for 'dry' fitting unless otherwise stated. However, I have always assembled with a lubricant on the threads with the view that it helps prevents corrosion and seizure thus making future disassembly a lot easier. So should I be making an allowance for lubricated threads? The whole thing looks a bit ropey so I wouldn't worry too much about not having a torque wrench as long as you are sensible when tightening fasteners especially where aluminium alloy threads are involved.
Ced.

R1100RT 1996.
Sent by Boson Quantum Transmission from the Starship 'Galahad'.
http://www.researchgate.net/publication ... ing_bosons" - It works!

gavreeder

Re: How to perform your own torque wrench calibration testin

Postby gavreeder » Wed Mar 05, 2014 11:28 am

I use a spring balance (newton meter) and turn a bolt in a vice. Pulling on the spring balance in a horizontal direction means the weight of the wrench is not a consideration. You have to measure the distance from the center of the pivot to the nearest mm. This works well for wrenches up to 20Nm unless you can get a spring balance greater than 100N. Before I owned a torque wrench, I sometimes used a newton meter in conjunction with a breaker bar and a ruler.


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