Calibration on torque wrench ????? How often

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Mikekitts81
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Calibration on torque wrench ????? How often

Post by Mikekitts81 »

I have had a few nuts and bolts thread on me lately which lead to me not having forks as the holes threaded out and I think it's down to torquing them to much as this as happens more than once lately so iam thinking it's my wrench now I no a lot of top end garages etc have there torque wrenches calibrated hence the stickers on there's like this
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Screenshot_20171221-141116.png (411.04 KiB) Viewed 4446 times

So what's the lifetime of a torque wrench does it need replacing every few years etc depending on how much you use it or recalibration or is my wrench just knackered .. Price wise I can get a new one for 30 quid there's even cheap screw fix ones for 20 quid ... so its not really worth while having it recalibrated
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garyboy
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Re: Calibration on torque wrench ????? How often

Post by garyboy »

Mmmm .. looks like they should be calibrated but probably only by reputable garages I would guess? to avoid claims?

I got 2. One 3/8 for lower force and one 1/2" for bigger forces. A second one can enable a check on the first one?

and cheap enough.
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Re: Calibration on torque wrench ????? How often

Post by Richard Simpson Mark II »

I purchased a cheap new one...I won't name the make, but it seems to be one that is sold under several different brand-names.

I believe it under-read significantly, straight from the box, as it over-stressed several fasteners being tightened to the vehicle manufacturers' recommended figure before that figure was reached. The same product was reviewed by RIDE magazine, which reported the same issue.

These are good

https://www.norbar.com/en-us/About-Us/I ... ons...made in UK too.

You can get them in Halfords...and you won't find me recommending Halfords tools often.

Regarding recalibration...it depends on how much you use and abuse the tool. It's not a breaker-bar, but some people seem to think it can be used as such. Treat it as a precision instrument, follow the instructions for use and storage, and I wouldn't have thought that a quality one would need adjusting in 'hobby' use.

It's a different matter for those used in truck workshops etc.
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Re: Calibration on torque wrench ????? How often

Post by vRSG60 »

Halfords professional range are very good and come with a lifetime guarantee.
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Re: Calibration on torque wrench ????? How often

Post by Richard Simpson Mark II »

I've been told they are NorBars...and made in the UK
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Re: Calibration on torque wrench ????? How often

Post by bill_qaz »

The biggest problem is not winding them back to zero before putting away. It compresses the spring and makes it inaccurate.
Workshops have them calibrated anualy usually to comply with franchise standards set by the manufacturer. or ISO compliance.
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Re: Calibration on torque wrench ????? How often

Post by garyboy »

all interesting stuff 8-)
of course, a brilliant mechanic like maself does not need a torque wrench ..
8mm .. only just pinch up (feels like it will come loose, but is ok) .. saves the thread.
10-12mm .. just one or two finger tight .. pinch up plus a slight more force.
axle nuts .. quite a fair force, but not too much, enough not to come undone.

see? ... easy !! :lol:


ps .. I am very strong in my right hand (for some reason) ;)
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bowber
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Re: Calibration on torque wrench ????? How often

Post by bowber »

Easy to calibrate yourself if you have some reliable weights.
Clamp the sqr in a vise with the handle horizontal. Hang a known weight at a measured distance, a bit of calculation and you've calibrated it.
I've never calibrated mine though.

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Re: Calibration on torque wrench ????? How often

Post by Famous »

How often should they be calibrated

Depends on the standard you are working to.

It won't pay to calibrate an old poorer quality instrument

If you buy a good quality one it will come with a cert

You can always check your wrench by doing a small bit of Maths and using a weight on a bar at a definite distance

Always unload the spring tension when not in use

Don't use one that you think is wrong
Two wrongs don't make it right
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Hugh
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Re: Calibration on torque wrench ????? How often

Post by Hugh »

Greetings,

When I first started in the motor trade the larger dealerships had a special tool store and such items were tested every time before being allocated to a technician. Now that does not generally happen because of obvious cost cutting but the torque wrenches are still tested annually and certificated as the questioner showed in his photo. The fear of litigation; insurance claims and such are too great to risk.

I moved onto aircraft with the RAF and we had to test any torque wrench before and after each use. Every tool had its own reference number and log book into which was recorded things such as issue date and time; who used it; the aircraft ID; date and time of return. Pity help anybody who did not clean and reset an item fully back to zero after use or replace it in its correct storage location :o

One aspect we tend to forget is that over time the strength of the material deteriorates and typically corrosion takes effect to weaken the fastener and its housing. Applying grease to threads helps to protect from corrosion but as it lubricates it is possible to over stretch the threads for the same torque figure.

For home use a quality item such as a Norbar is fine so long as you look after it. Torque wrenches are for clamping and tightening, they are not for releasing as a standard bar will suffice. Ratchet wrenches are not for initial release either, they are a speed tool. The old style static pointer and moving arc type are not accurate for most modern applications.

One problem for us owners is that previous tightening might have been incorrect or the fastener replaced with a non standard item. Some items might require a torque setting plus a stretch measurement, although rare on motorcycles. I tend to slightly under tighten items such as drain plugs or caliper bolts preferring to secure the bolt or nut with lock wire, but even here there is a 'nack' or it will not secure properly :roll:

Take care of your tools and they will take care of you :lol:

TTFN

Hugh.
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