pdm
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 posted on 1/8/10 at 10:05 AM |
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Torque Wrench calibration question please
Morning all,
Apologies if this is a really daft quesion but here goes !
I have a new Halfords Torque Wrench with calibration certificate. How long does the calibration/certificate last ?
I don't think I'm likely to use it for a while as I am still stripping my donor - so all undoing than tightening up for now.
The instructions say leave it at the lowest setting (but not beyond) which is how it was set when I got it so it will stay this way until I come to
use it in anger.
So does it become less calibrated through use or just time and how do I know when I need to get it recalibrated ?
thanks all
Paul
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rayward
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| posted on 1/8/10 at 10:13 AM |
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the only problem you will get is if you leave the spring compressed for a long period of time,
BUT, tbh i wouldn;t trust a calibration certificate from halfords anyway !!
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Hellfire
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| posted on 1/8/10 at 10:17 AM |
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1 year.
But not worth the paper they are written on. To get it Certified would cost possibly more than the wrench itself 
Steve
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jollygreengiant
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| posted on 1/8/10 at 10:17 AM |
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Generally speaking, callibration certificate are usually valid for a year.
Beware of the Goldfish in the tulip mines. The ONLY defence against them is smoking peanut butter sandwiches.
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MakeEverything
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| posted on 1/8/10 at 10:19 AM |
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You dont need a calibration certificate unless putting an aircraft together, or working on a production line.
Other places ive seen them as "Requirements" are where the assembly or maintenance of equipment needs to meet an ISO or British standard.
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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Stott
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| posted on 1/8/10 at 10:20 AM |
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It will remain accurate enough for a lifetime of use DIY usually, so long as you wind the spring off after use.
The calibration of the halfords ones is very good, they are made by Sykes Pickavant and are very accurate. The cal cert is from the manufacturer and
not from Halfords.
We submit our (quality but not SP) ones every 12 month for re-cal in work and they seldom need adjusting, and they get abused TBH
DIY, it should be good for ages
HTH
Stott
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les g
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| posted on 1/8/10 at 10:39 AM |
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yep as said above
if you are an ISO 9002 registered company then all wrench,s gauges etc need calibrating every year to maintain the ISO thingy.
and torque wrenchs rarely go out of spec. especially if stored with spring wound off
cheers les g
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BenB
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| posted on 1/8/10 at 10:40 AM |
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I just check mine every now and again against my torsion bar springy type torque wrench.
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interestedparty
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| posted on 1/8/10 at 10:49 AM |
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I keep meaning to make a fixture to test mine but haven't got round to it you. Probably never will.
Have been thinking about getting on of those digitale units that fits between the wrench and the socket and makes a noise when the torque is correct,
rather than relying on a spring and detent mechanism.
As some day it may happen that a victim must be found,
I've got a little list-- I've got a little list
Of society offenders who might well be underground,
And who never would be missed-- who never would be missed!
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pdm
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| posted on 1/8/10 at 10:53 AM |
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So store it unwound and it should do me for DIY.
excellent - thanks very much everyone.
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907
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| posted on 1/8/10 at 11:10 AM |
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Hang a 10lb weight on 2 foot wrench and it will click at 20 ft/lb.
Job done, calibrated.
Paul G
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Stott
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| posted on 1/8/10 at 12:08 PM |
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But then you need a callibrated scales to weigh the weight in order to callibrate it so you can use it to callibrate the wrench 
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RichieHall
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| posted on 1/8/10 at 12:27 PM |
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The calibration will typically last for one year, but really isn't worth worrying about.
In the aerospace world wrenches aren't calibrated at all, they are just checked against a calibrated torque analyser before use, the analyser
will cost you a couple of hundred quid!
Rust is lighter than Carbon Fibre!
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indykid
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| posted on 1/8/10 at 01:47 PM |
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i checked mine from screwfix using an atlas copco acta unit at work. it was a country mile out, especially at the bottom end. about 10% low at 90lbft,
40% low at 30lbft.
when i did an r&r study, the norbar clicker wrenches were by far the most repeatable, even the ones that were yonks old. on our assembly lines, we
use electric wrenches with inbuilt transducers though.
tom
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v8kid
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| posted on 1/8/10 at 02:15 PM |
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Bills Tool store The Barrows Glasgow have ex MOD torque wrench calibration machines for £20.
Best hurry if you want one
You'd be surprised how quickly the sales people at B&Q try and assist you after ignoring you for the past 15 minutes when you try and start a
chainsaw
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MakeEverything
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| posted on 1/8/10 at 03:54 PM |
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quote:
Originally posted by v8kid
Bills Tool store The Barrows Glasgow have ex MOD torque wrench calibration machines for £20.
Best hurry if you want one
Yes, but they themselves are calibrated....
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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907
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| posted on 1/8/10 at 04:03 PM |
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quote:
Originally posted by v8kid
Bills Tool store The Barrows Glasgow have ex MOD torque wrench calibration machines for £20.
I'll do 5 bags of sugar and a bit of string for £19.
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:{THC}:YosamiteSam
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| posted on 6/8/10 at 09:11 AM |
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use a digital or needle guage dial guage on the fixing as well. We use at work digital torque stations. They are sent away to be accurately calibrated
then all our break back wrenchs are checked on those every day. Long winded for the home user. You can buy quite cheaply dial guages to test what
torque a fixing starts to move. Read the guage the moment it does. Then check it against what the torque wrench click at.
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