seeing as the Torque Wrench has become the latest must have tool over the last few years, does anyone ever get them calibrated? If they are not accurate then whats is the point
Check them yourself with a tape measure and a known weight or pull-scale.
1 Newton is approximately 0.1kg iirc
Our workshop torque wrenches get checked for calibration every 6 months, car workshop, 3/4 drive for hubs/crankshaft bolts, 1/2 drive for suspension/wheel bolts etc, 3/8 drive engine stuff, 1/4 drive wee fiddly bits, torque screwdrivers etc probably 20ish items and only remember one 1/2 that has failed calibration, it had been left outside in the rain. All good quality brands
No, never had any of mine calibrated, but probably not a terrible idea. Good consumer torque wrenches generally come pre-calibrated to +/- 3% My employers have just sent me on a course that covered this subject. One take-away from this was that torque wrenches shouldn't be stored backed off all the way to zero & should only be backed off to the minimum value that the wrench is specified for.
Just thinking about Stanley's post. Might give this a go.
Never had mine done, but have debated it.
There's a big tool shop that does it up the road from me so I don't really have an excuse.
Are they likely to go out of line from more use or less use? Mine hardly gets used apart from the odd change of stem etc.
why so davesport?
ive always been told to completely back off
Don't know why, but instructions on my Norbar say to just back off to lowest value and not completely off.
why so davesport?
ive always been told to completely back off
Most wrenches will go back to the minimum value then a couple of turns more (depending on the type/manufacturer) Generally, it won't hurt taking back to zero if there's a hard stop, there's always going to bit a little bit of tension on the spring. But, if you try and force it you can sometimes disengage the cam. You may be lucky and it will re-engage when you wind the tension back on. You may not and it'll have to be stripped down and rebuilt then recalibrated.
You can check them yourself, but it's a ball ache as the handles aren't built with a notch to ensure you have the weight or force gauge in the right place as you apply the weight.
Are they likely to go out of line from more use or less use? Mine hardly gets used apart from the odd change of stem etc.
The more use it gets the more likely it will drift - but it will rarely drift outside the general tolerances of +/-4% of reading unless you're using it as a Birmingham screwdriver. 🙂 I've not used mine for several years, had it tested last week and it's fine - though it's s screwdriver and has a +/-6% tolerance of reading.
Gutted I don't work in the industry any longer - I've calibrated them for folks on here before for cake 🙂
I recently checked my 40 year old BEDFORD 1/2 torque wrench.
(The place that I am currently located has a calibrator mounted on a steel wall pillar in the workshop area, and that the device has just been away for calibration).
Always backed off to zero.
At 3kg/m setting = 2.5
At 9kg/m setting = 8.1
At 15 kg/m setting = 13.9
So not wildly out after 40 years DIY use.
Made an adjustment
At 3 = 2.6
At 9 = 8.8
At 15 = 14.9
Happy with the results.
Not to sure how to check a 1/4 drive as the calibrator is a 1/2 device.
Will need an adaptor of some sort.
why so davesport?
ive always been told to completely back off
I've always wound mine back to zero. I'll have to have a rethink.
At 3kg/m setting = 2.5
At 9kg/m setting = 8.1
At 15 kg/m setting = 13.9So not wildly out after 40 years DIY use.
Hang on. Your torque wrench is accurate only to +- 16% on the lowest setting and that's "good enough"? 🙂 I'd suggest you could get as close without one with a bit of practice.. 🙂
The problem would be that all that practicing would make your muscles stronger each time so you would be chasing a moving target 🙂
Hang on. Your torque wrench is accurate only to +- 16% on the lowest setting and that’s “good enough”? 🙂 I’d suggest you could get as close without one with a bit of practice.
I think most home mechanics use one to get the right magnitude of torque rather than going for a precision engineered torque of 5Nm+/- 0.01. Basically we want stuff to be tight enough but not too tight and for most bike parts that's a pretty big range - it's always tempting to give stuff an extra nip when doing it by hand and the torque wrench is just a way of saying "no, that's fine, step away from the bolt now otherwise your future may hold an afternoon of drills, dremels, swearing and spending"
ur torque wrench is accurate only to +- 16% on the lowest setting and that’s “good enough”?
one should never be at the extremes of range anyway.
Bought a Sealey wrench ~10 years ago, never calibrated since. In fairness, it doesn't get much use, besides when I play with my carbon Knuckleball bars or Selcof seat post.
Acratork, great tool https://www.radwell.co.uk/Shop?source=GoogleShopping&IgnoreRedirect=true&ItemSingleId=104434502
one should never be at the extremes of range anyway.
It's fine to use them at the extremes of the range if you're within the stated range of the tool and the calibration results are acceptable.
Cheeky edit *in the home workshop, in industry I've never seen an R&R study that's said it would be an issue (Torque is a PITA for R&R anyway) but your QMS may say otherwise.
The torque wrench is only really used for wheel nut torquing on car alloys, in the region of 11 to 12 kg/m so range at the top end of the scale is around 8% accuracy.
Like I said good enough for that application.
Further to the above & with a bit of Googling it got me interested enough to have a look at the torque wrenches I've got laying around. Three Norbars that cover from 10-200Lbs/ft, a Cyclo 3/8 drive 2-20Nm & an ancient Britool 10-50 Lbs/ft that I bought 40 years ago to work on a motorbike. Despite its age it's always been boxed & stored backed off.
Using some simple arithmetic it's easy to work out the correction factor if the torque wrench isn't 12 inches long. The luggage scale I used was within half a percent against a known weight. There's no maximum hold function on the scale so I had to watch the readout as the load increased. All tested at the mid point on the torque range.
The three Norbar wrenches all within 1.5%, all breaking slightly early. The Britool was over-torquing by 16% The Cyclo which I think cost £20 was as close to spot on as I could tell according to the scale. Don't know what's happened to the Britool one as it's always been treated with kid gloves. The whole mechanism is exposed & I'm wondering if the lubrication has dried up.
I'm away to tighten some nuts. D.
I think most home mechanics use one to get the right magnitude of torque rather than going for a precision engineered torque of 5Nm+/- 0.01. Basically we want stuff to be tight enough but not too tight and for most bike parts that’s a pretty big range – it’s always tempting to give stuff an extra nip when doing it by hand and the torque wrench is just a way of saying “no, that’s fine, step away from the bolt now otherwise your future may hold an afternoon of drills, dremels, swearing and spending”
Exactly, and let's face it - most printed torques on parts are whole numbers which indicates they're a bit of a finger in the air too.
Actually haven't checked mine for ages- haven't had any really precision stuff to do since the last cylinder head... But even though it's pretty old and I often forget to zero it, it still tests out fine every time i do check it.
Now the big cheapy, that'd be funny at this point- I basically just use it as a massive ratchet and it cost £8 about 20 years ago...
