[Closed] Dropped torque wrench

Dropped mine more than twice on to concrete...its the Superstar one...I'm still alive and the bikes are still in one piece!

Do you know someone local with another torque wrench? I wonder if you could couple the drives together and see if they click at the same time?
I've never tried this mind, the thought just popped into my head.

what he said but use a nut and see if you click at the same torque setting

I'd not worry, yes they lose their calibration over time, but unless you actualy break it then it's unlikley to be out by more than a few percent.

I'm guessing it didn't even come with a calibration certificate in the first place?

Yeah my mate has one, I'll try that.

Otherwise, probably ok then?

you can check the calibration easily enough with some maths:

clamp the drive in a vice, so that the handle is horizontal.

hang a weight off the handle, calculate what torque this creates, see if the 'click' agrees.

try a few times, and with different weights, to check the full range of the scale.

it's not a perfect process, but it's better than not calibrating at all.

How do you know that the one you are calibrating against is calibrated?

"Dropped mine more than twice on to concrete...its the Superstar one...I'm still alive and the bikes are still in one piece!"

I assume you just use the torque wrench for show? ..... Its not really doing you any good.

Bottom line is a torque wrench is not a tool, it is a precision measuring instrument. If it has been dropped it needs to be checked. Up to you if you do, or course, but without calibration you may as well not use it.

I was in the Facom torque wrench calibration lab last week, they test the testers using pretty much the technique awhiles states, with a bit more control and documentation.

why not call machine mart or similar and see if they do it?

The last torque wrenches I bought for work were about £45 each. The calibration cert was £36 each. They all clicked at different points on the same setting. I think I was ripped off with the calibration.

Waiting to hear back from a local place with a price

"The last torque wrenches I bought for work were about £45 each. The calibration cert was £36 each. They all clicked at different points on the same setting. I think I was ripped off with the calibration."

and this means what exactly ?

you mean the nut was in a different position ? also what was the % variance in the calibration report and what end of the scale were you using your wrench in. Ie an average 5-25 wrench will not be as accurate at 5ftlbs or 25ft lbs as it will at 15ftlbs

I assume you just use the torque wrench for show? ..... Its not really doing you any good.

Maybe if getting the correct torque is critical, but seeing as most bike parts don't even come with instructions as to whether the bolt should be greased or not, it's hardly critical.

The last stem I had with the torque printed on it stated 4-5Nm, that's a 25% margin! Knowing that your torque wrench is accurate +/-1% or even a really bad 10% isn't going to affect you. And then there's the fact that no one actualy calulates what the torque should be for a combination of parts. All very well knowing that the carbon steerer on specialized bikes is OK for 5Nm on the stem bolts, but what if your stem has m3 rather than m4 bolts, or has 3 or a 1 bolt clamp, what if the stack height of the stem is different? Unless you've sat down and done pages of calculations, had them checked by someone else who's been audited and certified by LRQA, you're just using [i]"the torque wrench for show"[/i].

I think I was ripped off with the calibration.

did you not get the cert? 😉

If I were concerned I would do as ahwhiles suggests and use a container of water for the weight to make it easy to change

Bottom line is a torque wrench is not a tool, it is a precision measuring instrument. If it has been dropped it needs to be checked. Up to you if you do, or course, but without calibration you may as well not use it.

He's using it for his bike not aircraft repairs.

at work, we calibrate a lot of our own kit (it's an aerospace certified lab, we're up to our neck in quality-control)

some of the torque wrenches we've seen are ab-so-lutely miles out. like 200% out. (and that's new kit, not stuff that's been knocking around the shop floor for 7 years)

that means torquing to 15Nm, when you want 5.

if it matters, it matters.

ok, out of curiosity I checked mine. Takes less than 5 mins

torque wrench with square 'bit' in vice. Set to 10Nm
5kg weight with two tie-wraps to hang it from. Move it up the handle to the point where the torque wrench 'clicks'. Distance = 17.5cm

So,
Force = 5kg x 9.8 = 49N
Torque = 49 x 0.175 = 8.5Nm

Not accurate but close enough to 10Nm for me and super easy to do.
Note that you need to use quite a large weight to swamp the effect of the weight of the handle of wrench itself.

Cost = 0
Time = 5 mins
Accuracy = good enough for bike work

I also note the my wrench says it always has to be zeroed after you use it but I forget half the time. I don't know if that screws it up but I would guess so 🙁

He's using it for his bike not aircraft repairs.

The application (no matter if it's used on a tractor or stealth bomber) doesn't change the fact a torque wrench is still a precision instrument.

If accuracy is not the goal, just use a ratchet handle, or accept it could be 200% out.

I also note the my wrench says it always has to be zeroed after you use it but I forget half the time. I don't know if that screws it up but I would guess so

Yes, it can do. The spring can take a permanent set and lead to errors.

I'll find someone with a vice and try that then.

Trailrat.

We've had a particular troublesome tooling part that requires torquing to 18Nm. I bought some 5-30 torque wrenches that had the proper attachment to torque the part up. We torqued up some parts and all seemed well. Then it was stripped later for maintenance and another shift did the work with a different torque wrench, same model, bought at the same time, calibration cert. The part became troublesome again, so checked the work and the torque wrenches and there ended up a half turn difference at the same setting between 4 torque wrenches. This is on a M10 fine pitch threaded cap with an 8mm AF "nut head". Not lubed. The lightest clicked at 14Nm the heaviest at 23Nm, both set at 18Nm.

I will have to dig the test certs out and get them redone somewhere else.

If it's out, can I recalibrate I myself, or is that not a DIY job

I'll find someone with a vice and try that then.

Also worth noting, consistency is probably more important than accuracy, so check a pair of bolts to ensure they are the same and one won't come loose (stem to steerer, faceplate, crank pinch bolts etc).

Spanner it is then

My local garage supply place checks then for free against a calibrated test rig. Look for a place that fits ramps, compressors etc and is ideally a service centre for one of the tool companies - like Sealey, Britool or CP etc.

Hth
Marko

5kg weight with two tie-wraps to hang it from. Move it up the handle to the point where the torque wrench 'clicks'. Distance = 17.5cm

So,
Force = 5kg x 9.8 = 49N
Torque = 49 x 0.175 = 8.5Nm

You forgot to take the self weight of the wrench into account.

sorry you lost me tinas when you started trying to tell me a tube has a torque limit.

same with handlebars with torque limits - its bullshit and you know that.

it has a limit on clamping force - that doesnt equal a torque.

its an arbitary number.

case in point my ritchey WCS carbon. seat post has a limit of 4nm. if you can get that seat post to keep your seat in place at 4nm your a clever man .... cause it wont happen with all the magic paste in the world- and im not the first to find that

Its about guidance and not being stupid. even with a torque wrench ive watched folk apply silly torques to things "but the wrench hasnt clicked yet" ..... did it ever occur to you it might be broken ?

How ever - suggesting that hitting it off the floor makes no odds.... thats just stupid.

BBS

"so checked the work and the torque wrenches and there ended up a half turn difference at the same setting between 4 torque wrenches. This is on a M10 fine pitch threaded cap with an 8mm AF "nut head". Not lubed. The lightest clicked at 14Nm the heaviest at 23Nm, both set at 18Nm."

how did you check this ? - im stumped as to how you could check without having a torque wrench calibration device.

andyr- You forgot to take the self weight of the wrench into account.

Note that you need to use quite a large weight to swamp the effect of the weight of the handle of wrench itself.

In my case this meant using a 5kg weight which was 20x heavier that the wrench itself and as the cog is somewhere in the middle I estimated the effect to only add 0.15Nm so I didn't care too much in the overall picture

I'll calibrate it for cake - I manage 13 UKAS laboratories so know what I'm doing.

Most of the time.

Where are you?

andyr - Member
5kg weight with two tie-wraps to hang it from. Move it up the handle to the point where the torque wrench 'clicks'. Distance = 17.5cm
So,
Force = 5kg x 9.8 = 49N
Torque = 49 x 0.175 = 8.5Nm

You forgot to take the self weight of the wrench into account.

And Cosine error.

And Cosine error.

Based in the Midlands at the moment as I've just opened another laboratory near the airport.

I'll happily send cake if that's a genuine offer to do it?

It is a genuine offer - done a few bits and pieces on here for people. Where are you?

North Scotland 🙂

I can post it and send money for return postage. There's nowhere local to me that can do it without sending it elsewhere.

Ha! My email is in my profile. drop me a line and I'll forward you my address. I'm not fussed about return postage.

Just cake, only cake.

I'll send it back with a certificate - not UKAS certified as they have to go through the system and it raises too many questions. It will be calibrated in exactly the same way though.

Ah, lovely outcome 🙂

Not yet, not seen any cake.

Don't drop it when you open it up on it's return.

I'll drop you an email, thanks very much.
Drac, no danger!

I dunno you've even dropped your email.

Don't drop when you open it up on it's return.

I'm sure the PF delivery people will have handled it with reverence - no chance of them slinging it in the van.

I'm curious though, what mechanism is it that makes a TR (which consists of a spring and other fixed mechanical bits) go out of calibration if you drop it? I can't see anything obvious which is likely to adjust when doing that.

I own a couple which have never been calibrated - will try the ghetto calibration method suggested above and see how they are (would be interesting if a few of us can report back).

The type 2 tools - setting type are a little hardier than the type one type which have a indicating dial on them. On pretty much every site I visit, torque tools are calibrated every three months 😯 Most sites expect the user to check them before they use them.

Replied to your email Chris.

I've mentioned this on one or two threads before, sorry for being boring; set the torque wrench, do three practice "clicks" on a spare fastener mounted in a vice, then do the real thing

Reminds me, I really should bring mine into work to check it...

Can't imagine those China brand torque wrenches are ever calibrated in the first place

What does that mean about these types that get delivered with bikes?

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I got one of those Superstar PSA ones and it came with a genuine looking calibration certificate..

sorry you lost me tinas when you started trying to tell me a tube has a torque limit.

same with handlebars with torque limits - its bullshit and you know that.

it has a limit on clamping force - that doesnt equal a torque.

its an arbitary number.

That was actualy exactly my point. Unless you've sat down and done a load of maths, tightening your stem to the correct torque for the bolts it fairly pointless, you'll crush the bars first.

Same with a front mech clamp, if you torqued it upto 75% of the breaking strain of the bolt (or more likley, the alloy clamp on a higher end mech), you'd probably crush the seatube, ditto the carbon handlebars, steerer. The recomended torque printed on them makes a whole host of assumptions, unless you know what they were, does it really matter how accurate your torque wrench is? It's probably not the least accurate part of the procedure!

A massive thumbs up for Lee who has checked it for me and returned it with a nice certificate showing the scale values against the true values. Thanks.

So, was it out of calibration/ has he adjusted it for you??

and did you send him cake?