Damned torque wrench

Sep 12, 2004 32 Replies

Hi



A little off-topic, but related to me about to attempt changing me rear-shocks...



I've now bought my 3rd torque wrench - previous ones bought from Argos, this one bought from a reputable equipment / tool specialist.



I have the same problem with this "trustworthy" calibrated TW as experienced, and rejected from the Argos crap. Difference is, I bought this from some distance away and is rather more difficult to return.



Now, the problem is, I just don't understand how the TW is supposed to work (doh!), I set it for, say, 10lb/ft (lowest setting), find a convenient bolt somewhere in the engine bay, and slowly apply increasing force to it - at no time is there the remotest click (apart from the return-ratchet), until I give up (having applied a fair bit of force).



Now, the first 2 I sort of gave up on as a bad-job, but I cannot believe all three were goosed. Is there something mind-blowingly obvious that you need to do with these things?



Exasperated



Mike.


Failing that, anyone know how many white-knuckles for 20N/m and 100N/m, respectively?

My guess is you're doing something horribly wong. Even the cheapest, crappest torque wrenches work; they just have terrible precision and accuracy.

Can you describe the type of wrench you have, and how you are stting it?

At 10 lb/ft you'll only hear the tiniest click, try 30 lb/ft & a wheel bolt. Also you need to press on the centre of the handle (unless you've splashed out for a Britool or a Gedore) to get the right torque.

Exact model -

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Navigate "Laser Catalogue" (left, bottom), "Bar - Ratchet - Socket - Socket Accessories - Socket Set - Torque" (Red) - select "Torque" "1/2D" Part No. 0316

To set it - there's a black knurled nut at the base, rotate 1/2 turn CCW releases the grip, rotate this so that the vernier "0" aligns" with the "10" against the "Foot Pounds" markings - setting closest to the bottom of the wrench, then tighten knurled nut back, 1/2 CW.

Cal label gives 21ft/lb at the 20ft/lb setting, 80ft/lb at 80fl/lb setting and 151ft/lb at 150ft/lb setting - so *should* have left the factory working and in cal.

Can't figure this damned thing out.

Kind regards

Mike.

to hear a click @ 10lb/ft you need to be investing in a torque wench that doesn't go much above the 70 or 80ft/lb mark to expect a little click when you are already using one that goes possibly in excess of 150ft/lbs is a little extreme I've got a 500ft/lb wench that only starts it's calibration @ 100ft/lb

Mike Dodd was seen penning the following ode to ... whatever:

None. 20M/n is nearly a two-finger jobbie, abd I'm not built like Arnold.

A few, but still less than you think.

That torque wrench doesn't click off as such. You just feel it give slightly. I used one briefly, but not through choice. Personally I prefer my Norbar wrench, that's far easier to set, and actually clicks.

moray

It really goes as low as 10lb.ft? You can do that sort of setting by using a box spanner without the tommy bar...

Go to something more sensible. Say 30 ft.lb. You shouldn't find anything of reasonable size easily that is less than that. You should feel a definite click.

Mike,

Reading your first post I was thinking "I wonder if it's a Laser like mine". Yup - same model.

The first time I used it was on a 20ftlb suspension top strut. I was just starting to get uneasy about the amount force I was applying when I realised the thread had stripped.

Having used it a bit more, I've got used to it. At less than around 20 to

30ftlbs the click is really quiet, and to be honest I wouldn't trust it at anything less than 30ftlbs.

Also, I don't know about your certificate, but mine was unsigned which, as a calibration certificate, makes it worthless.

Not a wrench I'd recommend...

10 - 150 ft lbs is a hell of a range for a quality torquewrench. I'd be surprised if it's really accurate at the lowest setting. My Norbar is a 20-110 ft lb model which covers nearly everything I need. It's 25 years old and as good now as the day I bought it (looks and feel wise anyway) as far as I can tell although I've never actually calibrated it. It will wind further back off the scale than 20 ft lbs and you can feel less resistance there so I guess it bottoms out at maybe 15. I've just tried it wound hard back to the stop like that and it gives a click you can hear 20 yards away and a good inch of movement at the end of the handle as it "gives". No less loud than the click higher up the scale and no way of mistaking it's reached the preset. Try yours at 50 ft lbs, put a 19mm socket on it and have a go on a car wheel nut. If it still doesn't click then it's crap.

Torque settings are not that critical though. Thread condition and the amount of lubrication you put on the threads affects them far more than any normal error in the wrench. A dry thread that takes 50 ft lbs to reach the correct clamping load might only need 35 ft lbs with moly grease on it. Most of the torque applied (up to 85% of it) only gets lost in thread friction at the best of times. The quoted torque setting is at best a rough guide for that particular thread in "average" condition. About the most the designer can do is specify dry or oiled but he has no way of knowing what type of oil or grease might get used, how much of it, how much rust, crap, burrs and other damage is on the thread after years in service.

Critical fasteners are tightened until they stretch a given amount or until a specific clamping load is reached.

I prefer my nearly 20 year old Norbar wrench too ;) Have a Britool one as well that's ok, but do prefer the Norbar.

Lee

The message from snipped-for-privacy@aol.comNoEmails (Dave Baker) contains these words:

And "Years in service" is what you need to get a feel for what's a reasonable torque for most applications. I use a torque wrench for things like sylinder head bolts, but the rest of the time I just use experience. I ain't broken anything or had anything come undone for years.

I've got all three Norbars. Dunno if they still make them all.

I have an 'Argos' torque wrench, bought at least ten years ago and it works perfectly. I can't guarantee the accuracy, of course, but it will be more accurate than using none at all!! I hear a clear click every time I use it when tightening wheel bolts etc.

Kev

You should fully back it off when not in use. Stops the spring taking a set.

-- Peter Hill Spamtrap reply domain as per NNTP-Posting-Host in header Can of worms - what every fisherman wants. Can of worms - what every PC owner gets!

IIRC, the Norbar says not to go off the scale. Could be it unscrews completely and loses its calibration if you go lower.

I leave it at the minimum marked setting of 20 ft lbs when not in use. Well, except when I forget.

Grrr, see my latest posting (hmmm, what should I call it, something like "Seized Bolts")

|Hi Dave

Blimey!, that must put you in your 90's then, one of our senior members perhaps??

8~)

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