Anyone used a digital torque adapter?

[Grim Reaper]

I have a few normal torque wrenches already but not sure if any of them are really in spec/calibration (certainly the two I inherited from my Father have never been recalibrated since they were bought)

Rather than sending them away to be calibrated I thought one of these could be useful, A to calibrate the wrenches I already have, and B use as it is instead of the wrenches if space precludes their use.

Just wonder if anyone else has one and can comment on their usefulness.

[2GBR]

Looks usefull, I have two Britool torque wrenches which i purchased 42 yrs ago when i had a Lotus twin cam escort and neither wrench has been back to Britool for calibration. I borrowed a mechanic friends nearly new Snap on digital mega bucks torque wrench when i put an engine together last year and my two wrenches were very very close like two ft lbs at 60 % and above within the range, and two to four ft lbs at 20 to 50 % of the range.

Biggest killer is leaving them set on a torque, and of course production work

[6speedmanual]

Interesting point, may have been discussed on here before:

How does leaving it "set on a torque" damage it?

 

Peter

[2GBR]

Most hobby/mid range and all budget torque wrenches have a coil spring within and leaving this under tension could possible lead to a need to calibrate or change the spring.

Just good practice to allways relieve the tension on the spring asap after each use

[LesG]

Leaving a conventional, mechanical torque wrench set on a torque, doesn't 'damage' it as such. Inside the wrench is basically a big spring, which, when left in tension, stretches over time. With the stretch comes inaccuracy. Best practice with these 'analogue' torque wrenches is to always leave it wound off fully before you put it back in your toolbox drawer.

The digital wrenches don't have the mechanical workings inside, and therefore you can just switch them off, or leave them to switch themselves off. They do also have more than one scale on them, lb/ft, nm, and in/lb, and an angle gauge aswell on the most up to date versions.

Regular calibrations are advised, otherwise you may aswell save your money, use your breaker bar and cross your fingers.

[Rob Walker]

I hang a known weight off mine at a measured 1ft from the centre of the drive to check accuracy with the drive held in the vice. Simples.

[ECR]

When I had my Britool wrenches recalibrated by the factory, the report showed varying divergence along the scale. So for instance they could be out by 2% at the lower end of the scale and 5% at the upper. A hanging weight is a good check but they really need to be checked through the whole range of use.

[tweeky]

Im with 2GBR always told/trainned to release the torque setting on a torque wrench

 

[Roger Ford]

How does leaving a spring under tension (is it tension? Or compression?) cause it to weaken?

 

I presume this is supposed to be via metal creep (slow plastic deformation even when the spring is well within it's elastic range), but I have my suspicions that this is more theoretical rather than practical.

 

Suppose I should check my torque wrench. I can't be bothered to reset it every time I use it, so it's been set at 55 ft lb for almost all of the last 10 years.

 

[tweeky]

Item 3.

[Roger Ford]

Reads

Always release the tension on the torque wrench to prevent “spring set” on adjustable or “clicker” type torque wrenches. This will ensure correct torque settings throughout the range of the tool."

Which doesn't explain anything other than giving it the name "spring set".

[2GBR]

I would have thought that any spring left under compression could have a need to be tested after a period of time. Good practice to test race car suspension springs every season or so, Ok to read the code for the poundage but what is the actuall. Also good practice to leave a race car on stands to let the suspension droop,Takes some tension of the springs and a little rebound of the dampers

[Mucus72]

Can't comment on calibration, but I purchased something similar last year to re-torque the rear hub nuts, by using this attached to a rather serious breaker bar. For me it was the cheapest/smartest way to get up to the force required.

[Mucus72]

In addition mine bleeps increasingly faster as you get closer to the torque number that you dial in. Which helps when you are hanging from the garage rafters and jumping on the breaker bar 😬

[Roger Ford]

Interestingly Norbar say the following:

 

Although considered by some to be good practice, extensive testing has clearly shown that unwinding a Norbar torque wrench to its minimum setting, hence relaxing the spring between uses, has no effect upon the wrench calibration.

 

However, if left for a long period of time without use, it is desirable to reduce the setting to the minimum scale value (often 20% of the maximum). The tool should never be adjusted to zero because this can adversel y affect the calibration of the wrench.

[CharlesElliott]

I've got one of these for the hub nuts....no spring 😬

[6speedmanual]

Hmm. Interesting range of opinions.

My view is that the spring inside is only working well within its elastic limit.

The wearing part it the click mechanism.

Norbar production wrenches using in car factories are basically similar to the home ones but the adjustent screw is lockable instead of being a knob. These are left set at a torque all their life. Small tweaks at calibration checks are, I always understood, to be for wear which changes the willingness of the mech to click.

The biggest caus of deviation in torque on most diy wrenches (norbar type) will be from parallax error when setting the chosen torque value.

 

Anyway for the basic low tech we are talking of, it's all a bit "indicative only" (except maybe some engine fixings). After all, do we use only clean, dry, new first use fixings with zero side load and no other friction on shaft during assembly? No. It seem common practice to slather much of it in copper grease.

 

Peter

[tweeky]

I think the ones Ive seen in car plants were called DCtooling and the measured the torque as the fixing it done up sort of like rundown torque then final torque stage.

 

 

Edited by - tweeky on 23 Feb 2014 12:26:13

[Grim Reaper]

Well, I've ordered one, it should arrive by Tuesday so I'll use it to calibrate my existing wrenches and report my findings back.

I have two Norbar twist end cap, (One small, one large) and a Lidl special large one I bought last year and which I leave set at 75Nm/55lbf for wheel nuts.

We'll see if any of them need tweaking to bring up to spec.

After this I will of course be offering torque wrench recalibration services for a modest charge.. 😬

[Roger Ford]

What I'd like is a torque limiting socket that I could use with my impact gun. Sadly they all seem to be 115 nm, which is about 85 ft lbs, so rather too high for our wheel nuts.

[Gregs79]

I've often wondered how accurate torque wrenches are from leaving the factory, but I have always loosed mine off inbetween use.

[wag]

Just because its digital does not mean it is accurate. Besides, variation between torque and shank tension in fastening (usually what you are trying to control) is huge

[LesG]

Roger; you can get torque-limiting bars for use with your impact gun. They look like a half-inch drive extension, with a fixed socket on the end. You order whatever torque bar you like, with corresponding socket on the end, and they work by 'locking up' when their torque value is reached, I.e., they won't twist/rotate/tighten anymore. It means you can buzz up your bolts quickly, and then final torque setting with your torque wrench. They are not for replacing your torque wrench though! Torque limiting is not torque setting!

Price? About £40 + vat each roughly.

[Grim Reaper]

Well the Digital Torque Adapter came this morning, and I have compared it with two of the three wrenches I have so far, the smaller Norbar was under performing (at an indicated 40Nm it clicked at 36 on the adapter) while the large Lidl £15 special was spot on (set to 75Nm it clicked at 75Nm +/- 1Nm on repeated tests)

Adjusted the Norbar to give a correct response via the allen key adjuster and it now clicks at indicated value +/-0.8Nm)