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How to store Torque wrench

Chadwilliam1

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Is the properer way to store a click style torque wrench on the lowest setting? I have 2 Koblat torqure wrenches and I now have 2 CDI torque wrenches. The Kobalts said to stroew on the lowest setting but the CDI wrenches said nothing about it and both were delivered slightly above the lowest setting. One with a range of 5-75'#s and was at 10 and the other with a range of of 30=250"#s was at 40"#s. So what is the correct setting to dial these to when I am done?

thanks Chad
 
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2oolhound

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All the way down, that way the spring has no load so all the time it's stored it's not under tension and being fatigued.
 

dclassical

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My SK torque wrenches say to store them on the lowest setting, but I have seen others where the manual say all the way down.
 

rockchucker

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I turn them down all of the way until they stop then back in 1/8-1/4 turn. I also like to always have a Silica Desiccant package inside of the case or sitting right next to them at all times. This helps with moisture.
 

Charles (in GA)

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Most brands say to turn them down to the lowest setting. On some designs, turning it beyond the lowest setting will unscrew the handle and cause problems.

Long story short, don't turn it beyond the lowest setting.

There is no reason to turn it below the lowest setting. Indeed, some torque wrenches will have parts of the internal mechanism drop out of place and not want to go back together if you completely relieve the spring tension. Take it to the lowest setting.

Of course some, such as the split beam models from PI do not need to be set to the lowest setting, they can be left where they are, no springs to ruin.

Charles
 

PatDoody

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Def lowest setting. I have craftsman wrenches and keep them in the newer style blowmolded cases, you cant click them into the case unless the wrench is turned out.
 

6-Speed

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When I worked on cars the guys always gave me **** cause always kept my split beam set at around ~100
That's the nice thing about split beams ... you don't have to turn them down for storage. I just leave mine set to 80 lb-ft for lug nuts.
 

diesel research

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the spring thing is largely a myth.

steel or steel springs, do not fatigue/wear appreciably under moderate compression.

they fatigue/wear when rusted, abraded, heated, taken beyond limits, impacted, vibrated, or cycled ~10 million cycles. more wear or fatigue takes place during the adjustment process, as each one is counted as another cycle. the common coil can be thought of the same as a straight steel beam. the beam will fatigue from being flexed/bent too many times, but not from simply holding a static weight within its capacity range. steel doesnt fail from just sitting there holding some weight, unless the other above factors are introduced. axle or beam can sit under moderate load for 1,000yrs w/o fatiguing, provided it doesnt corrode.
 

diesel research

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They took a torque wrench and did not turn it down and tested it over a period of three months. They found it did become less accurate over the three months. Over 3 months, the HF torque wrench they used lost an average of 4.4 ft-lbs of accuracy when torquing to 70 ft-lbs. So, in this case, it was not a myth.

is that testament of the spring myth, or more testament of the harbor freight "quality"?

how did the relaxed hf model perform after 60 days?

notice how it became more repeatable after 60 days of sitting loaded?

looks like it needed a little break-in.
 
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amlv20

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Lowest setting, storing it higher or lower will eventually cause it to loose its accuracy.trust me. I used to always be told even back in high school never to leave them set high, so I kept all my torque wrenches as far down as the could go, then my 3/8 started to go off.when I had it sent out the snappy man told me that all the way down is also a big no no.so all my torque wrenches stay at lowest settings
 

diesel research

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I would be interested in seeing any real evidence you can provide to back up your claims.

only claim i make as far as the article, is the fact it became more repeatable. there is absolutely no question of that fact, based on chart you provided.

now science types know, "correlation does not equal causation", and there is not enough evidence to come to a conclusion, since they didn't test a relieved one. without any solid direct evidence backing up his/your claim, it does leave the question. is this a matter of "spring relaxation" or "tool breaking in" or "substandard mfg/reliability over time" (in general)? which of those above possibilities most well coincide with the fact the tool became more repeatable?

i am going with option #2, which may have been influenced by things such as burrs or poor seating possibly related to #3.

the fact the shop has a well used but quality manufactured torque wrench that stays set at 550ft/lbs used daily, and passes cal every year (for atleast 5yrs in the hd truck tire lane), fairly well supports such hypothesis.
 
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diesel research

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the anecdotal is not part of the evidence. merely a side note that cancels out his anecdotal story (he never did publish a valid complete test with evidence, just as i did not)...

what is evident, is we have known metallurgical properties, an inconclusive/incomplete/invalid test, a questionable manufacturer, and test results such as increased repeatability, that do not coincide with his unproven theory (unless that is a property of so-called "softened/worn" springs?)

the wrench went from varying 2ft-lbs, to holding steady at less than .5ft-lbs of difference.
 

2oolhound

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Scanning the web the general consensus is the spring will weaken or as some sites phrase it "it has a memory and will have a tendency to return to the setting it was stored at". They all seem to agree to store it at the lowest setting in it's range, not slackened right off as I had said in my 1st post (sorry). Here's a video by Norbar the inventors of the torque wrench and who are worldwide selling to over 100 countries. Many of the popular torque wrenches in use are rebranded Norbar, suchas my 1990 cira Gedore. The video mentions storage at the end.

http://www.norbar.com/products/videos-on-how-to-use-torque-products/how-to-use-a-torque-wrench.aspx
 

TwoInch

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im with diesel.

i believe its largely a myth. when i first read that carcrafts write up i though "what a waste of time and paper." that "experiment" was nothing that would give results conclusive of anything at all. all it showed is that the HF torque wrench became more precise when left on a setting for two months.

springs are well understood, as is the steel used to make them. spring creep, spring set, and spring relaxation are real, and also well understood. you will lose a very small percentage right off the bat, but should lose very little after that. probably why the HF model lost a little bit, then became much more precise after a little "break in"

here is NORBARS reccomendation.

"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 adversely affect the calibration of the wrench"
 
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TwoInch

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what was your quote of my post, and your own response about then???

i would much prefer a torque wrench that hits 65lbs within 1 lb(64-66lbs) each time, rather than one that hits 69lbs within 4lbs(65-73lbs) each time. your damn right.

the carcraft thing is a joke. its nothing conclusive or scientific about it whatsoever.
 

diesel research

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want to see one that is accurate and repeatable? have it calibrated after the break-in process, or buy one that is machined well enough not to show signs of break-in drift. problem solved. :)

of course, its still very possible that the backed off unit would have drifted as far or farther in their specific test facility, given HFs contracted manufacturers stellar reputations for consistent manufacturing and products....
lol.gif
 

TwoInch

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Again, take a closer look at the results. It seems you don't understand them.

When it was hitting 65 ft-lbs, it was actually set at 70 ft-lbs. It became more precise as the accuracy became worse. Even at it's worst precision (When it was brand new) it was still quite precise and it was quite accurate.
:
i absolutely understand them. and yes i would choose the more precise, even if it was slightly more "off" than the other.

do some deep research into spring relaxation, set, creep, cyclic fatiguing and static load... come back after you do your research and make an informed statement.

that last statement on the carcraft thing where he says "If the wrench were left for longer, the actual torque would continue to drop." is an assumption. the spring will not continue to relax indefinitely. there are many torque wrenches left locked in a certain setting for very long periods of time, and hold calibration.

i dont leave mine in setting, and i dont advise people to with theirs. but i do believe that its hyped way out of proportion.
 
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P_I_Torque

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One key ingredient to most click type torque wrenches, micrometer adjustable style, is the rather large coil spring used to compress the release mechanism, requiring more or less force to break-over. I've attached a "see through" image from marketing for reference. We've done numerous tests where you have Wrench A go through 60,000 cycle calibration check, while Wrench B sits wound up to 75% of full scale with 0 cycles. Guess which ones falls out of calibration first over the same time period?

Micro.jpg

There is one exception however. If the springs are uniformly "broke-in" before they enter the torque wrench you can limit and reduce these effects dramatically, but not eliminate it. It's one of a few process we do here at Precision Instruments to lessen the effect should someone forget to turn down the torque wrench to the lowest setting, or require the tool to remain set for a long duration of time (preset models for example).

Grab the latest copy of the Machinery's Handbook for the science behind a coil springs behavior. Many factors play a key role in operation and performance of a coil spring like those found in click type torque wrenches.

I would not base too much theory though on data received from one torque wrench test. If that one became more repeatable, it doesn't conclude 10 more will act the same. We retain months and months of data from our torque wrench cycle machines running two torque wrenches continually 365 days a year before any assumptions are made for product improvement. Ironically enough, two months ago we updated a process which improved our coil spring load memory by 40% at bottom scale, and 23% at full scale on most of our M line.

The article and test SK is referring to is accurate and similar to our in-house test data, speaking in generalities. I understand the point you are making TwoInch but it's all getting a bit off topic. With regards to how to store your torque wrench, follow the manufactures recommendation. Or yeah, or buy a Split-beam or Dial style :thumbup:
 
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rlitman

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what is evident, is we have known metallurgical properties

Yes, we do, and you are obviously not familiar with all of them.
There is more than just simple plastic and elastic deformation. Materials under stress over a long term will experience creep, and this is the property that causes issues. Creep is a big problem in plastics, and perhaps not a big problem in most use cases of steel, but this is one where it creeps up.

You should start by reading all of this:
http://www.mechrel.com/articles/Mechanical-Spring-Failure-Modes/
 

mkstuls

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How to store beam-type torque wrench?
or it does not need any care?
 

larryq

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