Torque wrench accurate?

[rmanrman]

I have a mechanical craftsman 1/2 torque wrench about 12 years old purchased new. I’m primarily using this wrench for final lug nut tightening usually at 85lbs. But what I’m not doing is setting the torque to 0 zero after each use. Is this affecting its accuracy? Would it help to set it at zero for a week to allow the tension spring to reset? It’s the type that clicks when torque is reached. Have not lost a wheel on my vehicle. Thanks

 

[Neggy]

https://www.norbar.com/Portals/0/Wind%20Torque%20Wrench%20Back%20Blog.pdf

 

[FredWanaker]

send it to http://teamtorque.com Outstanding service and speed. Comes back with a calibration letter as well.

 

[duneslider]

It probably isn't accurate anymore but I am sure it is just fine for putting lug nuts on a standard automobile. You may not want to be torquing expensive aluminum heads with it.

I craftsman that is pretty old that I got from my wife's grandpa's garage when he passed, I compared it to my beam torque wrench and it was close, within 5 or 6 lbs of each other. Certainly good enough for lug nuts.

 

[K'ledgeBldr]

Or just buy your own tester/analyzer-

https://www.mountztorque.com/Validator-Torque-Wrench-Tester_2

Not inexpensive!

 

[ycgoat]

I just posted on another post just like this. I almost broke some bolts using my HF torque wrench, fortunately I knew it felt wrong and ran out and bought a cheap beam type.

 

[FredWanaker]

I think $49 they take it apart, clean and check it, then send a calibration letter showing what it actually is. That includes the return shipping.

 

[02camaro86]

its definitely off. you should never store a torque wrench with any load on it. always set it to zero. but as mentioned its probably fine for lug nuts. then again ive never broken a stud or lost and wheel and have never used a torque wrench on lugs, but thats another argument for a different thread.

 

[gagecalman]

I worked in several calibration labs for about 35 years. I repaired and calibrated all types of mechanical test equipment like micrometers, calipers, indicators as well as torque wrenches.

I think $49 they take it apart, clean and check it, then send a calibration letter showing what it actually is. That includes the return shipping.

According to their price list that's just for calibration.
Min adjustment charge is $44.
Hourly labor (repair) charge is $75.
Unless it's a nice wrench it's probably not worth sending out.

its definitely off. you should never store a torque wrench with any load on it. always set it to zero. but as mentioned its probably fine for lug nuts. then again ive never broken a stud or lost and wheel and have never used a torque wrench on lugs, but thats another argument for a different thread.

When you store your micrometer click type wrench set it at the lowest setting. This will keep a small amount of pressure on the components inside. Do not back it all the way out until it stops turning or zero. I used to get a lot of wrenches that would still click but would fail calibration because the handle is backed out until it stops and the break mechanism gets misaligned if the wrench is bumped.

Some additional info:
I saw a lot of very low-quality wrenches sent in for calibration. Unfortunately, they are not very reliable and are too cheap to repair but are probably ok for the occasional user.
In certain applications torque is important so here are a few tips to keep in mind:

• If you have a critical torque application a dial wrench usually works best.
• Most click type wrenches have grease inside to lubricate the breaking mechanism so you should exercise the wrench several times by applying torque at the highest possible setting prior to use.
• Most click type wrenches are only accurate from 20%-100% full scale.
• Some torque wrenches don't have a pronounced break and it’s very easy to pull past the break and over torque. Try to stop your pull as soon as the wrench breaks.

I am sorry this is so long but you can have the best wrench but still wind up with inaccurate results.

Jim

 

[PoorUB]

I have a couple clicker type torque wrenches. they are both from the 80's.

I have never calibrated either of them, but if I get a square socket, and put one against the other they are within a few foot pounds of each other. Last check I think it was 3 foot pounds. So either they are pretty close, or they are both off!

 

[infinkc]

Wonder if something like this can be used, put one end in like a vice, set it for say 100ftlbs. Connect your torque wrench that’s set to 85 and watch the reading when it clicks.

 

[Hawke]

Unless your torque wrench is calibrated at least every year, all you have is a more expensive wrench that goes click.

There are a range of electronic devices on eBay that are OK to confirm the accuracy of your wrench. They are certinally better than nothing.

 

[RPH]

Where I worked prior to retiring we used lots of electronic test equipment at the expensive end. After going ISO needed to track all instruments from torque wrenches to high end scopes. The high end equipment would be replaced every 5 years, fluke meters every two years, torque wrenches if the needed calibration were replaced with new, same for measuring. We did check against standards but the recalibration costs on some items was more than replacement. They would charge $100-200 to calibrate high end flukes. For the $300-400 a new meter costs it was more effective.
Teckton torque wrenches are cheap and very functional.

 

[cannuck]

I hate to have to sound like a broken record...but: The range of tolerance for almost any torque wrench fall WELL inside the range of variation in bolt tension for typical thread conditions. This is why many critical components are now attached with TTY (Torque To Yield) fasteners. IF you actually have a critical application, buy a top quality beam wrench (dial type or some kind of trigger such as my old Repco aviation stuff) and don't lose any sleep over the torque value or wrench calibration. If you want to be far more accurate in tightening: learn about thread, washer, geometry etc. characteristics related to fasteners.

 

[Renegade1LI]

A good way to tell if your wrench is worth calibration, did it come with a calibration certificate? If it did it’s probably worth it, the work we do i have to get them calibrated every year per spec requirement.

 

[Snapped-off]

Most click type wrenches have grease inside to lubricate the breaking mechanism so you should exercise the wrench several times by applying torque at the highest possible setting prior to use.

We're trained to exercise them 6 times at 60%. Probably doesn't really matter as long as they get worked.

 

[428PI]

Put torque wrench on say 75 lbs and put a 75 lb weight at 1 ft from the socket and put it on a wheel lug and see if the wrench clicks with the weight? Of course you would have to make sure the 75 lbs is actually that weight. I always backed off my click style wrenches and only had one calibrated once in my 40 years as a mechanic. It was a dial type 3/8 torque wrench that the dial would move when torqueing a nut when the nut would "jump" a little.

 

[FredWanaker]

if someone is too cheap to send it out I would suggest coupling it to a beam style torque wrench and comparing the two. You can slide a shallow socket on so both wrenches can couple together thru it. Beam wrenches don't change unless they are bent, welded on, broken, or the laws of physics change.

 

[SILVERPLATE]

I have some mid seventies Snap On click units, are they worth having checked.