I did a search on this, but the last thread I found was over 10 years old.

I have two clicker torque wrenches that are at least 10-15 years old, both Craftsman so they're decent quality. I'd like to have them checked for accuracy, and recalibrated if necessary. Do any local shops do something like this as a service, such as Napa, AutoZone, etc? Are there other options that won't break the bank?

 

I would like to know as well.

 

Short answer is the wrenches have served a good life. Over 10 years someone has not relieved the spring tension. Clickers are notoriously inaccurate. If you don't want to spend money on a good (read accurate) load cell based digital wrench (~$200-250) then go get a new Craftsman. Cost ~60 each for a 1/2" & 3/8" set. They are good out of the box. Just make sure to spin them down to NO tension after EVERY use.

Utah

 

As a follow up, I always loosen them after use, though I'm sure I forgot a handful of times over the years.

Do the load cell based units stay accurate "forever"?

 

parts stores don't do this at lest not by me. but a good mechanic's tool store should. it would be the same place that rebuilds IR air tools. but idk if recalibrating a carftman torque wrench is even possible. if you no longer trust it I would compare it to a buddies or just get a new one. the digital ones are very nice.

 

Learn something new everyday. Spring steel (in some uses I am familiar with) can be extremely durable even over long periods of time. I have not backed off on my settings for my wrenches in storage. Of course a good way to check them is to somehow mark or measure a known torque and compare it to the test wrench.

These selections came from a white paper on the subject:

It is accepted that torque wrenches should be serviced in line with manufacturers recommendations or no longer than 100,000 cycles, or when a visual inspection reveals old or dry grease, parts that show signs of excessive wear, loose or unstable components.

Most click wrenches are built with an internal spring mechanism that is compressed to against a lever. Adjustable wrenches use springs that must meet a linear capability test. After use, externally adjustable click wrenches should be turned back to minimum scale value. This helps to preserve the linearity of the spring and calibration of the wrench. All calibrated wrenches should be backed off to the minimum setting when stored. Calibrated wrenches use a spring with a known linear range. It is thought (and has been proven) that leaving a calibrated wrench at one setting impacts spring linearity, disallowing accurate use at other settings. It does not happen every time, but over time linearity can be impacted causing error. This is the reason for the recommendation to turn a wrench back to its minimum setting when not in use. If you use the wrench at only one setting, you might consider a "preset" version that is set at one setting. This has no scale and is set by a torque analyzer. It requires no adjustment to minimum and can stay set at one torque setting without issue to linearity.


Accuracy can be stated in terms of Full Scale (FS) or Indicated Value (IV). There is a big difference in result as FS accuracy indicates the allowable error over the full-scale range of the tool. IV accuracy indicates allowable error at the set point on the wrench. IV stated wrenches are more accurate, especially on the lower end of the range. It is important to determine if the accuracy needed for an application can be obtained with the torque wrench selected.

I have tried a bunch of ways to put the the value chart here but when I submit, it jumbles the numbers. I even tried it manually but it does not work.

Source: Mountz Torque

 

By chance I came across a post on a garage forum that mentioned a tool testing service that happens to be nearby. I just submitted a request for quote, but the forum member said they were $28/wrench, which is half or less than what I've seen elsewhere. I'll report back once I hear from them, as the post was a couple years old.

 

You can always buy a torque block/gauge and do the calibrations yourself. On the Submarine we had both dial indicating and digital torque blocks to calibrate our wrenches. Don't want an almost 3700 pound Mk48 ADCAP torpedo coming loose from its straps due to improper torque, lol.

 

Here's a fun site that will show you multiple styles of torque blocks/transducers available. They aren't cheap, but can essentially be used forever.

http://www.norbar.com/en-us/Products...gory_multid/78

 

Well that didn't pan out as I expected. $55/wrench. At half the price of a new one, and considering how old they are, I may as well just buy new wrenches. doh!

I think I'll just do the dead weight @ 1 ft from the head check and if they're still close, call it good enough