Torque wrench

Somebody in my office is selling their used torque wrench. It is NAPA … for $25. How do i know that it is calibrated correctly? Is there a way to check it? He said that he only used 4-5 times and unless it is used lot for so long, torque wrench is usually still in calibration. Is he right? tx. much for the input.

If your friend never used the torque wrench as a breaker bar, never dropped it, and zero’d it out when finished with it, it’s a good deal!


Add to that never using it to loose a fastener.

It depends on the torque wrench. Some can be bought for that price new. Take a trip to the hardware store or NAPA and look at their torque wrenches to get an idea of what they normally sell for.

Torque wrenches are similar to tire pressure gauges in that you simply can not know how accurate they are unless you have them checked by a scientific instrument calibration service at a higher expense than what most people would be willing to pay. Anyone who pronounces their torque or tire pressure gauge accurate without checking it against a standard traceable to NIST is just guessing.

Beyond that, required torque values for vehicle fasteners are not normally critical so you should be OK as long as you don’t possibly damage a new torque wrench by dropping it or stressing it beyond its maximum rating.

For more critical applications such as in a scientific or research and development laboratory, airplane assembly and maintenance, NASA and the like, it is necessary to periodically check such tools for accuracy. A typical time between calibration checks is one year.

You can do a fair job of judging a measuring tool’s accuracy by comparing it to several others.

Assuming this is not a beam-type but a 1/2" clicker, a quick look shows NAPA gets about 80 bucks for a new one. I would say a lightly used one would easily be worth 25 dollars.

No torque wrench is dead-on and at some point they may require a calibration if they’re used normally. However, the cost of shipping it off for calibration may often be more than what the thing is worth.

Just my opinion here, but I don’t put a lot of faith into 1/2" torque wrenches when dealing with very low torque specs. (say 10-15 ft. lbs. etc.)
When you start dealing with figures that low then you should drop down to a 3/8 or 1/4 drive torque wrench.

I have a pretty old torque wrench that I lately wanted to check out.

I took my digital fish scale (have to trust that too, of course), measured 12" out on the wrench shaft, set the wrench and pulled (you just need a hefty & tight bolt to try it out on). The math is staightforward - X lbs. at 1 foot. I did it at several different settings. It’s not high tech engineering, but as far as I could tell it turned out to be pretty darned close.

Thanks much for reply.

i bidded $20 and i got it. i will pick it up on friday. i may want to play around and check with my fishing scale.

If your fishing scale is accurate within + - 2% measured against a standard traceable to NIST and labeled as such by a qualified instrument calibration service company then you are in like Flynn. Otherwise I would not let you with your torque wrench stand closer than 10 feet of my airplane if I had one.

Geez! The guy’s buying a used torque wrench. I never saw any mention of aircraft or nuclear reactors.