PSA: Your torque wrench might be lying to you if you store it wrong

I spent 10 years trusting my click-type torque wrench on every single job. Last month I brought it to a calibration shop on Elm Street and they told me it was reading 12% over spec. Turns out leaving it set at 80 ft-lbs in my tool drawer for months at a time kills the spring. The guy showed me the test bench results and I felt like an idiot. I talked to three other mechanics at the shop and two of them had the same issue with their own wrenches. Now I religiously dial mine back to zero after every use and store it in the padded case. Has anyone else actually had theirs tested or are we all just guessing?

2 comments

2 Comments

amy_murphy1528d ago

Different take on that lowest setting thing. If you set it to the bottom of the range without clicking through, the spring is still under tension. The real point is to relieve the spring pressure completely, which for click-type wrenches means backing it off past the click point until it feels loose. I tested this myself with a Harbor Freight model that came with a calibration cert - after three months stored at the lowest marked number it drifted 5% high. Storing it fully unwound kept it within 1% for six months straight.

mason.mary29d ago

Oh man, I gotta jump in here because you're mostly right but let me clarify one little thing. Dialing it back to zero is good but actually the real trick is to set it to the lowest number on the scale before storing it, not necessarily zero. My buddy who runs a calibration shop explained that if you crank it all the way down past the bottom of the range you can actually mess up the internal stop mechanism on some wrenches. He showed me a Snap-on that got wrecked because someone kept cranking it below its minimum. So yeah, store it at the lowest setting but don't force it past that point. Your padded case idea is solid though, that's exactly what I do now after learning the hard way too.