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Torque wrenches: calibrated every year or when it feels off? | Aircraft Mechanics - Free To Speak

Torque wrenches: calibrated every year or when it feels off?

I've been in the hangar at O'Hare for 12 years and I keep seeing guys skip the annual calibration on their personal torque wrenches. They say it's close enough until it clicks weird, but I had a 1/2 inch Snap-on read 12 ft-lbs low last spring on a flap track bolt, lucky I caught it before the final run. My argument is calibration is cheap insurance versus a rework or worse, but my buddy swears he's never had one drift that bad in 20 years. Who's actually checking theirs on a schedule, and have you ever caught a big miss before a job went sideways?

2 comments

2 Comments

the_terry1mo ago

And that's the thing, I read a piece in a trade mag a while back about how most torque wrench drift is actually from guys dropping them or using them to break loose bolts, not from age. The article said impact and abuse messes with the internal spring way faster than normal use ever will. So yeah, annual calibration is smart, but honestly it's only half the story. I've seen guys calibrate religiously and still miss because they leave it banging around in a drawer between jobs. My rule is check it yearly, but also if I ever accidentally drop it or use it for a cheater bar, it gets checked that week. That's how you catch a big miss before it turns into a real problem, not just waiting for the click to feel wrong. Have you ever torn one down and looked at the guts after a drop? It's eye opening.

emery2901mo ago

You ever actually crack one open after a drop, @the_terry? I mean, I get the abuse angle, most guys do treat them like hammers, but the real kicker is the beam style ones, not the clickers. A beam type can bend subtle and still read square on the dial, you'd never know until you check it against a test bar. The internal spring thing is true for click types, sure, but a friend of mine had a digital one drift 8 ft-lbs just from sitting in a hot truck cab all summer, no drops, no cheater bars. So yeah, yearly is the baseline, but the "when it feels off" crowd is playing roulette with a part that might cost 40 grand to replace.