Tried a digital torque adapter on older hardware, surprising result

After 20 years of using beam wrenches, I finally broke down and got a digital adapter for a job on a DC-9 at the MRO in Tulsa last month. Calibrated it against our shop standard and it read fine, but when I torqued a 30-year-old fastener to spec, the bolt sheared clean off at 85% of the value. Turns out the old fastener had corrosion under the head that the fresh adapter couldn't feel, but my old beam wrench would have shown the drag. Has anyone else seen digital tools miss what analog ones catch on aging airframes?

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king.ruby26d ago

Never thought about it before, but that drag on the beam was doing the real work.