Just found out that torque wrenches need calibration way more often than I thought

Ngl I was doing an engine mount swap on a 737 last week and my lead mechanic asked when I last calibrated my torque wrench. I said maybe a year ago. He pulled out a logbook and showed me that the factory spec says every 90 days or 2500 cycles. I checked mine on the test rig and it was off by 12 foot-pounds on a high torque setting. Has anyone else been skipping calibration this bad or was it just me?

3 comments

3 Comments

elizabethmason6d ago

Wait, @wade871, did your buddy end up scrapping that whole batch of bolts or just heat treat them again? I had a similar scare last year on a Cessna wing spar, caught the torque drift right before we torqued the final bolts because of a bad calibration cycle. That test rig sounds like a lifesaver, I bet the engineers would freak if they knew how close we came to snapping stuff mid-flight.

wade8716d ago

Bet that test rig saved some bolts from snapping mid-flight though.

simonp766d ago

That test rig is the real MVP. Saved a buddy of mine on a custom job last year, @wade871. We had a batch of bolts that kept snapping at 40% torque. Ran them through a simple rig with a load cell and found the heat treat was off. Would've been a total mess mid-flight.