I torqued the same cannon plug nut by feel for 3 years until a VOM reading made me look like a rookie | Avionics Technicians - Freelance Forum - The Community for Independent Professionals
I torqued the same cannon plug nut by feel for 3 years until a VOM reading made me look like a rookie
I always figured I had a good hand for cannon plug nuts, snug them down by feel and move on, never thought twice about it. Then back in April I was chasing an intermittent fuel quantity fault on a King Air in Tulsa and spent two whole days swapping gauges and chasing wires, and the actual problem was one connector shell I had "snugged" maybe two weeks before on a different squawk. My lead came over, put a torque wrench on it, and it broke loose at 8 inch pounds when the book calls for 25 to 30. I stood there holding the wrench feeling like an idiot because every intermittent gremlin I had blamed on pins or moisture over those 3 years could have been me and my wrist. Now I keep a small inch pound wrench in my box and check anything going into a pressure bulkhead or a high vibe area, which sounds obvious but half the guys on my crew still go by feel. We install hardware to a spec for a reason, and my hands are not a calibrated instrument no matter how many years I have behind them. Anybody else get humbled by a torque spec they had been ignoring, or am I the only one who needed a VOM and a bad gauge to learn it?
The part about "my hands are not a calibrated instrument" is dead on, but I gotta push back a little on the 8 inch pounds thing. A nut that breaks loose that low doesn't always mean it was never tight, because torque to break loose and torque to seat are two different numbers. Once a nut has been sitting and the threads take a set, or somebody used a little lube or never-seize, breakaway can read way low even if it was torqued right going on. So it's solid proof it was loose at that moment, but not really proof your wrist was off by 20 inch pounds for 3 years. What it does prove is the real point you're making, which is that a connector that reads loose when you check it was loose, and you'd never catch that by feel. A clicker wrench and a dab of torque seal is the cheap way to know instead of guess.