Question about torquing fuel line B-nuts by feel for 6 years
Ngl I spent years snugging fuel line B-nuts with a short wrench and calling it good, mostly because that is what the old guy in our hangar at KAPA showed me back in 2018. Last Tuesday I was doing a fuel line on a 172 and the A&P next to me handed me a crow's foot and a dial torque wrench and said my "feel" was marking up the hex flats on every nut I touched. Sure enough, we checked a few fittings I had done and the flats were chewed and a couple were at maybe 60 inch pounds when they wanted 90. I felt like a total rookie. Anyone got a cheat sheet or a go to torque setup for tight B-nut spots, or do you just keep it in your head after a while?
Wait, the crow's foot is actually the problem here, not your feel. Using one throws off the torque reading since it changes the lever arm, so if you're just clicking it on at 90 you're likely under torquing. The old guy's feel method wasn't wrong, you just need the right adapter or a torque wrench that reads true in tight spots.