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Hot take: I think the torque value books are wrong sometimes
I was torquing a main landing gear axle nut on a 737-800 in Atlanta last Friday and the book said 90 ft-lbs. But the old nut came off way easier than that, like someone had torqued it to maybe 60. I went with my gut and put it at 75 instead after checking the threads were clean. Anybody else ever just trust the feel over the manual on something like this?
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jennifer9652mo ago
Did you see that article in Aircraft Maintenance News a few months back about torque variance on humid days? They tested a bunch of bolts and found the lube and even the temperature can throw off book values by 10-15%. So yeah, sometimes the feel is the only thing you got, especially with older gear that's been through a few cycles.
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spencerm462mo ago
Hold on, pretty sure humidity actually makes torque readings go up, not down, because the moisture changes the friction. That article might have meant the actual clamping force was off by that much, not the torque wrench reading.
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kimreed1mo ago
Come on guys, the book values are there for a reason, and they're tested under controlled conditions that account for all those variables. Going with "feel" on a main landing gear axle nut is asking for trouble down the line, especially on a 737. Humidity and temp might change things a bit, but that's why you clean the threads and use the right lube like the manual says. If the old nut came off at 60, it was probably under-torqued by the last guy, not a sign the book is wrong.
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