Years ago when I was a teenager, I stripped the threads on the oil pan plug of my '69 Ford. I didn't get the oversized plug to rethread squarely, and my car forever dripped oil for the remaining time I owned it.I have to say that it's fascinating to see the religiousness with which folks try to adhere to torque specs on fasteners. Thing is, ordinary fasteners could care less how much torque is applied. Enough to keep them from falling out, but not so much you pull the threads out of the material it's going into. In other words, they get tight. Since they are not squishing a gasket or a bearing or containing pressure, the correct torque is: "When they get tight enough, they are tight enough."
It's a plain old fastener, it's not doing anything special. I've always been amazed at the infatuation with torque specs for fasteners that just need to be tight enough not to fall out. You know when it's tight while you're twisting the wrench!
Do you need a torque spec for the screws holding a doorknob onto the door? The case screws on your PC? The hardware on your kitchen cabinets?
There'll be folks arguing with me, but seriously..... if you don't know it's tight while you're using the wrenches, then let someone else do the work.
Not to say I ignore torque values. When I split the case for my gearbox issues last fall, you can be sure i knew which bolt got how much torque and in what sequence as I put the bottom of the case back on. But for a plain fastener that holds a doodad onto another doodad, I couldn't care less what the torque spec is. It gets tight. A bigger bolt gets a bit tighter than a tiny one. End of concern.
Which means your torque wrench is calibrated and 20 ft/lb is within the middle 2/3 of the torque range of your wrench where it is most accurate? And, the threads are dry (no lube, no Locktite, no anti-seize, no liquid)? Both the bolt and the threads are clean? If the bolt/thread isn't clean it will wildly vary the true clamping force. Your torque wrench is a positive clicker that isn't influenced by the way you hold the wrench to the bolt -- the handle end is in the same plane as the bolt head? Being exact and all, you would be better off measuring clamping force and not bolt torque. And this being Friday where the Forum isn't always serious, I'm just busting your chops...I live in an exacting world. Therefore, I like to be exact.
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