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Is there a valid generic formula to roughly estimate a bolt's tightening torque similar to the "tighten by hand until seated, tighten XXX degrees more with your wrench"? I have used for many years the "tighten by hand until seated, then tighten another 180 degrees with wrench" on my gasket-type spark plug when new or "tighten by hand until seated, then tighten another 90 degrees with wrench" on retightening after inspection etc and the truth is that given the spark plug's position on my dirt bike it would be almost impossible to tighten it with a torque wrench.

So I was wondering if, given the materials included, the thread geometry (eg A2 M10x1.5 or 8.8steel Μ10x1.25 bolt to be screwed on aluminum triple clamp etc) and any washers/stoppers/gaskets included there would be a rough generic way to estimate the applied torque by tightening angle.

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I mean i guess there is. You cant always trust it though. my rangers caliper bracket bolts were "torqued to spec" but the one still came loose on my twice so i used threadlocker and then torqued to spec. I dont really think theres a generic torque spec. Not every bolt can be turned 180 degrees past tight. I say the best thing is threadlocker and just tighten it a little past tight.

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  • No, if you do that on driveshaft nuts they will definitely come loose and cause damage. So, use the correct torque values - engineers have put in a lot of work to quantify the conditions and applied loads for a reason. You may not follow their reasoning but bokts coming loose is most likely they were not clean or the torque meter not calibrated etc – Solar Mike May 5 at 20:00
  • Threadlocker? Most bolts from the factory on driveshafts have threadlocker on them....so id say its pretty fine. Secondly, i made sure the torque stick was calibrated, it was off by 1 ftlb. I looked up online and sure enough, plenty of people have issues with the ranger caliper bolts coming loose. – notbarnobi8585 May 6 at 13:33
  • Nuts are on the hub end... and many have licking washers with tags to bend or nuts with a collar to be punched. – Solar Mike May 6 at 13:53

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