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I have a couple of already counterclockwisely tightened bolts and would like to know how much they're torqued to in the first place. I know they're torque to at least 25Nm but how much more I don't know.

I have a torque wrench (3/8" drive), and wonder if I could start with 25Nm and incrementally set (2Nm increment per step) and verify the torque by seeing when the bolt can be lossened by turning the torque wrench clockwise.

Does this method give a good enough approximation as decide by the size of each incremental step?

  • Hello, and welcome to Home Improvement. Why "counterclockwisely"? What is this for? What kind of torque wrench do you have? And, you should probably take our tour so you'll know how best to participate here. – Daniel Griscom Dec 27 '19 at 23:25
  • Those are called "left handed threads". – Harper - Reinstate Monica Dec 28 '19 at 0:22
  • I have a click type torque wrench (20-100nm) and it only torque clockwise (which I understand is the case for most click type torque wrenches out there). – skyork Dec 28 '19 at 0:27
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This is deceptively hard to test.

When torque is specified for a fastener, it's really the torque that should be applied when the fastener is installed.

Your test, which I believe is called a "first movement test" - creeping up on the torque until the fastener moves - tests how much torque it takes to make it tighter right now. You might naturally assume that it will first move when you first exceed the torque applied when it was installed. However that's not generally true for a number of reasons - the deformation of the parts upon installation, adhesion developing on the threads (corrosion or otherwise), the effect of static versus dynamic friction, etc. etc.

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  • Isn’t the OP loosening the fastener not tightening it as you suggest? – Solar Mike Dec 28 '19 at 23:08
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I would do the opposite, ie trying to tighten the bolt and finding the amount of torque to just make it move increasing the tightness.

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  • Thanks, but the torque wrench I have registers click only when it's turned clockwise. So for these bolts tightened counterclockwise I won't be able to tell the torque value – skyork Dec 28 '19 at 6:24
  • I have two click type torque wrenches and they both work either direction, one is Snap-On and the other I’m not sure. But “chinesium” or “cheap” stuff I would not trust for a valid reading anyway... – Solar Mike Dec 28 '19 at 8:03

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