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Screws Shaking Loose

  1. Apr 22, 2012 #1
    Can anyone explain how vibrations actually shake a screw loose from a shelf? What is happening there?
  2. jcsd
  3. Apr 22, 2012 #2
    My suggestion !!!....screws are essentially 2 inclined planes wanting to slide past each other. It is only friction that prevents this happening. If there were no friction screws would have a tendency to unwind under any load at all.
    I would imagine that constant vibration enables slippage to occur and this is bound to result in screws getting slacker. I have never come across vibration making screws tighten up !!!
  4. Apr 22, 2012 #3
    Expansion and contraction

    as the sound waves pass through the object in question it expands and contracts this action is whats turning your screw

    Wood expands screw loosens up some
    Then then wood contracts but the screw is in a slightly diffrent place so it becomes a question of least resistance is it easier to sheer metal into wood or turn the screw?

    I could be wrong but thats my take on it
  5. Apr 22, 2012 #4
    Thank you.
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