Vibrating a fastener loose - GIF

[Jon]

Vibrating a fastener loose.




Previously:

D shackle nut vibrates off of bolt - video
Vibratory feeder bowl - GIF
Demonstration of concrete vibration - GIF
Truck cab vibration testing system - GIF
Vibratory pile driving hammer - GIF

[Gadgeteer]

An excellent demonstration to show why safety wire is used on airframes. Learned to use the spinning wire pliers in the AF, many decades ago.

[hemmjo]

Make me wonder, if that little motor was turning the other way, would the nut move down the bolt?

[Frank S]

Make me wonder, if that little motor was turning the other way, would the nut move down the bolt?

To complete your question or if the bolt would have been a left-hand thread. The answer to that would be no. vibrations are a waveform much the same as a radio frequency appears on an oscilloscope. it is at precisely when the vibration wave is at a 90° to the pitch that loosening can occur but only during critical frequency resonance, this can happen either on the upcycle or the down cycle of the wave.so so a rotational vibratory means of creating vibrations will not alter the cause and effect due to its rotational direction. All it is is a means of creating the wave Fasteners made with duel or compound angles are slightly less prone to the effects of vibrations IE a thread pitch with say as 60 and a 45 or 30°cut angle. this makes them expensive, but at the same time can reduce the torque value for them to be tightened, which can reduce their clamping strength. One way to counter that is to cause an interference cut angle between the internal and the external threads the ductility of either component is forced to deform to the other. fasteners such as these are often one time use and next to impossible to remove or to tighten further due to loosening from stretch or embedding into the materials being held together. Even fasteners secured with lock wire are not the perfect holding solution, long term exposure to vibrations will eventually cause metal fatigue in either the fastener or the members being held together, making it all the more important for things especially aircraft to the regularly inspected. and even having certain components disassembled and re assembled at times.
Left hand threads are effective only on things that rotate in a certain direction such as the circular saws the wheels on the left side of trucks are a couple examples

[Elizabeth Greene]

>> Even fasteners secured with lock wire are not the perfect holding solution

Can confirm. The valve retainer on pulsejets is resistant to any kind of anti vibration solution.

[jrouche]

Southwest Airlines no doubt JR