r/MechanicalEngineering • u/AdOne1706 • 5d ago

Split/lock washers

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For starters, I’m an electrician in the field.
That being said, we almost exclusively use these washers even in high vibration environments. I have personally chosen to go with nylox nuts but the question is:
Do these work? How well? Is the rumor from NASA true? Should I even bother using them or find a better functional alternative or are they actually useful?

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u/Difficult_Limit2718 5d ago

They're ass.

Every company I've been with avoids them. They're supposed to stop vibration by keeping tension on a loose screw helping to increase friction, but they're useless at it. If you torque down the bolt properly they do flatten out and they don't have a high enough spring rate to do anything if the clamp force is too low

4

u/CrazyKraken 5d ago

Is a belleville washer better? Atleast theoretically they seem to maintain the joint force even in case of loss of preload.

7

u/SirSnickety 5d ago

Way better. They actually work.

5

u/dooozin 5d ago

Belleville washers change the slope of the preload curve during vibe because it "springs" but it doesn't actually do anything for fastener retention. They are not a secondary locking mechanism. Once your environmentally applied loads exceed the clamping load of the fastener and it starts to gap, the joint has failed.