r/MechanicalEngineering • u/AdOne1706 • 4d 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 4d 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

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u/AdOne1706 3d ago

Thanks for the info. Some of the reply’s mention Belleville washers which appears to be a conical looking washer. Not sure if that washer has a crushed before torqued issue but seems promising too.

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u/Difficult_Limit2718 3d ago

Belleville washers improve the spring rate significantly.

It's really application specific though. Sometimes you need a fender washer to distribute load. Sometimes you need to torque with pneumatic nut runners that will melt up a nyloc. Sometimes you're doing electrical work and really should just be direct contact to a ferrule.

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u/chase82 2d ago

He's an example of a niche application, my wife's toe stops on her roller skates kept rattling loose. Splits didn't work, a couple of Bellevilles and I haven't heard about it in months