I'm rather intrigued by these washers:
What are they called?
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Sign up to join this communityIt's a serrated lock washer. I've seen them used for two purposes:
Or, of course, a combination of the two. They are mildly effective against vibrations, and properly torqued very effective to ensure an electrical connection.
They're anti-vibration locking washers, the teeth digging into both the nut and whatever it's holding. They are also available with the teeth on the inside (as the pic), rather than as shown above, the outside.
They are spring locking washers.
They are designed such that the "teeth" oppose the nut vibrating loose.