Don Terrill’s Speed-Talk

There was a link to a very in-depth fastener article in an S/T thread a year or so back. Among other eye-openers, the researchers discovered that a standard type lock washer had negative anti-loosening value...
If you ponder the not-uncommon 'lock washer over a flat washer' situation, it's clear that the best that could be expected would be for the flat washer rather than the bolt head to turn on the component...

MadBill wrote: ↑Sat Jun 23, 2018 9:51 pm If you ponder the not-uncommon 'lock washer over a flat washer' situation, it's clear that the best that could be expected would be for the flat washer rather than the bolt head to turn on the component...

A flanged nut or bolt is usually superior, with or without washer.