First response winner! Yes, I've heard that their value/utility is questioned. Would be interesting to see a study on it.
Regardless, I suspect there is a specification for these type of washers that isn't met; probably a mil-spec as a guess.
If anyone knows of specs particular to these type...
Previously sent this to a bunch of folks in my personal e-mail lists with varied results/feedback.
Curious to see what the Eng-tips audience says of these: