Search:

It's the very thin washer between the tang and the scales. It's the one you don't see until you take apart a razor and the damn thing falls on the floor and then you have to crawl around on the...

Oh, I just remembered another use. I use one for slashing bread before baking.

Worst case scenario, I take it apart and hope that it at least has thrust washers! Sometimes that's the best you can hope for.