Mechanics: fasteners: dished washer
Self-tutoring about fasteners: the tutor mentions dished washers.
I was noticing a washer described as “dished” and wondered why that might be. The following is as I understand it.
A dished washer is concave on one side, and perhaps has a flange on its other. The concave side is meant to be visible to the person installing it (once again, as I understand it).
Such a washer is meant to help align the bolt, as well as, perhaps, provide a seal around the hole, depending on the shape of the flange.
Source:
Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.