At the scrap yard they had a tri-wall container with a bunch of stainless steel disks. 4.25 inches in diameter and 5 mm thick and coated with diamond.. The disks are used to flatten silicon wafers. They came from DuPont. The back side has a few holes , some tapped to hold the disks on something.

To flatten silicon wafers they need to be pretty flat. They are not perfectly polished. But can almost be wringed together dry. With a little spit on them they wring together so well you can not pull them apart. You have to slide them so there is little area holding them before separating them.

Dan