I have been trying to mirror-finish some 2x3 1/2
inch 14g copper pieces. First with 400 paper,
then 600 and all to way to 4/0. Then black emory
through white diamond. This is about the time
deep little marks appear in the copper. The
lines appear to be in the axis of the polishing
wheel. Being a large piece it is easy to get it
I suspect the heat generated during the white
diamond phase is pitting the metal.
Has anyone else experienced this problem?