Fastest way to grind enamel between firings

I am working with enamel on copper tiles on a big piece and need to
figure out the fastest way to grind pieces, ranging from very small
to large irregular shapes, in between firings. Have checked out
lapidary equipment on craigslist but I have a small space and not
sure I need so many different grades. Anybody with the same type

Karen in Corvallis