Drilax 8 Inch Diamond Flat Lap Disc 1200 Grit | 8" x 1/2" Arbor Hole | Single Sided Diamond Lapping Pre-Polishing Wheel for Lapidary, Gemstone, Glass, Stone Finishing | Solid Steel Base

I ordered an 800 and 1200 grit disc for my lapping machine to lap alumina. Both discs looked okay and the 800 one worked okay. It was relatively flat and cut smoothly. However, the 1200 grit disc was not flat and the coating was not as uniform. This meant that it had to be broken in longer until it cut consistently but it still was not flat (the steel disc is not flat and so although it could be used to obtain a decent surface finish on a small part it would not work well to lap a larger part flat.

These have a very short life and had varying size grit on the plate which just scratched all my stones and put me back to square one.

ok