Review on SCOTTCHEN 8 Inch Diamond Flat Lap Wheel - 1/2 Inch Width - 240 Grit for Grinding, Sanding, Lapping, and Polishing Disc by Brett Blazis

I ordered one and even had to replace it. But the replacement was no better. Most of the wheel is 600 grit, but there are larger diamonds scattered throughout, causing the work to be scratched like a 120 wheel. You can see the picture under the microscope with the two larger (yellow) diamonds and the rest of the suitably sized diamonds can still be seen under the nickel layer. . You can also see the before and after of some synthetic rubies. Before: 400 grit SiC left a smooth surface, but after just a minute on this 600 grit wheel, the surface was white with scratches even rougher than 180. Don't buy higher grit, they didn't pass quality control. .However, the 180 grit sanding disc I bought from this seller was phenomenal and I will keep it for years to come.