HELP Lapping a Surface Plate
Aug 23, 2017· I think some diamond powder got loose and got stuck in the pores of the granite. I am using 20 to 40 (micron?) sized diamond. When I first started, I used 325 grit, but I ran out of it. I roll the diamond powder onto the granite lap with a steel roller, and then brush off any excess, and then wipe it again before lapping.