I normally use sandpaper on glaas for sharpening my chisels and handplanes.. I recently bought some diamond grit paste from LV no 6 micron which wouild compare I think to a coarse grit in sandpaper. I have tried using a cast TS surface and on a piece of maple. I am not getting the expected results when compared to sandpaper, seeminly not half as fast. Is this normal?