Granite requires diamond grinding wheels to smooth and shape it. A four-inch angle grinder is usually the tool of choice, as it allows you to grind larger areas in relatively little time. Compact areas can be worked using smaller hand-held carvers with the appropriate diamond bits. Both types of tools are also used to polish and finish a granite surface. Depending on your tools, you can grind wet or dry. Wet grinding requires specialized tools.
Place the stone where you can easily work the surface in a well-ventilated area: dry-grinding will produce a lot of dust. Safety goggles and a mask are required, even if working outdoors. Attach a vacuum system to the grinder if working indoors.
Attach a diamond grinding disk to the angle grinder. Use a grit of about 100 to start. Try running the grinder at about 1500 rpm and keep a firm grip as you begin to work the stone surface. Hold the disk flat against the surface and move it slowly in a controlled motion.
Create beveled edges on the stone by running the grinder along the edges at the desired angle. Remove the surface in thin layers until you have rounded the edge. Once the surface has been evenly ground and shaped, replace the disk with a finer grit.
Continue until you are satisfied with the surface; use up to 3000 grit if desired, before you begin to polish. Do not use water unless your grinding tool is built for it, as this can ruin the grinder and cause electric shock. Grind the entire surface thoroughly with each change of grit.
Grind hard-to-reach areas with a small electric carver. Use diamond bits and wheels to cut and grind small areas, as well as to polish. Always start with a rough grit and work your way up to finer grits. This will eliminate scratches and tool marks from the previous grit used.
Polish the granite using diamond polishing disks to give the granite a very smooth finish.