2. Secondly, when polishing, you need to pour a little water on the tile, and then cut off both ends for polishing. In the process of grinding, you need to pay attention slowly, otherwise grinding too many sizes will be inaccurate.
3. In the final polishing process, you can remove the whole waistline, then slowly cut a seam on the upper and lower sides of the waistline by hand grinding, and then knock off the waistline with a chisel.