Shaping natural nails, you’ll want to make sure that you use nothing coarser than a 180-grit board file. Use an emery board or a ~200-grit nail file as much as possible. Using gentle grit files will keep the natural nails from splitting. Not only do splitting nails become weak but also causes your nail polish or gel to chip. Click the link to read more about this topic. https://paolaponcenails.com/shaping-natural-nails-squoval-round-oval-almond-coffin/