H.S.S. Graver: HSS Gravers are more difficult to sharpen than Carbon Steel, but the cut quality and long lasting edge is worth yourtime and effort. Round : Used for Bead - raising, block lettering and line engraving. Onglette : Used for setting stones, line engraving inlay work and borders. Flat : Used for lettering bright, cutting, background removal and stylish borders. Knife : Used for fine line engraving, deep E and narrow cuts, inlay work stone setting.