A hard abrasive removes material from metals such as hardened steel, titanium, and iron. It also leaves a cross-hatch patterned finish to retain lubricant. These hones have abrasive-embedded balls mounted on flexible spindles that press against the inside of cylinders. Hones are slightly oversized for maximum contact. When your cylinder ID falls between two sizes, order the larger hone. Use with portable drills, drill presses, and CNC machines. Hones should be rotating when inserted into or removed from cylinders. We recommend using them with honing oil to keep the abrasive free of debris.