HBM Drill Sharpener, Drill Grinder From 3 to 13 mm In just three simple steps, you can ensure that blunt, worn drills are extremely sharp again. The grindstone at the drill grinder consists of diamond and is therefore extremely hard. That way you always achieve the desired results quickly. You can be sure of a good result, especially with HSS drills. In this way, this device is perfect for use in industrial workshops. Furthermore, the sharpener is suitable for use on just about any type of drill. So it is a flexible tool.