Utoolmart 1-2mm Diamond Twist Drill Bits High Speed Steel HSS for Glass Sea Shells Stone Tiles 10 Pcs

The diamond drill bits will generate a lot of heat energy during high-speed rotation. Please add water to cool the drill bit, otherwise the temperature will be too high and the diamond particles will fall off. Made of HSS twist drill bit and then electroplated diamond particles, so the part of the drill edge will be thicker. This diamond twist drill bits can not be used for grinding. The coating of the diamond drill bits after the grinding has been damaged, and it can only be used as an ordinary HSS drill bits.