??????? 50 Pcs Diamond Burr Set, 1/8'' Shank Stone Carving Set Diamond Polishing Kits for Rotary Tool Includes Dremel

1. On the new tools must be installed when the tool is to try whether the beating, to adjust to not jump to use. Otherwise the tool is quickly worn out, 2. Be sure to cool the water (like a drip device in a hospital), In case of dry drilling, the diamond on the head of the tool is graphitized by overheating, and it is quickly worn out. 3. When drilling, try to avoid shaking, because the shaking will cause local damage to the tool, and accelerate the damage of the entire tool.