The diamond core bit is used to drill holes in: •Ceramic tiles •Marble •Grade 5 porcelain (hardest) •Granite •Glass •Slate The diamond core cuts faster, smoother, and lasts longer than any other core drills The diamond core drill bit must be used with water at all times when drilling. The water serves as a coolant to prevent the diamonds from overheating. The maximum allowable temperature for a diamond core bit is 500°C. There is no pilot drill with the diamond core bit. A low rpm rotary drill with a planetary gearbox is required to be used with a diamond core bit. It is possible to use a cordless drill but in the lowest gear setting. No hammer action is used.