When you are building/remodeling a bathroom or kitchen like installing the faucet on counter top, you will need to drill holes through granite without cracking them, so you could use our diamond tip drill bit to make those holes very precise For a better finish and longer duration of the diamond drill bit,you could start on a slight angle to get through the top finished surface, then with light pressure carefully work through the granite. The average life of the granite hole saw depends on several factors,including the type of aggregate and material, its thickness/hardness ,proper cooling and use Note: Wear all applicable safety equipment when using these grinding wheel disc. - Eye protection (goggles)，Ear protection (earmuffs)，Hand protection (gloves)，Lung protection (dust mask) This is the ideal granite hole cutter for rock, DIY ,ceramic workers, construction workers, general contractors and tradesmen.