A tile drill bit is a special masonry bit designed to drill holes in ceramic tile and other very hard surfaces. Ceramic tile is a very useful material because it is extremely durable and entirely impervious to water and many other common household chemicals. Tile is both extremely hard and very fragile and can be difficult to work with. Special tools are often required. A tile drill bit spins very rapidly and gradually abrades a path through the tile, rather than cutting a path through it, as would a drill bit punching a hole through wood. Two different types of tile drill bit are available: carbide-tipped and diamond-tipped.
Masonry bits tipped with carbide can be used as tile drill bits. These bits will take a relatively long time to drill through tile, but are generally economical. Drilling through ceramic tile is difficult, so these bits have a fairly short lifespan, and several may be required to complete a project.
Diamond-tipped tile drill bits are more rugged than standard masonry bits. Diamonds are exceptionally hard, and diamond-tipped bits, as a result, are very effective. They are also, unsurprisingly, more expensive, but some of this added expense is made up for by the fact that diamond-tipped bits can be expected to last much longer than ordinary masonry bits.
Drilling through ceramic tile is difficult, even with a high-quality tile drill bit. The surface of ceramic tile is very slick, and while this characteristic is one of the reasons why tile is so useful and popular, it makes using a tile drill bit very difficult. Starting a new hole in ceramic tile is particularly difficult because the bit will have a tendency to slide away from the desired location. Using a jig made of wood or metal to hold the tile drill bit in place can be very helpful.
Although a hammer drill is the right tool for using a masonry bit to drill through cement and brick, it is the wrong tool to use with a tile drill bit. A hammer drill produces a very rapid pounding motion, and this motion, while useful in drilling through stone or brick, will crack or shatter ceramic tile. A normal drill should be used with a tile drill bit. Also, while using a tile drill bit, it is important to remember that they are prone to overheating. Tile drill bits work by grinding away the tile, so the drilling generates a great deal of heat. Drilling slowly and using water or oil to cool and lubricate the drill bit are imperative.