When cutting ceramic tile either for a floor or wall, using the proper tools becomes paramount. Along with the appropriate electric drill, the correct drill bit is essential to doing the job right.
Know the Tile
Before determining what type of drill bit you'll need, it's a good idea to know what type of ceramic tile you're dealing with. If possible, ask the salesperson of the retailer where you purchased the tile. Also, you can see if there's any information from the manufacturer about the tile. Ceramic tile is basically clay fired up in a kiln. The tile surface is usually coated with glaze--a silicon-based adhesive--for cosmetic and protective reasons. Knowing if the tile is glazed or unglazed will determine what kind of drill bit you should use.
If the tile is glazed then it's perfectly O.K. to use a carbide-tipped drill bit. Carbide-tipped drill bits are stronger than most other drill bits. Steel drill bits are ideal for wood surfaces, but the metal will most likely break against ceramic tile; carbide can penetrate ceramic tile with minimal pressure. The downside to carbide-tipped drill bits is that, depending on the extent of use, the tips may get dull quickly or too hot for continued use.
If the tile is unglazed, meaning it doesn't have a finish, or if you're doing extensive drilling, then it's best to use a diamond-tipped drill. Diamond-tipped drill bits originate from the mining business, where oil- and precious-rock miners bore into the earth. Diamond-tipped drill bits cost a little more than carbide-tipped drill bits, but they last longer; they also don't get as hot. For that reason, many fiscally minded drill users purchase diamond bits, figuring they'll get their money's worth over the life of the bit.