- 1). Mount the diamond core bit into the drill. Follow the manufacturer’s instructions on how to properly slot the drill bit into the drill and how to tighten it, as different drills have different sets of instructions. Make sure the drill bit is completely locked in place, otherwise it will spin inside the mounting of the drill and will not cut through the surface of the porcelain.
- 2). Measure with the tape measure to determine where your hole needs to be cut and use the marker to make a dot on the surface of the porcelain. Remember that the core bit needs to be centered on the area will you will be cutting the hole, so mark the center of the hole you plan on removing or cutting out.
- 3). Cover the area you will be cutting with masking tape. Two to three layers should be sufficient for your needs. If the tape conceals your mark from earlier, simply transpose the mark onto the surface of the masking tape. The tape will keep the diamond core bit from slipping all over the face of the porcelain and marring the surface. By digging into the tape first, the center of the core bit will remain locked in place long enough to dig through the hard surface of the tile, thus allowing for the actual outer rings of the core bit to cut through the tile.
- 4). Start with a low speed until the center section of the drill bit has sunk into the face of the tile and thus locked itself in place. If you use a high speed to start off with, you run the risk of losing control of the drill and scratching the surrounding face of the tile or even other pieces. Once you are sure the drill bit has made it into the face of the tile you can proceed to use the drill at full speed until you have cut your way through the entire tile.
- 5). Avoid cutting through the substrate behind the tile. While it takes some guesswork to determine the thickness of the tile unless you can see a visible edge, the average piece of tile is anywhere from 1/4 to 3/8 inch thick, so slow the drill down when you think you have made it through the tile unless you actually want to cut through the surface behind or underneath the tile as well.
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