Master Wholesale President Blake Adsero shows you how to wet drill a hole in porcelain tile with a porcelain diamond drill bit. You will need two small pieces of plywood and a wood cutting drill bit of the same diameter as the wet cutting diamond hole saw bit.
First you drill a hole in one of the pieces of wood placing the other piece behind it so you don't drill into your work surface. This hole will serve as a pilot hole for the diamond bit to stop it from moving around as you start to drill your hole in the porcelain tile.
Next switch to the porcelain bit and place a piece of wood under the tile and line up the one with the pilot hole to where you want your hole in the porcelain tile. Pour a little bit of water in the pilot hole and then start drilling. Once you have started the hole, you can remove the plywood guide, add a bit more water and continue drilling. You may need to add water a couple more time before you are through the tile.