You need a Dremmel® tile-cutting tip and a round jig made of plywood. Keep in mind that the tip is designed to be used with that company’s drill motor. Not all motors run at the same revolutions per minute. Also, there is a guide housing that only fits a Dremmel® motor. Once you have the proper tool the rest is a breeze. Here’s what to do: · First, cut a jig from a thin sheet of plywood or Masonite. Keep in mind that there will be a small offset between the edge of the tool and the bit. Practice on a broken tile until the jig is just right. · Next, clamp the jig to the tile and make your cut. The easiest part of the project is actually making the cut. The Dremmel® is not a very large tool, but it is the only one that we know of that can solve your problem.