Shaping cut-outs and drilling holes
Another curve-cutting approach, ideal for thicker stone and ceramic tiles or cutting a large hole for a toilet, calls for an angle grinder with a continuous-rim diamond blade, held vertically to follow a cutline. Cutting dry creates hazardous dust (wear a mask), and heat and vibration that can crack tiles—go slowly, with multiple passes.
To make straight plunge cuts for, say, an electrical box cut-out, use an angle grinder and a diamond blade, or a water-lubricated, hand-held tile saw. Another technique: Bore overlapping holes along the cut-out edge with a diamond coring bit, then nibble off the leftover bits with tile nippers.
You can drill a hole in the middle of a tile with a carbide masonry bit, and carbide-encrusted hole saws are available, but for ease and speed, the best option is a coring bit rimmed with diamond fragments. Unlike a hole saw for wood, it won’t have a centre spur to hold it in place. Until the bit has scored the tile surface, it tends to skate around. Scrap plywood with a V-shaped cut-out works as a jig to steady the bit, as does an adjustable wrench opened to the size of the bit. Cool the saw and tile with a spray bottle or squirt gun, or form a ring of Plasticine or window putty on the tile, and fill it with water.
How to lose your edge
When you cut tile—especially glass—the edges can be sharp or jagged. Smooth them with a few quick passes of an inexpensive diamond sharpening stone dipped in water.