Tile is hard, glazed and brittle, so the wrong bit skates across the surface or cracks it clean through. The best drill bits for tile are diamond bits for porcelain, stone and glass, or carbide spear-point bits for softer ceramic and wall tile. Here is how to choose and drill without cracking a single tile.
What to Look For
Tile is not drilled by cutting a chip — it is ground away by abrasion, so the bit must be harder than the glaze and the body beneath it. Diamond bits carry industrial diamond grit that grinds through the toughest porcelain, quartz and glass without any hammer action, which would instantly shatter the tile. Softer glazed wall ceramic can be started with a carbide spear-point bit, whose sharp arrowhead scores through the glaze and into the softer body. In both cases heat is the enemy: friction builds fast, and these bits must be kept cool with a steady trickle of water or they burn and the tile cracks from thermal shock.
The Best Type of Bit for Tile and Porcelain
For hard porcelain, natural stone, quartz and glass, choose a diamond bit — only diamond grit reliably grinds through dense porcelain. For softer wall ceramic, a carbide spear-point bit cuts a clean start. Never use hammer mode on any tile.
- Porcelain and glass: Diamond bits grind through the hardest, densest tile.
- Soft ceramic: Carbide spear-point bits start and cut wall tile cleanly.
- Keep it cool: Feed water constantly — heat cracks tile and kills the bit.
- No hammer: Rotation only; hammering shatters the brittle glaze.
Technique and Mistakes to Avoid
Stop the bit walking on slick glaze with a strip of masking tape or a drilling guide over your mark, and start at a low angle before slowly bringing the bit upright once it has scored a groove. Use light pressure and let the abrasive do the work — forcing the bit only overheats it and risks cracking the tile. Keep the tip wet the whole time, dipping or dribbling water to flush the dust and carry away heat. Ease right off at breakthrough, and support the tile from behind if it is loose. Our USA-made diamond bits drill porcelain and glass cleanly without cracking.
Drilling Near Edges and Fixings
Holes near a tile edge are the most likely to crack, so keep at least an inch of margin from any edge or corner where you can. When you must fit a fixing, drill through the tile first at low speed, then swap to a masonry bit to carry the hole on into the wall behind — never let the diamond bit hammer into the substrate. Fit the anchor into the wall material, not the tile itself, and use a soft washer under the fixing so tightening it never puts a crack-inducing load on the glaze.