How to Enlarge and Shape Holes in Tile and Stone

Sometimes a drilled hole is close but not quite right. Enlarging or rounding it cleanly takes the right tool and a light touch. Here is how to shape holes in tile and stone without cracking them.

Start with a predrilled hole

Finger bits refine, they do not start. Drill your initial opening with a core or masonry bit first. Then a diamond coated finger bit steps in to enlarge, round or smooth that hole to size.

Pick your mounting tool

Many finger bits thread onto a 5/8-11 angle grinder for control, or run from a drill with an adapter. Choose the tool you handle most steadily, since precision matters more than raw power here.

Work wet where you can

Wet milling cuts heat and dust on dense porcelain, marble and granite. It keeps the diamond coating cooler and the surface cleaner. If you work dry, pause often to let the bit cool.

Respect the speed range

Diamond bits have an optimal RPM window, often around 6000 to 11000. Too fast wears the coating quickly. Match your tool speed to the maker's guidance for clean cuts and longer bit life.

Ease into the shape

Light, patient passes beat forcing the bit. Let the diamond do the work as you widen or round the hole. Gentle pressure protects both the tile and the coating.

The bottom line

Drill first, then refine. Pick a steady tool, work wet when possible, mind the speed and take light passes. That approach shapes clean holes in tile and stone without cracks.