You can safely drill a hole in a shell without causing it to crack or break. Shells are prized for their beauty and power to evoke memories of the ocean. Empty shells are used in a variety of crafts to add a natural accent. Aquatic-themed jewellery makers often drill tiny holes in a variety of small shells to attach them to a necklace or bracelet. Larger shells can be drilled to allow a hose to pass through in a water feature.
Clean the shell in hot water with a non-abrasive sponge to remove sand, barnacles and any other debris from its surface.
Draw a circle on the shell with permanent marker in the correct diameter and location for the hole. The hole should be at least 1/4 inch in from the edge of the shell.
Clamp the shell in place with a rubber-tip spring clamp or craft vice. Line up a clear path for the bit to pass through the shell without hitting anything else.
Load the drill or rotary tool with a small steel bit or one specialised for stone drilling. Work-station table mounts hold the drill or rotary tool in a steady position and are a helpful option for large drilling projects.
Rev the drill bit to near full speed before it makes contact with the surface of the shell for the first time. Bit tips are often wedge-shaped and will crack a shell if they are not spinning rapidly.
Change to progressively larger drill bits until the diameter of the hole is the correct size. Diamond-tip bits are more expensive than standard bits but work well to shave away the sides of an existing hole in a shell.