How a Drill Hole of a Pearl or Stone Bead can be enlarged ?
Pearls or stone beads are usually half-drilled or fully-drilled to a standard hole-size of ca. 0.7 mm to 1 mm.
If pearls or gemstone beads are already half or fully drilled, it's really easy to open them up just a bit with another drill bit that is the correct size needed for your design.
There are many battery-driven or manual hand reamers on the market; all work very well.
Simply hold the pearl or bead between your fingers and drill.
You can practice on cheap freshwater pearls or beads first, and test frequently to see if the hole is large enough.
To drill harder stone beads just put a little water in a shallow dish and keep the bead submerged in water.
A bead reamer is a handy and inexpensive tool to have on hand.
Bead Reamers sold on eBay