Diamond twist drill bits for enlarging holes in glass, beads and pearls.

Available in sizes from 0.75mm to 3.00mm with a straight shank, these micro drill bits are coated in diamond grit for use on hard materials such as glass, stone, ceramics, porcelain and shell.

Unlike standard drill bits, these are designed specifically for widening and refining existing holes rather than drilling from scratch. The diamond grit runs along both the tip and the sides, allowing them to remove material smoothly in both directions.

Ideal for bead makers, lampworkers and jewellers, they are especially useful for enlarging holes in pearls and glass beads with precision and control.

They are also used in industrial settings, including ceramic work. For a handy trick, a 3mm twist drill can be used to demist double glazing by drilling a small hole in the bottom corner.