12 Pearl Drill Bits & Stand Great for Metalsmiths, Metal Working & Drilling. This new set of 12 pearl drill bits. Great for drilling holes, setting seed pearls and other round or half round stones. Comes with a plastic base and cover to keep the bits organized. Each has a steel 1/8" (3.2 mm) shank. These bits measure from approximately 1/16" to 1/8" (1.05 to 3 mm).