Livingston Jewelers

As a jeweler you really should be using metric drill bits. Period, end of discussion. But I decided that I should include additional information as it makes the discussion complete.
A common standard for metric drill sizes is the Renard series, which uses a simple factor to determine the diameter. I will not go into that as most jewelers use very small drill bits. I personally rarely ever use one over 5mm in size. for me, as a general rule, I tend to buy my drill bits in sizes that allow me to set round gems. The drill bits that I use every day range in size from 0.8 mm (0.0025 ct) to 5.0 mm (0.50 ct) in diameter and I tend to buy them in the sizes closest to the gems I set.

Some notes:

• The drill size chart below provides a list of standard size drill bits in several measurement systems.
• The first shaded column shows fractional, metric, wire gauge number, and letter columns. This table is split up into 4 sections as it would make a very long list on the page otherwise.
• The second and third columns show the decimal equivalents of the diameters are shown in both English and Metric units.
• Fractional sizes are measured in inches, while metric sizes are measured in millimeters.
• The wire gauge and letter systems refer to tool diameters that increase as the wire gauge decreases from #107 to #1 and then continues from A to Z. Number and letter gauges for drill bits do not follow a formula or standard increments. They are loosely based on the Stubs Steel Wire Gauge, with gauge sizes that are similar (but not entirely identical) to that system. Although they originated in the 19^thcentury, these gauges are still commonly used in the U.S. They are also seen in the UK to a lesser degree, having been largely replaced by metric sizes. Most other countries, especially in Europe, have abandoned them entirely in favor of metric systems.
• The drill size chart contains tools up to 1.5 inches in diameter, but larger tools are also commonly used.

Standard metric drill bit sizes