Cup burrs are great tools for filing the ends of wire. Cup burrs are a fabulous tool for making ear wires, ear posts, clasps and building chains. Cup burrs can save you a lot of time when fabricating your own jewelry or findings.
Recently, we have received a number of questions about which cup burr is the best to use for jewelry making. The answer, of course, is that "it depends" on the project.
Like most tools, there is no definitive rule about which cup burr must be used. The best cup burr is the one that works for you. With that said, I generally use a cup burr that is two gauge sizes larger than the wire I am using. For example, if I am using 20-gauge wire (.8 mm) or 21-gauge wire to create ear wires or posts, then I typically use an 18-gauge cup burr (1.0mm). If I am using 18-gauge wire, I usually use a 16-gauge cup burr (1.3mm). If I am using 16-gauge wire, I most often select a 14-gauge or 1.6mm cup burr.
Many companies sell cup burrs using metric measurements rather than wire gauges...so it is helpful to know the metric size of typical wire.
Wire Gauge MM