Carbide drill bits are wonderful in the way they just kind of melt through metals like platinum or harder white golds. Clean, bright cuts, round holes. No dull drills. But, and it's a big but, these things are more than just a little fragile. While the short length helps, they're still very easy to break with even a slight error. When I first tried these, I managed about two holes per drill before breaking them. I've gotten better. But use them gently, well braced so you don't bend or torque them, and at high speed only (very important). Much more than carbide burrs, you really need to use them at high speeds and with a precise touch, or they'll not last long enough to justify their higher cost. Don't forget a good lube. If/when you break them, if the broken tip is stuck in the metal, it can be dissolved with fresh pickle, just like a high speed steel bit.