We bought a drill bit with a crown. Drill bit (diameter 14) - 277.52 dollars and soldering 4 pieces at 73.68 dollars /piece. They promised that soldering with the modes set will take care of 2000-2500 drills of our part. In practice, soldering stood for no more than 800 drills. And on the last soldering, after 200 drills, the drill bit in the part broke. After the official appeal, they were led by the nose for more than 3 weeks, and after that they began to freeze at all, they said that we violated the processing modes. When we offered them to come to us and do all the necessary tests with a new drill, they refused. It's expensive and there's no drill!