Review on 🛠️ Cobalt Twist Drill Bits 6.5mm: Premium Quality and Precision for Efficiency by Bobby Frazier

You are perceptive and honest. They have cobalt in the metal, making them prone to edge cracking when they touch the last part of the cut. If you use a hand drill, this is what you expect. I was able to pierce the track bolts (grade 8) on the main link. If I had paid close attention to the pressure I was putting on the drill I would not have had any problems with the cutting edge breaking. I've never broken anything other than the cutting edge which was my fault overall, especially for the price.