Review on 🔩 Bosch CST1 Titanium Coated Countersink: Superior Performance for Precise Countersinking by Rick Everett

This countersink is excellent in design and material; The five groove design minimizes vibration and is made from solid steel that is suitable for both metal and wood. The design is especially important when used with a hand drill, as it will cut a smooth hole even by hand (although results are obviously better with a drill). The quality is only decent; As other reviewers have pointed out, there were slight burrs and nicks on the cut edges. Not enough to make a big difference when cutting wood, but it does make an impact when cutting metal. However, I was able to clean the edges fairly easily with a fine grit whetstone, and after that it cut through mild steel with no problem. I've also sharpened it more than once in the couple of years I've had it after it has dulled from lots of drilling through metal. I had to carefully sharpen each groove the same amount to avoid an imbalance in cutting action, but all it took was keeping track of where I was sharpening and where not. The drill cuts well and smoothly after regrinding.