Review on 🔩 Bosch CST1 Titanium Coated Countersink: Superior Performance for Precise Countersinking by Daniel Truett

I have had to countersink the screw heads into the breech plug stocks of several flintlock rifles I build. This is unhardened steel. It does the job superbly. Chatter is mentioned in some reviews. You need to find the right RPM to get the smoothest cut on the test hole before you start the final finishing. However, once a steady cutting speed is found, this tool will live up to expectations. I've only used it on five holes but it's still as sharp as it was when it arrived.