Works great, tips are sharp and effective. I used them on a cast iron cylinder head to make some modifications. Ideally you want to use them in a drill press. I had to use a #8 countersink in such a way that it was inconvenient to place my work in the drill press, so I used a hand drill and a steady hand and it worked great. I will say my block of wood didn't have the word 'guilt' on it and the bits weren't engraved with 'guilt' so maybe I have a fake? Despite everything, the quality remains good. I look forward to using them again for more projects.