I bought them to use with my machine with CNC 3018. The first bit broke after a few minutes. I carved a red oak cross. The depth of cut was 0.5 mm. At first I thought I made a mistake that broke the racquet. When I opened the container to choose another bit, I accidentally dropped 4 bits on the floor. They fell about 2 feet to the floor (I was sitting in a chair at the time). One of the pieces broke when it fell on the floor! The material is of very poor quality. I'm giving this product 2 stars because I haven't tried any other bits yet. I'll test them on a piece of wood and if another piece breaks I'll reduce my rating to 1 star.