As I imagined, how to cut was not good.
Feeling that the core is not removed? Is not it.
I bought it because it is cheap in price, but the repeat is tough.
I wrote in comments because I do not want to evaluate it badly.
Used for grinding weld beads. As a result of various attempts, this product is used at present. I think that the grinding power is strong. Although I have used dozens of bugs, there is no defect such as core shake or core deletion, and it will not be too large to be lost largely. You can use up with confidence until the end.