Referring to FIG. 4A, it can be seen that the tail 31 supports the abrasive particle 2. [32] [33] Although the length of the tail 31 depends on the conditions given, it is effective when it corresponds to about 5 times the size of the abrasive particle 2. [34] FIG. 4B is a schematic view taken in the thickness direction of a cutting tip, illustrating one abrasive particle and the surrounding there