this is not a defect

Gokumyo stones are universal and can be used to sharpen knives of any steel including high carbon

Remove the assembly screw

The TSPROF attach for convex sharpening of blades is provided as a removable adapter

Estimated grit for Bluestone is approximately 6000 JIS

suehiro rika 5000 edge pro this is not a defectRika 5000 sharpening stones are used for sharpening knives on Hapstone and Edge Pro knife sharpeners. Rika stones are made of aluminum oxide. All Rika stones are 5 6 mm thick and are mounted on high quality aluminum blanks. Rika is part of Suehiro traditional Waterstone series which includes Kouga 3000, Rika 5000, Shiramine 6000, W8 8000 (Junpaku) and G8 8000 (Takeiro). These stones are not available in a wide range of grits. Traditional series does