When youre using CBN wheels for internal grinding, you feel satisfactory compare with the grinding wheel that is made of AL2O3 or Sic. Vitrified CBN wheels has reduced manufacturing cost by increasing produce efficiency came from not only improvement on deviation of roundness, cylindricity and intensity of illumination but also enlargement of dressing interval. The maximum diameter size of CBN wheels for internal surface grinding is mormally very small because its size depends on materialss hole size. The revolution per minute(RPM) of CBN wheel for internal surface grinding is usually 20,000 - 50,000. Occasionally, it exceed 100,000 RPM. Therefore, the rigidity of machine should be enough to stand the swing of flange or shiver of itself