Tool Holder Standard  SK (DIN 69871/DIN ISO 7388-1)

Germany Shank specifications: The shank has 30, 35, 40, 45, 50, and 60 specifications, which indicates the diameter of the taper shank somewhere

(the specific location is different in different standards).

The specifications of the cone are usually selected by the machine tool manufacturer based on the effective power of the machine tool or the overall length of the tool used, and are also related to the country of production (DIN standards in Europe, ANSI standards in the United States, and JIS standards in Japan).

The commonly used shank specifications are 30, 40, 50, of which 40 is the most widely used.