Under the premise of meeting the requirements of use, the lower tolerance grade should be selected as much as possible to reduce the processing cost. Please refer to Table 1 for the application range of tolerance grades, refer to Table 2 for the tolerance grades that can be achieved by various processing methods, and refer to Table 3 for the selection and application of tolerance grades.
In addition, when selecting the tolerance grade, the surface roughness requirements should also be considered.
For fits with basic dimensions ≤ 500mm, when the tolerance grade is higher than or equal to IT8, it is recommended to select the tolerance grade of the hole one level lower than that of the shaft; for fits with tolerance grades lower than IT8 or basic dimensions > 500mm, it is recommended to use holes of the same level, shaft fit.
