What does it mean that the normal machining accuracy of machine tools can reach IT7?

It is the code of the standard tolerance level, and the standard tolerance is the level that determines the dimensional accuracy. There are twenty standard tolerance levels, from IT0 1, IT00, IT0, IT 1 to IT 18. The grade decreases from IT0 1 to IT 18, and the standard tolerance value increases in turn to IT066. IT7 belongs to the medium tolerance level. When you say that the normal machining accuracy of the machine tool can reach IT7, you mean that the machining dimensional accuracy of the machine tool can reach the medium machining accuracy.