The selection of tool holder has certain requirements. Because the quality of tool holder will directly affect the function of the machine tool and the processing power of the whole CNC lathe, the method of mastering the demand of selecting tool holder is introduced below.

     The selection is based on the shape of the handle of the NC lathe. According to the requirement of tool changing, spindle holes of boring and milling CNC lathes and their machining centers are mostly selected as taper of 7:24 without self-locking, but the shank matched with machine tools is not completely consistent. Some shank has a cylindrical head at the small end of 7:24 taper. Others do not, which is obviously incompatible with international norms. As for the specifications of the East-West shank for the active tool changer machine tool and the spindle hole of the machine tool, it should be determined that the selected machine tool should be equipped with the East-West shank which conforms to the specifications. The selection of tool shank is required to be in accordance with the specifications of machine tool spindle holes (No. 30, No. 40 or No. 45). Moreover, the grasping position of the tool handle should be able to meet the requirements of the shape and orientation of the manipulator, and the shape and scale of the pulling nail should match with the tension mechanism of the spindle.

    According to the processing technology of typical parts on CNC lathe. The number of tool shanks used in CNC lathes for drilling, reaming, boring, milling, tapping threads and other purposes will reach hundreds of specifications. And the user only purchases a detailed machine tool, the user can only select according to the processing technology of typical parts to be processed on this machine tool. In this way, it can satisfy the basic processing needs without forming a backlog. It is a useful and close selection method.

    According to the number of tool holders matched. The matching number of tool shank is related to the variety, specification and quantity of parts to be processed by machine tools, and also to the degree of disorder and the load of machine tools, which is generally 2-3 times of the required number. Considering the machine tool operation, a certain number of tool shanks are being pre-adjusted or trimmed. Only when the machine load is scarce can it be twice or less than twice. The capacity of tool Bank of machining center is 2-3 times that of general active machining requirement.