(a) Choose the largest possible diameter.(b) The minimum length of the tool holder is 2 times the diameter of the tool holder, and the best length is 3}- 4 times the diameter of the tool holder; the maximum overhang of the tool holder is 4 times the diameter of the internal turning tool holder, and the internal thread turning tool holder 3 times the diameter, and 2 times the diameter of the tool holder for the inner groove profiling machining; when the overhang of the tool holder is 4 to 7 times the diameter of the tool holder, a heavy metal tool holder or a full cemented carbide tool holder can be used.(c) Try to choose a fixture with strong rigidity to reduce the risk of vibration.(d) Coolant (or compressed air) can improve chip removal ability and surface quality, especially in deep hole machining.