When we mill the workpiece groove shown in Figure 1, the cutting fixture is used, and the effect is better. The live tip 7 (Fig. 2) in the fixture is made from a common tip. The shaft of the ordinary live top can be removed first, and then the extension shaft of the rear top plate 5 can be attached. The front top plate 2 and the rear top plate 5 respectively take the outer circle at both ends of the workpiece as a positioning reference. A mandrel with a diameter of φ12 mm is arranged at the center of the front end, and when the workpiece is clamped, the front top plate 2 and