为了有效的加工M5×2方牙螺纹(图1),我们采用了保护套(图2)。这种保护套十分简单,安装在顶尖3的颈部,用螺钉3紧固,防止转动。保护套5用T8A材料制成,热处理后HRC=58～62。工件与保护套成2级精度滑配合。顶尖颈部要求较长,与60°及莫氏锥度部分同心度小于0.01毫米,并与保护套成紧滑配合。 In order to effectively process M5 × 2 square thread (Figure 1), we use a protective cover (Figure 2). This case is very simple, installed in the top 3 of the neck, with screws 3 to prevent rotation. Protective sleeve 5 made of T8A material, HRC after heat treatment = 58 ~ 62. The workpiece and the protective sleeve into a 2-level precision with the slide. Top neck longer, with 60 ° and Morse taper part of the concentricity of less than 0.01 mm, and the protective sleeve into a tight fit.