三爪卡盘使用日久会出现同轴度降低及喇叭口现象，直接影响加工精度及装夹可靠性。实践证明，用以下方法修正，简单实用，效果显著，不妨一试。以正爪卡盘为例，先用外夹的方式夹紧一段适当直径的圆棒，开动机床，车削卡爪的外圆部分。然后用内撑的方式夹持一环形件，开动机床 Three-jaw chuck discoloration will occur with the concentricity and trumpet phenomenon, a direct impact on machining accuracy and clamping reliability. Practice has proved that the following methods to amend, simple and practical, the effect is significant, may wish to give it a try. To the jaw chuck, for example, the first method of clamping the outer diameter of a round bar with a suitable diameter, start the machine, turning the outer jaw part. Then hold the ring with a way to hold the ring, start the machine