The pressurized cylinder parts in the six-face diamond press of our factory (Fig. 1), the annular groove in the large hole requires high precision and strict size. If the bottom of the tank is shallow, it will affect the assembly difficulties and serious damage to the rubber seal. If the bottom of the tank is deep, the rubber seal will expand when working, causing leakage and affecting the quality of the whole machine. To this end, we designed and produced the annular groove depth measurement tool shown in Figure 2 during the machining process to ensure the quality requirements, improve work efficiency and reduce waste.