In our country's mining resources, underground mine resources account for a large proportion. The mining of underground mine resources must be based on the production conditions of the mine, using different drilling and blasting mining techniques. Generally, underground mining can be divided into three forms according to the depth of the drilled blast holes: shallow hole drilling (hole depth 6m), medium-deep hole drilling (hole depth 10~30m), and deep hole drilling (hole depth 50~60m). Among them, in shallow hole drilling, for blast holes with a diameter of less than 43mm, H22mm tapered connecting rods and straight, cross, or spherical tooth drill bits are usually used; for blast holes with a diameter greater than 43mm, R32-H25-R32 x 1000mm lightweight connecting rods or R32-D32-R32 x 1000mm connecting rods are used, along with cross or spherical tooth drill bits. In medium-deep hole drilling operations, R32-D32-R32 x 1100mm and 1200mm connecting rods are mainly used, equipped with cross drill bits and spherical tooth drill bits with diameters of 55mm and 60mm, as well as T38-D38-T38, 1220mm, 1830mm T45-D45-T45 x 1525mm, 1830mm connecting rods and MF rods, along with 64mm and 76mm spherical tooth drill bits. Deep hole drilling is mainly used for staged mining methods, with the diameter of drilled blast holes usually over 100mm for horizontal deep holes or downward deep holes, with a maximum depth of up to 165m, usually using high-pressure down-the-hole drilling tools. Currently, most underground metal mines in our country use medium-deep hole drilling, so connecting rod tools have become the main drilling tool products used in underground mining. R3212-D32-R3212 x 100mm, 1100mm, 1200mm connecting rods and 55mm, 60mm, 65mm, 70mm diameter spherical tooth drill bits are the most widely used types of drilling tools for medium-deep hole drilling in underground mines, and these tools are equipped on the guide rail-type pneumatic rock drills (mainly YYG90 type machines) for drilling operations.