In actual production, we often encounter the parts shown in Figure 1. The assembly uses are shown in Figure 2. In order to achieve a good sealing effect, the large-mouth size of the tapered surface generally has tolerance requirements, and the tapered surface generally has surface roughness. The requirements of the end face have processing requirements, but the actual taper drilling is used in the actual production, it is difficult to ensure the tolerance requirements of the taper large mouth size and the surface roughness of the tapered surface. To this end, we have designed and manufactured a composite tapered reaming drill, which has a good application effect.