Manufacturing method of hob drill bit suitable for finishing hole bottom rock surface of large-diameter socketed pile

The invention relates to the technical field of socketed piles, and discloses a manufacturing method of a hob drill bit suitable for finishing a hole bottom rock surface of a large-diameter socketed pile, which comprises the following steps: providing a rotary drilling barrel, and cutting off cutting teeth and cones at the bottom of the rotary drilling barrel to form a barrel body with a bottom opening; a bottom plate is provided, the bottom plate comprises a lower end face and an upper end face, inserted tooth hobs and roller bits are arranged on the lower end face, the lower end face is completely covered with the grinding tracks of the inserted tooth hobs and the roller bits, the bottom of the barrel is welded and fixed to the upper end face, and the bottom opening is covered with the bottom plate in a sealed mode; bottom cutting teeth and cones of a rotary drilling barrel on a rotary drilling rig are cut off, then a bottom plate provided with an inserted hob and a cone bit is welded to a bottom opening to