Small-diameter drill bits typically have no neck. The working part includes the cutting part and the guiding part. The cutting part has two main cutting edges, two secondary cutting edges, and a transverse edge. The helical groove of the guiding part is used for chip removal, chip storage, and guiding the drill bit for linear feed. They can be divided into high-speed steel twist drills, carbide twist drills, cobalt-based twist drills, and so on. They are widely used in the construction industry, woodworking, mechanical processing, and other fields, and can perform drilling operations on various materials such as concrete, steel, and wood.