A counter sink has a major cutting edge at its end, while spiral flutes have a bevel angle, which is known as rake angle, at their tip. In order to ensure good centering and guidance of this drill, it has a guide post at its tip that fits snugly into the existing hole in the workpiece. To make clamping easier, the tool shank is cylindrical and the head is tapered with an oblique hole. Its tapered tip has a beveled edge which is suitable for cutting purposes. The through hole serves as a chip discharge hole, allowing the iron chips to rotate and be discharged upward. The centrifugal force is helpful in scraping off the iron filings on the surface of the workpiece to prevent scratching the surface and affecting the quality. There are two types of guide posts, and countersunk holes can also be made in one piece if necessary. The purpose of the countersink drill is mainly countersink and processing smooth holes. Its design and structure make it easier to work efficiently and improve the quality of the final product.