Which part of a twist drill is responsible for forming the cutting edges?

The flutes of a twist drill play a crucial role in the drilling process, primarily dealing with chip removal and the access of cutting fluids, but it is not the part that forms the cutting edges. The cutting edges are actually located on the body of the drill, where the spiral grooves originate.

The body of the twist drill consists of the cylindrical part that extends from the shank to the point. It features helical grooves known as flutes, which serve to reduce the weight of the drill and help guide the chips out as drilling progresses. The cutting edges are formed where the flutes meet the cylindrical body of the drill and taper towards the point at the end. This geometry is essential because it determines how effectively the drill will cut through materials.

The shank simply acts as the part that is held in the drill chuck and does not participate in the cutting action. The point is the very tip of the drill that penetrates the material, but it is shaped to provide initial penetration and does not encompass the full cutting surfaces responsible for material removal while drilling. This makes the body, particularly where the flutes and outer surfaces converge to form the cutting edges, the correct area related to forming those sharp edges essential for drilling tasks.