How something as small as a fountain pen nib is produced?

The "steel nib" of a neutral pen is a type of nib that is also known as a "full-barrel" nib. It is machined in a non-cutting way. Before it is processed into a nib, it is a complete thin tube, which is formed into a bowl seat for the ball by hitting three concave points in the front of the tube from three directions with a precision instrument, while the thin tube at the back forms a triangular oil groove. The ink flows out through the oil grooves, and then the ink is brought out through the rolling of the balls to complete the writing process. The syringe type is suitable for the manufacture of finer nibs, such as 0.30, 0.25, and so on. Semi-cylindrical is between the bullet and the syringe, the tip of the nib can be as thin as a syringe, while the end of the nib is the same size as the end of the bullet. Semi-cylinder type can make relatively thin nibs, such as 0.48, 0.35 and so on.