Abstract: A groove forming process for forming at least one groove pattern on the outer diameter of a shaft for use in a hydrodynamic bearing of a spindle motor. First, the shaft is inserted between a pair of dies, at least one of which has a groove pattern thereon. Next, the shaft is positioned so that it is perpendicular to the groove pattern and at one end of the groove pattern. By lowering the upper die, the shaft is clasped between the dies. The shaft is then rolled in a first direction over the groove pattern by simultaneously applying pressure in a vertical direction and applying pressure in a first horizontal direction to one of the pair of dies so that the shaft rolls in the first direction. The shaft is then rolled in a second direction over the groove pattern by simultaneously applying pressure in a vertical direction and applying pressure in a second horizontal direction to one of the pair of dies so that the shaft rolls in the second direction.