Among other operations, we also perform cold rolling of threads using a Koller hydraulish machine. Cold rolling is the process of plastic deformation of metal by an amount of 0.05-0.12 mm, using a rotating roller . The energy required for deformation is transmitted through a roller connected to the hydraulic cylinder. During the operation of the threaded connection, the greatest load falls on the root of the thread. Rolling creates a compressive stress at the root of the thread, smoothes the bottom surface and reduces microroughnesses. This procedure reduces fatigue stresses and thereby increases the service life of a threaded connection by 3-5 times. Rolling is used for both pin and box connections.