Tool joint thread roots and stress relief features, are cold rolled. Which is helpful to increase fatigue life by minimizing crack initiation. A hydraulic ram forces a roller into the thread root and follows the root down the thread sprial. The roller has the same contour as the thread root and the pressure between the roller and the root compresses the metal in the thread root. This compression of the fibers in the thread root results in a stronger connection that can withstand bending stresses longer without fatigue damage.