The Risk of Hand Tightening Screws

According to DIN 8593 "Manufacturing Process Joining", screwing is the most widely used method of joining in the mechanical engineering and in the automotive industry. This is also the reason why the reference from Leonardo da Vinci is current in the technique of mechanical joining of parts using threaded fasteners. Leonardo's compass and rudder in this case is the exact tightening of screw connections. As will be seen from the following text, the correct pre-stressing force can only be achieved by controlled tightening. Hand tightening by feel, so often preferred in practice, is burdened with a subjective factor that cannot be predicted, and therefore it represents a latent danger of disintegration of the entire structure.