The 53.01.350 spring pack is mounted on the bar drawtube of the Gildemeister-DMG Mori GM16AC multi-spindle automatic lathe and is a key component of the opening and closing assembly of the main bar collet. From the shape of the part and its three front slots, the elastic working function of the springs is clearly identified, with the springs partially exposed so that coupling 5301346 can act directly on them in the axial direction during the collet closing phase. The spring pack is designed to keep the collet clamping pressure constant even when there are slight dimensional variations in the total length of the bar being machined, thereby ensuring stable gripping, reliable process repeatability and consistent workpiece positioning. In addition to supporting the closing load, the spring system also assists the reopening of the bar collet and therefore the correct feeding, clamping and release cycle of the material. Its kinematic role is not limited to simple elastic compensation, because it ensures the correct axial force transmission between the bar drawtube, coupling ring 5301346, the sleeve carrying the closing levers and the clamping elements of the main spindle. In this way the spring pack indirectly supports the entire operating chain of the multi-spindle machine, including the main spindles on the drum, the front toolholder spindles, the radial and axial slides and the auxiliary systems, since unstable bar clamping can affect cutting stability, turned diameter accuracy, concentricity and the overall quality of the finished part. Assembly is carried out with a defined preload adjusted through the hexagonal nut, an operation that requires proper technical skill because an incorrect preload changes the elastic response of the unit and can compromise both clamping force and smooth collet opening. Over time the springs may break due to fatigue or lose elasticity, reducing the effectiveness of the system and causing clamping fluctuations, dimensional variation, part sorting, increased scrap and, in severe cases, breakage of the bar collet, the bar drawtube or the tools. For this reason the component must be treated as a wear part, checked periodically and replaced in advance whenever instability or loss of accuracy appears on the machined parts. Replacing only the springs is not recommended if the maintenance technician or operator cannot correctly restore the preload of the complete spring pack. A minimum spare stock is also recommended and, when replacement is required because of wear, it is advisable to evaluate replacement on the other spindles as well in order to maintain uniform operating conditions; replacing only the affected unit remains mainly advisable in the event of a collision.