The 15.01.611 screw is the fixing component that locks keys 1501606 onto sliding ring 1501604 in the Gildemeister GM20 bar feeding system. Although it is a small element, it has a decisive role in the kinematic stability of the group, because it keeps the keys in the correct seat and ensures that feed finger tube 1501602 can slide along the longitudinal grooves without loss of guidance, unwanted rotation or progressive backlash. In the automatic cycle of the multi spindle lathe, the feed tube receives the feeding command from the cam and transfers the pushing force to the bar; if key fixing is not stable, the whole system may generate vibration, lateral displacement, irregular seat wear, feed errors and loss of repeatability against the bar stop. Screw 1501611 therefore contributes to continuity of the mechanical constraint between ring, key and longitudinal grooves, preserving the geometry of the assembly even during repeated cycles. In the version for bars up to 25 mm, recommended for light machining in the 20 to 25 mm range, correct tightening is particularly important to prevent dynamic stresses from causing loosening or undesired micro movements. The screw works directly with the key, the ring and nut 1501605, which laterally fixes the ring and connects the feed finger tube to the bar clamping feed tube through an external thread, allowing rotation to be transmitted to the assembly. During preventive and corrective maintenance it is advisable to check the head, drive recess, thread, contact surface, tightening condition, any signs of loosening and the condition of the seat on the ring. A damaged screw, an incorrectly tightened screw or a non suitable replacement can compromise feed tube guidance, increase backlash, generate mechanical noise and influence the dimensional quality of turned parts. This spare part is intended for technicians and maintenance departments that need to guarantee reliability of the sliding system and production continuity on the GM20.