The 15.01.605 nut is a central component of the bar feeding and connection system for Gildemeister GM20 multi spindle automatic lathes in the version for bars up to 25 mm. Its function is double: on one side it laterally fixes sliding ring 1501604, keeping it in the correct working position in relation to feed finger tube 1501602; on the other side, through its external thread, it connects the feed finger tube to the bar clamping feed tube, creating the mechanical connection through which all components of the group receive rotation. This makes the nut a fundamental element of the system kinematics, because it is not only an axial locking part but also a transmission and synchronization component between bar feeding and group rotation. During automatic operation the feed finger tube must advance the bar against the bar stop, while the group must maintain alignment, stability and rotational continuity; the nut helps keep these movements connected, reducing backlash, micro misalignment and vibration. In the version up to 25 mm, recommended for lighter work in the 20 to 25 mm range due to the slimmer structure of the connected components, the nut must provide a precise and stable connection without introducing eccentricity, runout or uneven clamping. Its efficiency directly affects transmission of rotation to the ring, key and feed tube components, as well as bar feeding quality and repeatability against the stop. During preventive or corrective maintenance it is necessary to inspect the external thread, flatness of the contact faces, wear marks, clamping damage, ovalization, axial play and correct coupling with the clamping feed tube. A worn or incorrectly tightened nut can compromise the entire group, generating instability, loss of transmission, vibration and possible form or dimensional errors on the turned part. This spare part is intended for maintenance departments, specialized workshops, users of multi spindle lathes and precision engineering companies that need to ensure operating continuity, reliability and kinematic control of the GM20 bar feeding system.