The SC45.52.150 rod is a technical spare part for the finished-part ejection system of the hydraulic pick-up spindle installed on the Gildemeister-DMG Mori GM20AC automatic multi-spindle lathe. The component operates inside the spindle body and belongs to the auxiliary unloading kinematics of the machine, acting after machining and after the finished component has been taken over by the pick-up spindle. Its main function is to convert the axial thrust command into controlled ejection of the part from the pick-up spindle collet, while maintaining correct coaxial alignment with the spindle axis and allowing the assembly to rotate freely during the operating sequence. This configuration is critical because the pick-up spindle works in coordination with hydraulic collet opening and closing, the backward movement of the spindle and the position of the main spindle collets mounted in the spindle drum. The rod runs through the entire internal length of the pick-up spindle, must slide without sticking and must allow free rotation without abnormal friction, vibration, interference or misalignment that could affect part ejection and the continuity of the automatic cycle. A dedicated ejector head is mounted on the front end of the rod and is manufactured according to the geometry of the part being produced, the available contact area, the residual part length and the need to protect machined surfaces, threads, grooves, ground diameters or delicate profiles. The head is therefore not a universal element, but a functional interface between the rod and the machined component; for this reason the correct choice of rod and ejector head must be evaluated according to the machining cycle, material, required rigidity and final part position inside the pick-up spindle. The referenced versions have total lengths L= 770 mm, L= 800 mm and L= 830 mm. The correct length depends on the actual distance between the fully retracted pick-up spindle and the collet of the main spindles located in the spindle drum, also considering part projection, collet gripping depth, available ejection stroke and the dimensions of the customized head. An incorrect length may reduce thrust efficiency, anticipate or delay contact with the part, generate end-of-stroke impacts or compromise the synchronization between pick-up, collet opening, ejection and unloading. From a kinematic point of view, this component does not transmit motion to front toolholder spindles and does not directly control radial or axial slides, but it interacts with the auxiliary pick-up spindle system and with the sequence of feed, retraction, free rotation, hydraulic collet opening, hydraulic collet closing and part ejection. Its stability affects cycle repeatability, unloading reliability and the reduction of machine stops caused by retained parts, incomplete ejection or uncontrolled contact. During preventive and extraordinary maintenance it is advisable to check straightness, condition of the sliding surfaces, internal spindle cleanliness, absence of burrs, wear on the thread or ejector-head mounting seat, freedom of rotation and absence of abnormal backlash. For machine tool builders, retrofit workshops, maintenance departments and production technicians, this rod is an essential functional spare part for keeping the GM20AC pick-up spindle group efficient, optimizing the unloading phase and ensuring production continuity in precision automatic machining.