Ring 5301346 is a component of the collet opening and closing group of the main bar spindle on the Gildemeister DMG Mori GM16AC automatic multi-spindle lathe. The image shows a robust annular part with a central through bore, frontal working surfaces and distributed contact lugs, designed to interface with elements that transmit thrust and reaction during the clamping cycle. Its main function is to act as a connecting joint between spring pack 5301350 and the sleeve carrying the collet closing levers, transferring the axial pressures generated by the closing system towards the bar drawbar group and the main spindle collet. The component works frontally on three contact points with the spring pack and on two frontal contact points with the sleeve, receiving load from both sides and helping distribute the force correctly during collet opening and closing. From a kinematic point of view, this ring is not a simple spacer: it is a force transmission element inside the clamping mechanism. It supports the action of the spring pack, keeps the functional reference between sleeve, closing levers and clamping noses, allows axial thrust to be converted into closing action on the bar collet and contributes to the stability of bar clamping in the main spindle. This function is essential to keep the bar correctly locked during spindle drum rotation, bar feeding, gripping, and during the action of radial, axial and frontal tools working on the part. A worn, deformed, cracked or broken ring can modify clamping repeatability, cause loss of accuracy on turned diameters, unstable material positioning, vibration, dimensional errors, rejected parts and consequential breakage of tools, bar collet and drawbar. Because it is exposed to alternating pressure, functional impacts and repeated opening and closing cycles, it must be considered a wear part subject to fatigue failure. For preventive maintenance on the GM16AC, keeping a minimum stock is recommended, especially in continuous production or on machines operating with high cycle rates. When replacement is due to normal wear, the same operation should also be evaluated on the other spindles, so that the clamping group keeps a uniform behaviour across all positions of the spindle drum. Replacing only one ring is normally suitable in the event of a collision, local breakage or isolated damage. The component should be checked whenever loss of part accuracy, dimensional variation, irregular collet closing, abnormal noise in the drawbar group, fatigue marks on the frontal surfaces or breakage of connected elements are detected. For maintenance technicians, machine tool users and multi-spindle lathe specialists, ring 5301346 is a critical spare part for production continuity, clamping mechanism reliability and protection of the complete bar, collet, drawbar, spring pack and lever clamping finger.