A stacker reclaimer is a large and efficient machine used for bulk material handling in stockyards. It can stack and reclaim materials such as coal, iron ore, limestone, and other minerals. A stacker reclaimer consists of several components, such as a bucket wheel, a tripper conveyor, a boom conveyor, a substructure, and a slew drive. The slew drive is an important part of the stacker reclaimer, as it allows the machine to rotate and move the boom conveyor in different directions. The slew drive consists of a motor, a gearbox, a brake, and a pinion gear that engages with an external ring gear attached to the slewing bearing. The slewing bearing is a large and robust bearing that supports the weight and torque of the upper structure of the stacker reclaimer. The slewing bearing also enables the smooth and precise rotation of the machine. The slewing bearing is usually mounted between the substructure and the upper structure of the stacker reclaimer, and it can be either trolley type, slewing bearing type, or tapered roller type. The slewing bearing type is the most common one, as it is simple and convenient to install and maintain. The slewing bearing type also has the advantage of being able to withstand the overturning moment of the upper part.