This adapter sleeve mounts a bearing with a tapered bore onto a cylindrical shaft, converting the shaft seat into the taper required by the bearing bore. It has a bore diameter of 50.0 mm and a net mass of 318.87 g, built to standard design without any additional locking or sealing elements included in this specific mass value. The sleeve is fitted together with a locknut and lock washer to draw the bearing onto its tapered seat, generating the correct interference fit and internal clearance during mounting. This mechanical fixing method allows the bearing to be positioned at any point along the shaft length, simplifying assembly and dismounting compared with a directly tapered shaft, and is suited for applications where shaft tolerances are kept to standard cylindrical dimensions rather than machined tapers.