Double-direction thrust angular contact ball bearings are designed for bi-directional axial positioning of spindles. These bearings are combined with cylindrical roller bearings of the NN 30 K or N 10 K series and mounted in the same bearing housing bore. This bearing combination simplifies the machining of the bearing housing bore. The nominal inner and outer diameters of the double-direction thrust angular contact ball bearings are the same as those of the corresponding cylindrical roller bearings. However, by combining the outer diameter tolerance of the seat ring with the recommended bore diameter and form and position tolerances for ultra-precision cylindrical roller bearings (standard bearing housing tolerances), an appropriate radial clearance is provided in the bearing housing bore. If the outer ring is not axially clamped in the bearing housing, this clearance is sufficient to prevent the thrust bearing from being subjected to radial loads.