These bearings have a contact angle, making them suitable for withstanding axial loads in one direction or combined loads. Structurally, after bearing radial loads, axial separation occurs. Therefore, using 2 bearings in opposition, or more than two in paired tandem is common. Single row angular contact ball bearings can employ preloading methods to enhance rigidity, making them suitable for high-precision rotating applications like machine tool spindles. Generally, angular contact ball bearings with a contact angle of 30° (code A) and 40° (code B) use cages. However, depending on different conditions, synthetic resin cages or polyamide molded cages are also used.