Official Answer
Answer
Spiral retaining rings are produced by coiling flat wire, which means they do not have a 'stamped' edge with a burr like a circlip. However, the 'end' of the wire where it is cut can have a slight burr. In precision aerospace bearings, it is critical that this cut end does not face the moving parts. Furthermore, while the ring is generally flat, the coiling process can introduce a slight 'dish.' During assembly, the ring should be oriented so that the convex side faces the load, which helps to resist the 'dishing' effect under thrust. In high-vibration environments, the gap of the spiral ring should be oriented $180^\circ$ away from the primary vibration axis to minimize the risk of the ring 'walking' or rotating within the groove.
