Answer
Multi-turn spiral retaining rings (unlike stamped circlips with eyelets) are wound from flat wire and lack installation holes, requiring unique assembly techniques.
Manual Installation:
1. Insert one end of the spiral ring into the groove.
2. Wind the remaining turns into the groove with a spiral motion (similar to winding a key onto a ring).
3. Avoid using sharp screwdrivers that can scratch the shaft surface, initiating micro-stress risers.
Automated / High-Volume Tooling:
1. Use a tapered mandrel (for shafts) or a tapered sleeve (for housings).
2. A pneumatic plunger pushes the spiral ring over the mandrel, expanding it uniformly within elastic limits so it slips onto the shaft and snaps cleanly into the groove.
3. Scratch Prevention: Apply a light dry-film lubricant to the mandrel and ensure the mating chamfer on the tool has a highly polished surface finish ($R_a < 0.4 \mu m$) to prevent micro-abrasion of the shaft or ring plating.
