Official Answer
Answer
One of the primary marketing advantages of spiral retaining rings is the ability to install them without specialized pliers. For 'no-tool' installation, the ring is started into the groove by hand and then 'wound' in. However, for high-volume production, a tapered mandrel (for external rings) or a tapered sleeve (for internal rings) is used. The mandrel should have a smooth, hardened surface ($R_c 50-55$) and a taper angle of no more than $10^°$. A plunger then pushes the ring over the mandrel, expanding (or contracting) it just enough to slide into the groove. It is vital that the tool does not over-stress the ring; the expansion should never exceed 1% of the ring's diameter to prevent permanent deformation.
