How does the number of turns in a spiral ring affect its thrust capacity?

Multi-turn spiral retaining rings (typically 2-turn or 3-turn) provide significantly higher thrust capacity than single-turn stamped rings because the axial load is distributed across multiple thicknesses of material. The ring shear capacity is $P_r = _x000c_rac{ ext{π} imes D imes t imes n imes S_s}{KFS}$, where $n$ is the number of turns and $t$ is the thickness of one turn. Because they are coiled from flat wire, they have a $360^{\circ}$ retaining surface with no lugs, which eliminates the 'gap' found in stamped rings. This uniform contact ensures that the axial load is applied evenly to the groove wall, reducing localized stress concentrations.