Answer
The thrust capacity of a spiral retaining ring is usually limited by the strength of the groove material rather than the ring itself. The formula for the allowable thrust load $P_g$ based on groove yield is $P_g = _x000c_rac{D imes d imes au_y imes au imes ext{Safety Factor}}{K}$ where $D$ is the shaft/bore diameter, $d$ is the groove depth, and $\tau_y$ is the yield strength of the groove material. A common pitfall is ignoring the 'Edge Margin' (the distance from the groove to the end of the shaft). If the edge margin is less than $3 \times d$, the groove wall may shear or deform plastically. For high-strength applications, we use a safety factor of 2.0 and consider the localized bearing stress which is $S = _x000c_rac{P}{\pi D d}$.
