Official Answer
Answer
The K-factor is a safety coefficient used in the thrust load capacity formula $P_a = \frac{D \pi S_y t}{K}$ to account for the non-ideal distribution of stress. In spiral rings, the load is not always perfectly axial due to the 'gap' and the multi-turn geometry. A K-value of 3.0 is typically applied for calculated thrust loads to provide a margin against dynamic loading, shock, and variation in groove depth. For critical safety components, finite element analysis (FEA) is often used to refine the K-factor by simulating the actual contact pressure and the 'prying' effect that occurs at the ring tips.
