Official Answer
Answer
Wave springs expand radially as they are compressed from their free height to their work height. This expansion is defined by the formula $\Delta D \approx 0.02 \cdot \frac{(L_f - L_w) \cdot t}{N}$, where $L_f$ is the free height and $L_w$ is the work height. If the spring is installed in a bore with insufficient clearance, the outside diameter (OD) will bind against the housing walls. This binding creates excessive friction, which manifests as a higher-than-calculated spring rate and causes localized wear or 'fretting'. For a Crest-to-Crest spring, it is vital to calculate the maximum OD at the solid height $H_s$ to ensure it remains below the minimum bore diameter $D_b$ throughout the entire operating range.
