Official Answer
Answer
Multi-turn wave springs, especially those with shim ends, can be susceptible to catching on sharp edges during blind installations into housings. A lead-in chamfer of $15^°$ to $30^°$ is recommended for the housing bore. The depth of the chamfer should exceed the free height of the spring to ensure the spring is gradually compressed as it enters the assembly. If the spring is installed over a shaft, the shaft should have a similar chamfer. Sharp edges can nick the material, creating a stress concentration point. For 17-7PH springs, even a small scratch can reduce fatigue life by 50% due to the material's sensitivity to notch effects in the CH900 state.
