What are the design requirements for the pilot diameter when installing a wave spring on a shaft?

When a wave spring is installed on a shaft (ID piloted), the shaft diameter $D_s$ must be sized to account for the spring's ID contraction during compression. Although wave springs primarily expand at the OD, there is a minor geometric change at the ID. The recommended clearance is typically $0.005$ to $0.020$ inches depending on the spring size. If the shaft is too large, the spring will bind, causing a localized stress increase and preventing the spring from reaching its intended work height. The shaft should be polished to at least $32 \mu in$ Ra to minimize wear on the spring's inner edges during cycling.