Official Answer
Answer
'Groove Rolling' occurs when the thrust load causes the wall of the groove to deform plastically, creating a ramp that allows the retaining ring to slide out. This is highly dependent on the 'Squareness' of the retained part. If the face of the retained part is not square to the shaft axis, it applies a non-uniform load to the ring. This creates a tilting moment (torque) that concentrates the force on one edge of the groove. This localized stress exceeds the yield strength of the housing material much sooner than a uniform load would. Failure analysis typically shows a 'peeled' or 'flared' groove edge. Prevention involves ensuring the mating part's face is perpendicular within $0.002$ inches per inch of diameter.
