Official Answer
Answer
A chamfer on the edge of the groove reduces the effective contact area between the ring and the groove wall. This increases the bearing stress on the remaining contact surface. If the chamfer is too large, it acts as a 'wedge,' converting the axial thrust load into a radial component that encourages the ring to 'dish' and pop out of the groove. Standard engineering practice limits the groove chamfer to a maximum of 5% of the ring's radial wall. If a larger chamfer is required for manufacturing or assembly reasons, the thrust capacity must be derated using a correction factor $C_{chaf} = _x000c_rac{d_{actual} - chamfer}{d_{actual}}$.
