Explain 'Groove Fit' and its necessity for preventing axial play in precision assemblies.

'Groove Fit' refers to the axial clearance between the ring thickness $t$ and the groove width $w$. For zero-axial-play applications, a 'Balanced' or 'Light Press Fit' is desired. However, standard rings are designed with a 'Clearance Fit' (e.g., $w = 1.05t$) to allow for easy installation. If axial play must be eliminated, engineers specify a wave-shaped retaining ring (a 'WaveRing'), which combines the functions of a retaining ring and a wave spring. This allows the ring to take up the cumulative tolerances of the assembly, providing a constant axial preload of $P = k \cdot \delta$ where $\delta$ is the compressed distance.