Disc stack assembly having a clamp plate and a retaining ring to clamp a disc to a spindle motor hub

A disc stack assembly for use in a disc drive. A spindle motor hub includes an annular ring recess. A disc is clamped to the spindle motor hub by a disc clamp assembly comprising a clamp plate and a retaining ring. The clamp plate includes an inner ring engagement portion, an outer disc engagement portion, and an initial, substantially planar shape in an undeformed state. The retaining ring is secured within the annular ring recess and maintains the clamp plate in a conically deformed state so that the inner ring engagement portion of the clamp plate applies a first moment force against the retaining ring while the outer disc engagement portion of the clamp plate applies a second moment force as an axially directed clamping force upon the disc.