A disk mounting hub has a disk-mounting face formed at one end as a
truncated conical surface of revolution symmetric about a central axis. A
cylindrical inner hub member is coaxial with the hub body outside
diameter and the surrounding mounting face. The inner hub member is
adapted to receive a planar disk with a central opening. The mounting
face is disposed at a hub face angle (.pi./2+/-.OMEGA.) relative to the
central axis. Hub face angle .OMEGA. is selected so that a disk clamping
force F applied to an inner disk portion surrounding the opening bends a
portion of the disk interior to the hub inside diameter to conform with
the conical disk-mounting face. This interior bending portion reduces or
eliminates the tendency of the outer disk portion to form an excessive
conning angle .PHI..