"George" wrote: (clip) Reversing? makes no sense to a power sanding type
and on cross-grained bowls. Long-grained stuff would result in
cross-grain in either direction, (clip)
^^^^^^^^^^^^^^^^^^
When you sand, tiny fibres of the wood grain lie down and are not cut off.
When you reverse, these fibres are lifted, and at least partially removed.
I believe this works on both long-grain and cross-grain sanding.