DerbyDad03 wrote:
I just bought a Harbor Freight 10" Disc Sander.

If I place a straight edge across the face of the disc, it's not flat.
It is "higher" in the center of the disc, i.e. the straight edge rocks
from side to side. With the straight edge held flat against the one
side of the face, there's about a 1/16"gap at the opposite edge of the
disc.

I'm new to disc sanders, so I'm not sure if this is an issue or not.

Thanks for your comments on this situation.

It's called a beveled disk.

If you think on it, you'll see that the center of a rotating disk moves much
less abrasive against the work than the outer edges. The beveled edge evens
out the contact. If you push a piece of work against the entire surface, the
parts of the work in contact with the outer edges of the disk will have more
material removed than the center.

Also a beveled disk allows you to use a disk sander as a joiner.