Steve knight wrote:

12" is about the minimum you want on a disc sander. even then you only
get about 3 useful inches out of it unless your working on small
pieces.
you want to make sure the disc is not spinning faster then 1750rpms.


Amen.

Anything less than 12" dia is about as useless as breasts on a boar hog.

Been there.

BTW, IMHO, a good disc sander is just about the most useful tool I've
got when you do things like boat joinery.

Lew