On Fri, 05 Mar 2010 17:39:58 +0000, graham wrote:

When I mentioned the problem of flatness, I was thinking of the table as
a whole. The preferred method of construction seems to be a thick piece
or two of MDF with some kind of smooth surface layer laminated to it.

MDF will sag over time, but you can avoid that if you're willing to
remove the router when not using the table. Or build a torsion box and
use that for the table.

--
Intelligence is an experiment that failed - G. B. Shaw