On Sun, 26 Feb 2006 16:49:54 -0000, Jeff Dantzler
wrote:

[...snip...]

My main question is can any one tell me the thread spec for these
holes? Secondary to that, if any one has done this before (I know
folks have since I humbly admit to not coming up with the idea on
my own) would you have any suggestions on implementation?

[...snip...]

I just picked up a copy of Sandor Nagyszalanczy's book "Woodshop Dust
Control". There on page 177 it had a picture similar to what you are
talking about, specifically for contractor table saws. He does
describe in a couple of paragraphs just what he did, but there is only
1 photo from the top and you can't see how it is mounted. Anyway, it
might be worth a gander at your local library.