Nearly five years ago I posted about building one of these. Well after 3 years of getting around to and 2 years in Atlanta it finally made it to the the top of my projects list. I kept it simple and cheap using a couple of 20" box fans I had on hand, 24"x24" pleated filters, some window screen for the pre-filter, a 1/4 sheet of hardboard for the baffle and a 1/4 sheet of pegboard for the top. I had a bunch of surplus IKEA phenolic back splash panels to enclose the sides of the frame. Originally I tried enclosing the bottom, using no filters and connecting a 4" hose from my 2hp duct collector thinking the fans would pull the dust in from the surface and the dust collector would pull the dust from the cabinet. It didn't work. Too much turbulence and static pressure such that there was very little suction above the fans and in some places reverse airflow. The fun part was perforating the top which I did last with the fans running. After a couple hours I had punched the required 946 3/4" holes with my big plunge router. This brought it to just under 50% open. The table did a pretty good job of eating it's own dust but the 3hp router's dust velocity is too much for it. The table is a secondary system meant to pull off and filter what the the Fein vac hooked to my sanders misses. Hopefully I'll be able to continue working with the tropicals and walnut I love but have become sensitized to without wearing a respirator. Time and my sinuses will tell. Sadly there was some collateral damage. When flattening the support grid for the top a shallow screw became a 'shiner' and deeply gouged the bottom of my prized Lie Nielson #4 bench plane. Made me a bit sick to f' up my plane. A couple hours of lapping the sole and grinding & honing a new bevel on the iron will set it right but that's not much of a consolation for shortening an heirloom quality tool's life by 25 or 30 years.