A couple things. One, what kind of saw? I have a G1023 cabinet saw, nothing in the design to help with dust collection. I put a scrap of magnetic sign material over the 'smile' where the blade elevation mechanism moves and partially plugged the space between the cabinet and top with rolled up newspaper. I kept plugging until there was what I felt was reasonable air movement through the blade opening. You need a certain velocity to keep dust entrained in the air flow. A stock saw, either contractor or cabinet style won't produce that without a honkin' big dust collector and appropriate ducting, there's too many leaks. Plug some of the leaks and velocity should improve. You don't want to starve the system of air but that seems unlikely with a '2 h.p.' collector. It also seems easier to 'steer' the dust into the ducting while it's airborne. Once it settles it doesn't want to move. I also made the 4" dust collector hole into a 6" hole. This is with a '2 h.p.' Penn State collector w/ Thien baffle in the funnel.