|Project by awlee||posted 11-27-2013 01:36 PM||2637 views||28 times favorited||9 comments|
In an effort to capture all the dust that spews whenever I sand, I made a downdraft table. Besides gobbling dust, it had to meet some other requirements, including being light enough for me to lift easily onto my workbench, a large enough top to accommodate decently sized project pieces but not so large that my dust collector, at 650 CFM, couldn’t create enough suction, and an easily removable top.
Figure 1 shows the final table. The carcass is made of pine and the top of MDF. The rough dimensions of the carcass are 24” x 24” and about 4” deep, the top about an extra 1.5” all the way around. The dust port is 4” in diameter and can be hooked directly to a dust collection hose. I tried to find good advice about the hole patterns—how large, how many, how far apart—and there are many suggestions, though definitely no consensus. I settled on 3/4” holes, drilled in pairs, and spaced about 4” apart. Because the top is easily removable, I can quickly change it for a different top with different hole patterns. The table is light, most of the weight from the MDF top. All the surfaces are finished with Danish oil.
Here’s how I made it:
Figure 2 shows the pine box with angled supports for baffles. The baffles help the dust slide toward the center suction hole and also cut down on the interior area and, one hopes, make the suction more powerful and efficient.
Figure 3 shows the simple joinery and also the dowels I inserted in each of the corners to accept the MDF top.
Figure 4 shows the bottom panel, which is just a 1/4” scrap plywood that has been inserted into grooves. I didn’t glue the bottom panel; it just floats.
Figure 5 shows the baffles in place and two oak strips that stretch across the box to help support the top. The top just sits on the box—no other attachment than fitted loosely onto the dowels.
Figure 6 shows some stops I made to help hold the project pieces in place.
I’ve sanded on the downdraft table several times now, and I must say that the results are just okay. The suction isn’t nearly as powerful as I’d hoped. I definitely do not capture all of the dust. I’ve been resisting investing in a more efficient system—something like a Festool sander and dust collector—but, for health’s sake, may need to think more seriously about that. I’d certainly appreciate any wisdom from the Lumberjocks group about any aspect of the table, whether I should try a different hole pattern, more powerful dust collector, smaller box, maybe even a different way to capture dust altogether.