Introduction: High Efficiency Table Saw Dust Hood
I know a lot of shops fight the same constant battle that I do against dust. One of the biggest offenders in my shop is the table saw. This tool is used extensively every single day and as much as I like the table saw I have, the factory dust collection ports seem to be a bit of an afterthought in the design and leave a lot to be desired. Most moderately priced table saws I have owned and considered purchasing seem to have similar shortcomings in dust collection. My saw, in particular, has a plastic hood that rides over top of the riving knife that is supposed to keep dust from flying up and redirect it to the dust port under the blade. However, due to the open clearance needed for the tilt mechanism, it is wide open underneath and half the dust makes it into the dust collector basically by chance and the rest ends up in the air or on the floor. To make matters worse, it is only a 2 ½” port.
The solution I came up with is designed to extract a very high level of dust with rip cuts under 3” wide and 1” thick. In my shop, the vast majority of cuts are rips under 3” in ¾” material so it will not work well for cutting large plywood panels, wide boards, crosscuts or thick material. However, the hood is attached to the rip fence and simply slides out of the way, usually without having to be removed. The factory hood is simply tilted back down over the blade. If the hood does need to be removed it is a simple matter of loosening 2 threaded knobs. My saw is set up with a 2” wide x 3” tall rip fence with a 1 ½” x 1 ½” l shape rider made of ¾” plywood and a 1/8” angle aluminum face. The dimensions given are built around this so you may need to modify as necessary to fit your machine or needs.
Using the new hood has been a tremendous difference. With the factory set up I estimate 50% of the dust was being collected. With the new hood, I estimate conservatively 90% of the dust is being collected. There is a noticeable difference in the entire shop.
Far and away the most intricate part of the build is the clear acrylic face. The main face part and two tilting blade covers were cut from a single 18” x 24” sheet of ¼” thick acrylic. (fig 1) I made 2 of the tilting blade covers simply to have a spare because I can see this part potentially wearing out or getting damaged over time. The parts were cut with a CNC router set to a high travel speed and low RPM. However, this can certainly be cut with more traditional tools like a jig saw and a drill. I have attached a scalable drawing. (fig 2) I will also be happy to share the V-carve CAD drawing and .tap toolpath file. Just send me an email or ask in the comments section.
The acrylic needed to be bent at a 90ׄ° angle. It could also be glued together as 2 pieces but I prefer the cleaner method of bending the acrylic. (fig 3 & 4) I used a shop built acrylic bending jig. There are many tutorials on how to easily build one of these with a piece of resistance wire.
The wood pieces that need to be cut are fairly straightforward. I used ¾” red oak, but only because that is what I happen to have lying around. Any ¾” hardwood will work fine. (fig 5) Below is the list of finished material:
Top Board – 6” wide x 11 ¾” tall. Both sides cut on a 20° angle parallel to each other
Base board – 2” wide x 13” long
Back support – 2” wide x 2 ¼” long. One side cut on a 20° angle so the 2 ¼” side is the short side
Filler Post – 1” wide x 2 ¾” long. Cut across the 1” side at 20° angle so the 2 ¾” side is the short side.
Front connector – 2” wide section of 1 ½”x1 ½” right angle aluminum. I cut one of the legs down to 1” purely for aesthetics. It is not necessary. Drill 2 holes matching the two holes in the acrylic directly below the 4” hole.
With the basic pieces cut there is one other component that needs to be addressed before assembly begins. The acrylic blade flap (fig 6) will be held down with a thumb screw which will need a stable set of threads to screw into. To accommodate this, a 1” x 4” piece of the ¾” oak stock was used to provide a base for a threaded insert. (fig 7) After drilling and placing the threaded insert it was bolted to the bottom of the Top board out of the way of the blade. (fig 8).
Assembly of the basic structure starts with attaching the top board to the acrylic face with #6 x ¾” wood screws making sure the head of the screw is below the surface of the acrylic allowing the blade flap to rotate upward without obstruction. (fig 9)
The back support will need to be attached to the base board 2” from the end of the board with #6 1 ½” screws. This allows enough room on the base board for the rear mounting bolt and threaded knob. Then the base board assembly is attached to the acrylic face with #6 1 ½” screws in the back and #10 1 ¼” in the front making sure to place the right angle aluminum in front of the acrylic plate (fig 10)
The filler strip is then attached alongside the back support with #6 1 ½” screws. (fig 11)
The next step is to attach the dust port to the acrylic face. I used a round 4” flanged dust port found at any woodworking supply store. Hold the port in place and using the mounting holes in the dust port as a template drill through the acrylic. Using ¾” long machine screws with washers, lock washers and nuts, attach the dust port to the acrylic face. (fig 12)
To make the port channel on the fence side of the hood I elected to use a 20” slice of 14” wide light gauge galvanized metal roof flashing because it has about the right balance between malleability and rigidity. There needs to be a crease on about a 20° angle near one side. Using a sheet metal brake, I found it advantageous to crease it along the natural curl of the metal from the roll. (fig 13) This light sheet metal can also be creased by clamping 2 scrap boards together to sandwich the metal and then pressing the seam with a third board.
Using a pair of pliers, sheet metal pliers are ideal, flatten the crease back out of one end of the metal perpendicular to the seam at least an inch from the edge. (fig 14)
Mounting the sheet metal to the hood requires using some form of clamping strip. I used ¾”x1” strips of wood, but metal or aluminum bar stock would work well too. The lengths are 11 ¼” for the bottom, 11 7/8” for the top and 2 ¼” for the side cut on a 20° angle. (fig 15)
Place the sheet metal on the fence side of the hood so the crease in the metal meets the angle in the acrylic face below the dust port. Secure it with a few screws allowing the metal to extend beyond the edges of the hood. (fig 16)
Form the metal into a cone shape and mark where it meets the edges of the dust hood. (fig 17 & 18)
Once the metal has been trimmed with a pair of tin snips or shears and the edges filed, attach it to the dust hood using the clamping strips. (fig 19 & 20) A little silicone sealer along the edges of the metal and any other gaps will make a difference.
Attach the blade flap with a ¼” x 1” bolt secured with a lock nut through the front hole and a ¼” x 1” thumb screw in the rear hole tightening into the threaded insert. (fig 21)
To mount the hood on the fence, it was placed on the fence and marked for ¼” thumb screws. Once drilled, t-bolts were placed in the fence and tightened with threaded knobs. (fig 22 & 23)
A “Y” connector is used to split the dust collection between the factory port at the bottom and the new port on the dust collection hood. (fig 24 & 25)
The blade flap can be tilted up and out of the way to slide the fence by loosening the thumb screw. (fig 26)
Rod Gunter is Operations Manager at Gunter Building Solutions and has over 20 years of experience in the homebuilding and cabinetry industries. Rod has been responsible for building over 200 homes above the $500,000 price point. Rod has trained large groups including all the major home centers on selling skills, construction techniques and sustainable natural wood products. Rod resides with his family in Holly Springs, North Carolina. Gunter Building Solutions owns WoodAirGrille.com which produces wood return air filter grilles and wood return air vents.