Sunday, February 3, 2008

Home Built Cyclone for wood dust collection

Ok, this is the first posting here, lets see how this latest drip into the pool of Internet abuse goes.

Materials List
Cutting Section

This dust collection cyclone is a great fit for a small to medium shop, for light to even heavy use. Although, of course, the more you use it the more you are going to have to empty out the collection bin, and the filtration bag.

The cyclone can be powered by either a 1.5HP engine (generally for smaller shops) or a 2HP engine or higher for larger shops, depends on the distance that the chips have to travel. Links to recommended engines are in the materials section (

First, I'll post a link to where you can down the SketchUp model for the cyclone planes and a listing of the materials you'll need. Second, a break down on its construction. You need to cut a little slack in the construction department. I made this cyclone about 4 years ago after seeing a picture of one in an ad, and from the picture and a little imagination I came up with the drawings, then later on converted the drawings to a SketchUp model. It has been going strong ever since.

SketchUp model can be accessed from here.
SketchUp is required to view the complete plans. Google provides an evaluation copy of SketchUp for free, but be warned, it is addicting once you start using it, and the registered copy is not cheap. But on the lucky side I haven't seen an issue other than "EXPIRED" in the title bar.

Materials List (all materials are available from Lowes or Home Depot, except of course the engine):

1) 1.5HP or for medium sized shop a 2+HP Dust Collection engine (Grizzly 1028Z (1.5HP) or Grizzly 1029Z (2HP 220V) Dust Collector)
1) 1/2 roll of 20" Galvanized Steel Flashing, aluminum flashing really doesn't have the structural strength to hold up to the vacuum or to the flying wood chips
1) 3/4"x 4'x8' MDF
1) tube of silicone sealant
2) large handful of wide, but small aluminum rivets
14) 3/8" T-nuts
14) 3/8" washers
14) 3/8"x1 1/2" bolts
2) large handfuls of 3/8"or 1/2" machine screws, pan head type, do not use self tapping screws
1) small handful of 1/2" machine screws, flat head type
1) 2' section of 2"x4", for french cleat
1) 6" flange section of duct
1) 33 gal. trash can, with a linking lid
1) small handful of 3" drywall screws
1) large handful of 1 5/8" drywall screws

Cutting Section:

First start to work on one sheet of MDF. The first cut should be to divide it into half so you have 2 4'x4' pieces. (If your sheets are shy a little that's ok, the back is 21 1/2" so you can have one side shorter.) You then want to cut one of the 4'x4' sheets in half and half again, so you end up with 4 pieces that are 24"x24".

Start off by making the top and bottom platforms. Take two 24" pieces and stack them. Draw an X from corner to corner to find the center. Predrill and screw in 3 to 4 1-5/8" drywall screws a little shy of 3" from the center mark, and drill a small hole straight through both sheets on the center mark. Draw a line to divide (bisect) the 24" square into equal 12"x24" rectangles then, using a trammel or pencil on string, make a 24" arc rounding one of the 12"x24" rectangles leaving the square end alone. Using a band saw or jig saw cut the corners off on the measured arc.

Remove the screws holding the semi rounded 24" squares and measure a 3"radius (for a 6"hole) on one piece and a 10" radius (for an 20" hole) on the other, both from the center hole. Cut out both holes with a jig saw making starting holes with a drill first. Write a #1 on the one with the 6" hole and #2 on the one with the 20" hole. That is the way I will refer to them during the Assembly portion.

Just in case you are getting better the second time of cutting straight circles out of MDF, take a new piece of 24" square board and draw 3 circles from the center, one 6" wide (3" radius), one 19 7/8"(maybe closer to 19 15/16") wide (9 15/16" radius), and the last one 22" wide (11" radius). Again use a small to medium sized drill bit several times to make a starting point for the jig saw blade. You should end up with a 6" disc (which can be tossed), a circle just under 20" with a 6" hole in the middle (Refer. #3), and a 2" ring with an 20" I.D. (maybe a little more) and a 22" O.D. (Refer. #4).

The back is the simplest, a 24"x 21 1/2" rectangle (Refer. #5). The last piece of MDF (12"x20") that is to be cut doesn't need to be dealt with until the end (Refer. #6). But at this point you should have gone through about half a sheet of MDF.

Ok, it is steel cutting time. PLEASE BE EXTREMELY CAREFUL WHEN CUTTING THIS. USE GOOD LEATHER GLOVES AND SHARP TIN SNIPS. MARK EVERYTHING FIRST WITH A SHARPIE AND WHEN YOU ARE DONE CUTTING USE A FILE TO REMOVE BURRS AND SHARP EDGES, BUT ALWAYS USE GLOVES. Roll out the galvanized steel flashing and put it upside down so that it doesn't roll up on you. Measure out about 64" and roll it around the #3 piece of MDF. There should be enough to wrap around the piece with over an inch to spare, this will provide ample riveting area and sealant area. Set this aside in a safe spot away from people, animals, and other stupidity.

Next cut a cone shape out of the flashing. This is a lot trickery. The angle is about 155 degrees or 25 degrees off vertical. The sides should be about 18 1/2" on the angle, the bottom should be about 5 3/4" across (I'll explain why 5 3/4" and not 6" in the Assembly portion, and in the next paragraph), and the top of the cone should be about 21" (again see Assembly portion). The cone with the 5 3/4" hole should measure approximately 16 1/2" tall. Remember to leave about an inch extra when you mark the cone's side edge to allow adequate riveting and sealant room.

After the cone is cut out lay the sheet metal out on a workbench. Measure an arc 1" down from the top arc and another 1" up from the bottom arc with a Sharpie. Cut 1/2" to 1" wide tangs up to the Sharpie line. These tangs will allow the cone to be attached to both the 6" flange connector on the bottom and the 22" ring on top.

Now hopefully your fingers aren't sliced to ribbons and you were a good little woodworker and wore heavy gloves while working with the sheet metal. Now it is time for the assembly!

Assembly: Refer to SketchUp model for placement and visual aid in connecting parts.

First part is to attach piece #1 and piece #5 along the 24" sides. Use 1 5/8" drywall screws (at least 6) and yellow glue to attach the #1 to the top side of #5, don't forget to predrill the holes.

Take piece #3 and clamp it to the underside of piece #1 so the the two 6" hole are aligned. Drill 6 holes at equal angles and distance (preferably about 1" to 2" from the rim of the 20" disc) through both pieces #3 and #1. Set t-nuts into the holes in piece #1.

Take the 64"x20" piece of flashing and curve it in an approximate 20" cylinder and cut out an elongated tear drop shape to allow the 6"duct to enter into the finished cylinder. With a smaller tear drop shape you can always cut away more and reshape, so be conservative until the 20" cylinder is formed in the next step. The tear drop shape is so that when the 6" inlet duct is placed in it will follow the curved section in the back of the cylinder.

Take piece #3 and wrap the 64"x 20" flashing segment around it, clamps help. Drill holes in the flashing to accommodate the 1/2" machine screws, one about every 4" to 6" on both top and bottom. Attach the flashing to piece #3 adding one screw at a time and sealing with silicone sealant until the flashing is completely wrapped in a 20" cylinder.

Take piece #2 and work the 20" cylinder into the 20" hole, file if needed with a rasp, fill gaps and seal the rest of the cylinder against the piece #2 with silicone. Use 1/2" pan head screws to secure it in the MDF just like around #3.

Drill rivet holes through the overlap of the sheet metal about every 2" to 3" and use silicone to seal, then use rivets to help seal it off permanently. Then cut a section of 6" circular steel duct about 18" to 19" long. Drill at least 8 machine screw sized holes in the duct about 1/2" from one end. Screw and seal into the 6" hole in piece #3.

Cut another 20" section of the 6" duct and attempt to place it into the hole in the 20" cylinder created by the tear drop cut. Modify the tear drop opening to accommodate the inlet duct. Cut the inlet pipe leaving about 2" in the inside of the cylinder so tangs it can be cut to rivet and seal the inlet pipe to the cylinder.

Next attach the 20" cylinder section to pieces #1 and #5 with 6 1-1/2" long 3/8" bolts and washers, then screw in piece #2 to piece #5. And with that the top section is pretty much complete.

Form the cone using clamps to hold the shape. Drill holes for the rivets about every 2" to 3" and seal with silicone. Bend the tangs down on the large side of the cone and fit to piece #4, the 22" ring. Drill holes in the tangs, about every fourth tang will do, for flat head screws and seal with silicone. Align the cone and ring with the bottom of the main section and drill 8 3/8" holes, fit in t-nuts, and attach with 1-1/2" long 3/8" bolts and washers.

Drill rivet holes in the 6" flange connect and connect and seal to the now "bottom" (small hole) of the cone.

Attach a french cleat on to the back top of piece #5 with at least 10 screws, and a 2"x4" block to the bottom. Then you are set to attach to the wall.

Before placing the engine on top of the cyclone test that the cyclone will hold the weight and if all is good place the engine on top of the cyclone and attach the bag unit, the bottom 6" pipe, and trash can with a 6" hole. Seal up any leaks with silicone put make sure you can remove the pipe on the bottom of the cone to allow chip disposal.


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