Internal Thien Baffle for HF DC - Tutorial

Darren Wright

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First I removed the cyclone tube from the DC
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I then cut a 20" square piece of 1/2" MDF and drew two lines corner to corner to get my center point. I then rough cut a 19" circle from it. The interior diameter was 18 7/8" for the cyclone.
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I mounted a 1/4" bolt in the T track of my router table at 9 7/16".
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Drilled a 1/4" hole 3/8" deep in the circle for a pivot point.
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I bored a 3/4" hole through a 1/2" piece of scrap as a spacer.
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I mounted a 1/4" sprial up-cut bit in my router, this allowed me to start the router and lower the mdf into the blade to trim up the circle.
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Using my original layout marks for reference, I marked out a 120 degree area.
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I then drew a layout 1 1/4" smaller in diameter for the remaining 240 degrees, and rough cut the section out.
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I moved my 1/4" bolt 1 1/4" closer to the router bit and trimmed up the circumference of the smaller radius.
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Darren Wright

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I wanted to use 3 screws to retain the baffle in the cyclone, so I made another mark 120 degrees off of my original 120 degree section. At 5 1/5" from the center I made marks on the 120 degree lines for my screw holes.
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I made a mark 1" from where the transition of the smaller radius goes to the larger one. This mark will be used to position the baffle. The mark is lined up with the inlet from the motor/impeller.
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I used my wixey to get the angle of the cyclone's internal cone, which was 30 degrees.
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Lining up the baffle, I drilled a 1/8" hole through my mounting hole all the way through the cyclones cone, repeat for each of the mounting holes.
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I then layed reference board across the cone to get the distance from the bottom of the cone to the holes (1/2").
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I wanted my baffle to be flush with the bottom of the cyclone, so I laid the baffle on the bottom side of the internal cone and used a reference stick laying across the bottom of the cyclone to get the height difference from the cone bottom to the bottom of the cyclone taking the thickness of the baffle into account. Distance was 4 1/4".
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I cut some 1" dowels 6" long and drilled 3/32" holes in the centers at each end 1 1/2" deep. These were then cut at 30 degrees at 4 3/4" from center to center (4 1/4" + 1/2"). (sorry, forgot the cut dowel pics)
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Using 1 5/8" course drywall screws I mounted each of the dowels to the baffle, but not tight, then aligned the dowels to the holes in the cone. I used fender washers with the screws on the cone side as it's not very thick metal. I tightened all screws once all the dowels were aligned.

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Darren Wright

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Staff member
Messages
16,028
Location
Kansas City, Missouri
That's it, reinstall the cyclone unit to the DC stand and connect it's hose.
2013-04-20 20.39.24.jpg

Prior I had a mini tornado of dust about the height of the clear bag, now there's just a small amount of movement in the bottom of the bag, but still see the dust dropping from the baffle to the bottom.
 
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