HFDC Dust Collector Optimization #2: HFDC Dust Collector Optimization - Cutting the TOP HAT pieces

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Blog entry by Morton WoodWorks posted 08-20-2014 07:56 AM 1716 reads 0 times favorited 1 comment Add to Favorites Watch
« Part 1: HF-DC Dust Collector Optimization Part 2 of HFDC Dust Collector Optimization series Part 3: ASSEMBLY, Installation & 1st Use »

After a couple days away from the shop I was able to get back at it after work yesterday. Crazy but I am the most productive at 4:30 AM when I get home from my 12hr shift. Today when I started I had no idea how far I would get, but everything went very quickly. First off, I went to my scrap pile and found a sheet of 3/4” plywood for the main components and cut it into 4 – 2’ x 2’ pieces.

After that I created a jig so that I could cut the circles on my table saw. This is something that I have seen before online but I have never tried before. If you are not very comfortable with your saw, please do not do this (I am not responsible for anyone getting hurt after trying this).

After I found center of all of the pieces and created the jig, I drilled a hole in the center that is the same size as the pin that I created in my jig. Then I cut the pieces making sure to leave one 1/4 of the circle for the inlet making what I would describe as a ‘tear drop’ shape.

After I had take all 4 2’ square pieces and created the tear drops I made one more from a scrap of 1/8” hardboard that I had laying around the shop. This piece will be the actual drop plate that allows the dust/debris through. Many posts suggest to use the thinnest material that will still be rigid to decrease the downward distance the air has to fall into the separator. As you can see, the jig that I used to cut the pieces has continued to be used for the centering pin while I did all of the layout work on the panel.

Like Thien suggested, I made the drop slot 1-1/4” wide and running a perimeter of 240* around the circle. The drop slot ended just to the side of my inlet in order to maintain optimum air flow. If you need assistance on dividing a circle without a protractor, there is a very simple tutorial that I found. I will try to explain, but it will likely be best to watch their video.

From the center of your circle, draw a line to the edge (the radius). Now put a mark on that line directly in the middle (1/2 of the radius). Next place a square on the radius line at the midpoint and mark the spot that the square intersects the circle both above and below the line. Then simply connect the intersection points with the center point and continue the radius line to the other side (essentially diving the circle in half). Then, erase the radius line that you used to find the 1/2 points and your circle is perfectly divided.

Or you can simply follow this link.

Since the 1/8” hardboard isn’t strong enough to support on its own and I don’t want to have any interference on the top side of the drop, I cut the bottom piece which I will call the baffle support very similar. It has the same 1-1/4” drop slot to mimic the hardboard piece, but it also has an additional 2” drop that runs about 1-1/4” past the hardboard drop slot. Once again, the centering pin made this process very simple to layout. One thing I almost forgot to mention…. on the end of the baffle drop closest to the inlet, you need to back miter the end so it forces the air down into the barrel.

Here is the finished product for today. Again, I have used the centering/alignment pin to ensure everything is lined up correctly. After final fitup, the drop slot is about 1/8” inset from the top ring on the barrel so that there is no chance for material to buildup on the top of the barrel ring.

Finally, you can see the plan that I have adapted this from with the current progress marked out. Hope to get more done in the coming days but I am struggling to conjure up some material for the walls of the baffle. I would really like them to be clear, but I don’t think I have anything in my garage. Anyone have any DIY ideas?


1 comment so far

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19657 posts in 2821 days

#1 posted 08-20-2014 10:45 AM

Progressing along nicely.

Clear walls…. um…. plexiglass???

I used a sheet if aluminum, that I had lying around.
Of course the aluminum is NOT clear.
Perhaps in the future, think “StarTrek the Movie”, aluminum will be clear!!!

-- Randy-- I may not be good...but I am slow! If good things come to those who wait.... Why is procrastination a bad thing?

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