Another HF Dust Collector / Thien Baffle build

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Forum topic by tengallonhat posted 09-06-2013 09:39 PM 16439 views 12 times favorited 5 replies Add to Favorites Watch
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79 posts in 1952 days

09-06-2013 09:39 PM

Topic tags/keywords: resource jig trick dust thien baffle collector

I recently got fed up enough with all the dust in my garage to start to get serious about dust collection. I basically copied another Lumberjock post from Cory
Click for details

I never even turned the collector on when I got it. I decide after lots of reading to go the HF route and modify it to avoid disappointment.
First I assembled the base.

On the top piece of the base I braced the plywood with some 2×6 – to hold the lag screws in place for the mounting bracket.

Then I flipped the whole base on it’s back to attach the dust collector mounting bracket and motor.

With it still laying on it’s back, I decided now was a good time to cut the crosshairs off of the intake. There really is no reason to have these here with a Thien baffle pre-seperator.

I really wanted to save on vertical space, so in order to keep the whole collector low I decided to sink the garbage can into the base. I cut a hole in the base and attached a sub floor to the bottom of the 2×4s that make up the base.

Here it is upright, with the can and the Woodcraft seperator lid (more on this later).

Partly assembled, waiting for the Wynn 35a filter to arrive.

Because of the height of the Woodcraft separator lid ports, I ended up moving the whole motor mount up to the very top of the back piece in order to attach the flexible hose. (This added quite a bit of re-work to the project, especially considering when it was all hooked up I realized the Woodcraft separator lid was worthless!!!).

Like I said, I probably wasted 2-3 hours fitting things to use the Woodcraft Separator lid only to get all the way through the build to realize that the lid didn’t separate anything at all. This might be a result of the size of the can, the increased airflow with the Wynn filter, or the lid just being a bad product. Either way, I was planning on building a thien baffle someday so I just scrapped the woodcraft lid (going to take it back for a full refund thanks to the 90-day guarantee) and got started on the Thien baffle right away.

I still have a 4” flexible hose I am using to connect to my tools, but I wanted the seperator to be a bit more future proof with 5” ports. Using the lid that the can originally came with and a right and left cutting snips, I was able to cut out 5” port holes pretty quickly and get the the elbow and the outtake port fitted.

Next was cutting out the baffle bottom. To cut the outer radius, I rough cut the outer circle with a jigsaw, and then used my crosscut sled and a screw to make a simple circle cutting jig for my table saw.

Rough cut:

A few times around on the table saw (ignore the pencil marks, my compass was even more crude then my circle cutting jig!):

After figuring out the 240 degree slice, I used my square set to 1.25” (I think), and a pencil to run around the edge from the start to the finish of the 240 slice.

Finally, I just cut this slice with my jigsaw.

It’s not as precise as a router with a circle cutting jig, but it’s still plenty precise, made use of the tools I already have and the Baflle works wonders as is.

I for some reason forget to take pictures during the “sealing” and “attaching” steps. I sealed the ports top and bottom with hot glue and HVAC tape.
Using a forstener bit, I countersunk the dowels into base about 1/2” and set them in place with lots of glue. The holes are evenly spaced a few inches (4 or 5) off center in a way that doesn’t interfere with the ports as they line up to the baffle “slice”.

Once I got the dowels all in place, I set the top on the dowels and lined everything up. I traced from the bottom side around each dowel, removed the lid and drilled pilot holes from the bottom at the center of each dowel. Then I put the lid back on top and lined it all up again and set the lid in place with some drywall screws. It made the whole thing nice and sturdy.

Here is the final assembled dust collector, with the Wynn filter and all. Prior to having the Thien Baffle, using the woodcraft seperator lid, I cleaned out the bottom of my tablesaw and almost all the dust went right through into the bag! The trash can was close to empty and the bag had a few inches of dust in it. Since I replaced it with the Thien baffle, the dust no longer cyclones around in the bag and the trash can is filling while the bag remains at pre-Thien baffle levels.

After a few runs, I noted where there were dust leaks on the collector itself and sealed it all up with HVAC tape. I also added 3/4” weather stripping to the rim where the bag attaches. This eliminated virtually all of the leaks at the bottom bag.

Overall, I’m really happy with the end result.

In total it was probably about $350 with the filter and all the materials to build the base (a lot was from my scrap pile) and about 6 hours work.

5 replies so far

View DIYaholic's profile


19700 posts in 2872 days

#1 posted 09-07-2013 02:40 AM

Good job, tengallonhat!

I did a similar conversion to my HF DC,except I made a “Tophat” Thien separator.

Happy sawdust making!!!

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

View 47phord's profile


182 posts in 2434 days

#2 posted 09-08-2013 01:15 AM

Nice. I went the top hat route as well. I did a semi-scientific experiment to see how much dust I was catching, weighing a fixed amount of sawdust, sucking it up, and weighing how much was in the trashcan. It came out to around 90%; not bad, but it could be better.

View thelt's profile


665 posts in 3576 days

#3 posted 11-15-2013 01:06 PM

How do you determine the radius of the bottom circle and the distance from the top of the can?

-- When asked what I did to make life worthwhile in my lifetime....I can respond with a great deal of pride and satisfaction, "I served a career in the United States Navy."

View tengallonhat's profile


79 posts in 1952 days

#4 posted 11-15-2013 02:52 PM

I calculated the length of my support posts to start. Then I subtracted the distance from the top of the lid to where I thought the can/lid made contact (just a guess really). Then I measured down from the top of the can to that distance (plus the thickness of the bottom circle) to figure out my lowest point. Make a couple marks around the outside of the can at this point. It is a bit crude but close enough for this. Then take a string and run it around the outside of the can on your marks and pull it tight. You know have the rough circumference of your circle. From here figure out your radius. C = 2 x Pi x r. So divide the length of your string by (2xPi) to get your radius. Hope this helps.

View Garth's profile


16 posts in 2009 days

#5 posted 01-13-2014 09:11 PM

I like it. I hope to post my HF dust collector upgrade soon.

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