6" Thein Dust Seperator works great

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Review by rawdawgs50 posted 12-13-2010 07:01 AM 15425 views 46 times favorited 23 comments Add to Favorites Watch
6" Thein Dust Seperator works great 6" Thein Dust Seperator works great 6" Thein Dust Seperator works great Click the pictures to enlarge them

This seperator works great and cost less than $40 if you have scrap MDF/ Laminate laying around.

See video of it in action on youtube

I wrote up a complete step by step process for building this seperator if anyone is interested

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23 comments so far

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Mark Shymanski

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#1 posted 12-13-2010 07:07 AM

Very interesting. Thanks for the links.

-- "Checking for square? What madness is this! The cabinet is square because I will it to be so!" Jeremy Greiner LJ Topic#20953 2011 Feb 2

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991 posts in 2648 days

#2 posted 12-13-2010 07:41 AM

I like this and its not bad, but…

I think the problem is you don’t have enough volume in the area where the dust falls out of the airstream into the collection bucket. As you said, the dust should not keep circulating, it should be able to fall into the collection bucket.

One way to help would be to extend the outtake down below the plate. Then the dust would be forced below the plate and fall out of the airstream. Just a thought. If you did just this, then more dust would build up above the second plate…

I have to think on this more…

-- "Find out what you cannot do and then go do it!"

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82 posts in 2052 days

#3 posted 12-13-2010 03:02 PM


Thanks for the comments, if you mean outtake as in the top outlet, extending it down past the bottom plate of the seperator would actually kill the tornadic action inside the seperator. It would then just pull all the dust into the dust collector because the force of suction is way to strong. I know this because my first attempt of building one of these was something like that, before I learned of the Thein design….and it was a huge failure.

This actually creates a small Tornado inside and causes centrifugal force to push the debris against the wall’s edge. The debris does all seem to drop after ‘X’ amount of rations, I am just unsure if I could have made it more efficient meaning less revolutions. That is what I am experimenting on now.

Either way, it is working, very well even with small dust. Heavier dust (planer/jointer) will absolutely be no problem.

At this point I do a good amount of wood working and emptying bags was not something I enjoyed to much. I am hoping that I will have to empty the bag at least 1/20 of the times less frequently. If thats the case, then this is on par with a dedicated Cyclone efficiency for 1/5 of the price.

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#4 posted 12-13-2010 04:42 PM

Great job and video, Thx for the post!

-- Ken, "Everyday above ground is a good day!"

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#5 posted 12-13-2010 05:00 PM

I’ve seen your writeup on Phil’s site. VERY interesting build. I really like my 5” side inlet, but I had never considered building a hat style separator. That is a great way to maximize the available volume in the dust bin.

EEngineer. The plate as you call it, or baffle as it is called by the guy that came up with the design, is supposed to be below the center tube. Phil has done a good bit of experimenting, including as you suggest. Google Thien Cyclone, and take a look at the forum there. There is a LOT of good information there.

-- My workshop blog can be found at

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#6 posted 12-13-2010 05:39 PM


There are more updates coming. I just have not had time to get them written. This thing really works well and has not contributed to much loss in static pressure, at least none that I have noticed. I already have a design for one from Lexan that will be much faster to build but at a slightly higher price. If there is enough interest in this build I will write a detail on that as well.

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661 posts in 2308 days

#7 posted 12-13-2010 07:46 PM

Thank you for posting this as well as the step-by-step on the link. I really, REALLY like this and will probably try one of my own. As you’ve already noted, I have plenty of scrap laying around and this would be very inexpensive.

But I do have one question. With the size of the opening through which the dust falls down into the can “so small” in width, are you having any issues with larger pieces of wood being sucked into the vac itself? I raise the question because of another post this past weekend in the forums from a LJ who unfortunately sustained impeller damage when his vac ingested a chunk of cutoff.

The narrowness of the slot you’ve cut would suggest that chunks are going to be forced further upstream into the vac itself, rather than cycloning out and down into the can.

Just wondering. Thanks again. Cheers!

-- Dave; Lansing, Kansas

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#8 posted 12-13-2010 09:42 PM

nice design on your build. I really should get to making one… keeping saying, never doing. thanks for yet another reminder!

-- ㊍ When in doubt - There is no doubt - Go the safer route.

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991 posts in 2648 days

#9 posted 12-14-2010 03:22 AM

Yah, I visited the Thien site and went through some of the material there. Fascinating…

I need another hobby like a hole in my head, but I think that this technique will be interesting to play with. I have been designing a workstation for my tablesaw for some time now and I want to incorporate a dust separator into it. It will have to be something like this rather than the taller cone-type designs I see here on LJ’s.

Nice job! Please be sure to post any improvements you make as time goes on.

-- "Find out what you cannot do and then go do it!"

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82 posts in 2052 days

#10 posted 12-14-2010 03:31 AM


The largest chunks of wood I suck up come from my Lathe, and none are really big just long shavings. All my heavy equipment I run decimates wood. I use zero clearance inserts where appropriate.

The only place I can think of where a chunk of wood would be is on the floor, and in my shop a broom and dustpan is what I use if its on the ground.

But to answer your question, the separator actually works better with larger particles of wood.


I will opt to not put in the posts and I will let you all know if it sags over time, but I don’t think it will. There is more than enough meat on the neck of the MDF.

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3229 posts in 2857 days

#11 posted 12-14-2010 05:17 AM

Great work on one of my favorite shop accessory , your video and how to build one should cause a surge on the site. I’ve had mine now for a year and absolutely love it. Enjoy your clean shop…BC

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#12 posted 12-14-2010 05:22 AM

Thanks for the writeup and information! Making one of these is definitely on my to-do list, if I can ever get around to making my DC setup permanent…

-- Optimists are usually disappointed. Pessimists are either right or pleasantly surprised. I tend to be a disappointed pessimist.

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1929 posts in 2805 days

#13 posted 12-14-2010 07:36 AM

I built one of the seperators just as shown on the Thein web site, and it has worked great. At first I thought it would catch the large pieces that came through, however I have found that I have actually been getting alot of the fine dust also, I am very pleased with the way it has worked.

-- Tom D

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507 posts in 2269 days

#14 posted 12-14-2010 04:20 PM

If I were building it this way (and I just might, a Thein has been on my todo list for a while), I would have bent the plywood around the other way, so that the kerf cuts were all on the outside edge. I think that would ensure you have a better surface on the inside for less turbulence overall and would make for an easier build.

Very nice write up though, I’ll definitely look to it for some inspiration when I finally get around to making one.

-- The difference between being defeated and admitting defeat is what makes all the difference in the world - Upton Sinclair, "The Jungle"

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82 posts in 2052 days

#15 posted 12-14-2010 06:21 PM


If you bend the plywood the other way, you will have nothing to bend. It will snap like a twig. Test it on a scrap piece to see what I am talking about. Plywood veener does not work well when compressed, but it is resilient when stretched like the way I did it.

Also of note, the joints where the laminate edges meet are negligible in causing any reduced amount of tornadic action. It could have been much worse, even overlapping (as long as the overlap was in the direction of flow) and it would still work fine.

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