HFDC with Phil Thien Baffle

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Project by arw01 posted 07-12-2008 06:31 AM 27553 views 18 times favorited 13 comments Add to Favorites Watch

Phil Thien has made a remarkable discovery of a simple shape that helps separate the waste stream and keep more out of your filter. I am hoping I can avoid, or at last prolong my filter looking like the third photo there longer with the baffle installed.

I made this after a thread on woodnet peaked my interest.

Another benefit is the material is not swirling around in the bag, so the noise the collector makes is substantially less as well. Enough so that I can hear my radio playing over the dust collector now.

-- No good deed goes unpunished!

13 comments so far

View Yettiman's profile


163 posts in 3764 days

#1 posted 07-12-2008 11:09 AM

Many thanks for posting. It’s not too clear from the photos what the principles behind the shape are.

Do you know how it works? Would love to know more, I am always looking to learn.

Great photos,

-- Keep your tools sharp, your mind sharper and the coffee hot

View Lee A. Jesberger's profile

Lee A. Jesberger

6859 posts in 4006 days

#2 posted 07-12-2008 03:41 PM

Hi ALan;

Honestly, I don’t know what this is for, but it does look good!


-- by Lee A. Jesberger

View John Gray's profile

John Gray

2370 posts in 3911 days

#3 posted 07-12-2008 04:05 PM

Explanation please?

-- Only the Shadow knows....................

View Ben Griffith's profile

Ben Griffith

50 posts in 3705 days

#4 posted 07-12-2008 05:06 PM

I had never heard of it before either, but I found this link:

Phil Thien cyclone separator lid design

Looks pretty interesting. I may give it a try sometime.

View arw01's profile


55 posts in 3640 days

#5 posted 07-12-2008 05:34 PM

Phil Thien has a website that details his journey and why he built it at:

In EXTREME summary, Phil was trying to keep the filter of his shop vac from plugging so much and was not happy with the results from commercial pre-separator rings.

Through some experimentation of his own, he came across this design here and found it very effective at separating a large amount of the dust and the heavy solids into his dust bucket instead of into the shop vac and therefore into his filter.

A few fellow woodworkers have reported significant reduction in noise, and dust reaching their cartridge filters on single stage dust collectors, so I thought I would give it a whirl!


-- No good deed goes unpunished!

View Blake's profile


3443 posts in 3900 days

#6 posted 07-12-2008 06:09 PM

arw01: where did you find that? What’s the website? The other link above didn’t really lead to anything I could get info from. I’d like to find more information on this.

-- Happy woodworking!

View joey's profile


396 posts in 3930 days

#7 posted 07-12-2008 08:20 PM

View Dusty56's profile


11819 posts in 3714 days

#8 posted 07-12-2008 09:04 PM

I see you have a Rikon disc / belt sander….I do also , any problems with yours ? I can’t keep the work ledge at 90 degrees to the belt when in the upright position and the speed at which my disc spins is more suited to a hi speed grinder than a sander….oh and the whole thing vibrates like crazy…I had to bolt it ( tried clamps first ) to my bench to keep it from walking off by itself. : (

So this project that you just made , have you noticed any less dust getting to your filter yet ? I had bought one of those cyclone seperators from WoodCraft and it does remove most of the chips etc., from the stream but of course the dust goes right thru it to the filter . I have the JET DC with the BULLDOG cartridge filter which I love more than the old bag system that I used to have ….. but I dread cleaning it .. LOL

-- I'm absolutely positive that I couldn't be more uncertain!

View arw01's profile


55 posts in 3640 days

#9 posted 07-12-2008 09:52 PM


It’s just in last night and I’ve not made any cuts or cleaned up any saw dust yet. Later today I have to make a couple sets of 1/4” or 3/16” strips for plywood edging that will run through the drum sander. It won’t make much dust though.

Just the noise reduction makes it worth while so far.

My Rikon belt table has to be shimmed to be at 90, and Rikon hasn’t done SH*T about it either. They said we are working on it for 5 months. I also have their bandsaw and don’t plan to buy any more Rikon tools.

My disc sander does not have any issues with vibration and I don’t mind the speed of the disk, makes it sand quicker.


-- No good deed goes unpunished!

View joey's profile


396 posts in 3930 days

#10 posted 07-13-2008 06:14 PM

this fellow has been writing about the one he’s building in his blog if you want to check it out. he build his in a 5 gallon bucket, sounds pretty interesting

I watched the video from the first link I put up and if preforms like that all the time this is a winning design in my opinion, this guy really has some here.

-- Joey~~Sabina, Ohio

View arw01's profile


55 posts in 3640 days

#11 posted 07-19-2008 04:30 PM

I pulled my bag off to check on a one week update, and to install a rubber cork to push the disc hard to the side so that it was firm around the edge.

The blue tape only held in one location, and the prior photo of a cork holding the baffle tight made me decide to take a look after a week.

Orientation of the baffle, and the three tape pieces

What they top of the baffle looked like, NO dust or pieces just sitting there.

How the filter looks, I’ve not done a LOT of sanding in the last week, but that looks encouraging!

I disturbed the bag removing it, but there was a nice fine pile of sanding dust on the top, so most of it ended up in the bad rather than in my filter it appeared.

I whacked the filter a couple of times and reached up and flicked the pleats. That is what feel out. Normally I get clouds and clouds and tons of crap coming out of there.

I will update again in a couple of weeks.


-- No good deed goes unpunished!

View Pete Jansen's profile

Pete Jansen

250 posts in 2947 days

#12 posted 02-04-2012 10:01 PM

I love my Thien converted HF dust collector. It collects all the dust and chips
and exhaust outside my shop. I got my plans from here if anybody is interested:

-- Lovin' sawdust in beautiful Fort Collins, Colorado

View williammartin's profile


1 post in 114 days

#13 posted 02-27-2018 08:56 PM

Thanks everyone! What type of material is best for the baffle? And the best way to connect the baffle? I have seen 2 methods: 1) one with large dowel rods and 2) the the other with metal clamps. Any suggestions?

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