Shop Made Jigs, Fixtures and Solutions #5: Thein Separator Epic FAIL!

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Blog entry by DaveTPilot posted 03-27-2012 03:23 PM 5362 reads 1 time favorited 4 comments Add to Favorites Watch
« Part 4: Shop Notes Drill Press Sharpening System Part 5 of Shop Made Jigs, Fixtures and Solutions series Part 6: Shop Made T-track »

I know this topic has been hashed and rehashed to death but I want to chronicle my progress in my journey to improve my dust collection system.

I was using this lid separator with really good results. I collected 100% of all chips and quite a bit of fine dust as well. The main problem is the efficiency diminished greatly once the can accumulated even a small amount of debris.

So, I thought I would try the Thien Separator. I did not want to invest a lot of time building the type seen in this video link so I went with the simple version as seen here.

With my dust collector, a 3hp KUFO, this was an abject failure. Not a single chip or piece of dust collected in the trash can. I am not exaggerating…100% or all the dust and chips went straight through my dust collector impeller and into the collection bags. (I made sure not to suck up anything too big so as to protect the impeller.)

In fairness, I believe this works very well with shop vacs and lessor collectors. The type seen in the video link above would probably work great with my system. I may build one when I have the time but for now I am trying something a little different. I am making a video as I go along and will share my experience along the way.

Stay tuned for the rest of the story.

I had some camera difficulties while chronicling my progress. Here is a short clip of the final test made with my iPhone. I was amazed by the results.

-- How valuable is time to a person who spends his disparaging the beliefs of others? --David Berthelette

4 comments so far

View Cory's profile


760 posts in 4869 days

#1 posted 03-27-2012 06:20 PM

Sorry to hear about your failure with the Thien lid. My experience was the opposite. I have almost 100% going into my separator. I have a 2hp HFDC. You can see my lid here:

Click for details: Harbor Freight Dust Collector Mod

Are you sure you had tight seals on the lid and constructed it correctly?

-- The secret to getting ahead is getting started.

View JollyGreen67's profile


1676 posts in 4213 days

#2 posted 03-27-2012 09:14 PM

I built a Thien for my 1HP HF, with the top being melamine, with a seal on the outer edge, to seal against the 30 gal trashcan. Works perfect. Whenever chips enter the system, which is a lot, I can hear them hitting the side of the can. NO chips, and very little dust reaches the bag. Happy, happy, happy. ;)

-- When I was a kid I wanted to be older . . . . . this CRAP is not what I expected ! RIP 09/08/2018

View ronniebo's profile


130 posts in 4115 days

#3 posted 03-27-2012 09:22 PM

Dave, can you show us a foto of your system. Mine works perfectly, and of course, it is another variation on what everyone else has built, though the basics are the same.
Something very simple must have changed for you.
Ron in Sunny Hobart

View DaveTPilot's profile


282 posts in 4748 days

#4 posted 03-27-2012 09:50 PM

Hey guys, let me first say that I, in no way, am criticizing the Thien design. I know it works great for many people. It did not work for me with my system. Did I make an error in building it? Maybe. I don’t have any pictures but it looked like everyone else’s except that I used a 4” PVC pipe as the outlet. Maybe it was sticking down too much? I should have tried to pull it up until level with the top. Oh well.

Anyway, I think it is a fantastic design! I was probably not careful enough. I have abandoned that design and used my own idea. Giving credit where due, of course, I too used a baffle to limit the amount of turbulence upon the collected chips and dust. I used my stock lid, slightly modified for better fit, cut most of the bottom of the trash can off, added a baffle near the bottom and built a chip bin.

The baffle I used is a full circle about 3” smaller than the diameter of the can, and 3” from the bottom. It works unbelievably well. I made some video and will post.

Again, kudos to Phil Thien who started this band of obsessed dust monkeys! LOL

-- How valuable is time to a person who spends his disparaging the beliefs of others? --David Berthelette

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