J. Phil Thien's Projects

Okay guys and gals, I have seen folks asking about this over, and over again, and I have seen Phil's answer that includes router table, or band saw and special jigs. I wanted to share with you my approach to the construction of a Thien Cyclone Separator lid. I have learned a LOT in the process of building my first one, and now the second is well under way. I hope this write up helps. I should note that this write up is done with the idea that it will be used for a 4" ducted system. If you are not using 4" adjust your sizes accordingly. Like Phil mentioned, there are no "plans" per se, and my solution may not work for your situation, but this is what I am doing to build my separator / baffles.

First things first, you need to obtain the materials to make your separator. I am using 3/4" MDF for mine since, honestly, it's what I have on hand. If had nothing on hand, I would have gone and grabbed some 3/4" sanded baltic birch, or Poplar plywood. For most builds a quarter sheet is really all you need, some need more than that... So here goes the shopping list.

        - 3/4" BB ply, or whatever material you chose. Pine is cheaper, MDF is even cheaper. Take your pick. If you go ply, get sanded, unless you want to sand your arms off.
      - 1/4" - 20 threaded rod. This is best purchased in 6' lengths. You will need to CAREFULLY cut this to shorter lengths making certain the threads are undamaged. Be comfortable with a file and possibly a thread chasing die.
      - 1/4" - 20 stop nuts A.K.A. Nylon insert nuts, nylock nuts, lock nuts etc... You will need 6 of these.
      - 1/4" fender washers. 12 of these
      - 1/4" - 20 standard nuts. 12 of these.
      - 4" S&D pipe nipple, OR 4" Dust Collection Hose Splice.
      - 4" S&D street elbow OR 4" Dust Collection 90 degree elbow.
      - Container. Your dust bin as it were. I am getting good results from galvanized steel trash cans.
      - Hot melt glue for a glue gun (and the glue gun) or clear silicone adhesive sealant.
      - sacrificial strip of lumber, or foam insulation or something to allow bit to cut through and not damage bit or floor. (or benchtop, or sawhorses, or... you get the idea I hope.)
      - 4" Dust collection hose, and clamps.

Next, you will need to assemble the tools needed for the project.

        - Router. Plunge or fixed base doesn't matter. Plunge is easier to start the cut with, a fixed base is a bit more dangerous to start the circle cut with.
      - Straight cutting plunge router bit. I used MLCS item #7751 3/8" dia, 1" cutting length, 1/2" shank plunge cutting straight router bit.
      - Rabbeting Router bit. I use MLCS #8366 9 piece rabbeting router bit, 1/2" shank. Set for a 3/8" deep rabbet cut.
      - Circle Cutting jig. I use the Craftsman branded version of the Milescraft 1203. If you don't have a circle cutting jig / edge guide for your router and want to buy this one, I STRONGLY advise you to immediately upon opening the box throw out the all plastic threaded knobs and replace them with 1/4" - 20 star knobs. I got mine from Rockler no problem...
      - Jig Saw with GOOD wood cutting blades. I have both a junk old Skil jig saw, and junk Black and Decker blades. They work, but are not ideal.
      - A means to sand the INSIDE of a circle. I am using an oscillating spindle sander, you can also use a sanding drum on a drill press to do the same job...
      - Work surface and clamps. I use junk sawhorses for mine and don't care if I cut into them.
      - Clamps to keep the work piece from moving on the work surface. 2 6 inch bar clamps work fine.
      - Hot glue gun if using hot glue.
      - Drill and drill bits.
      - Measuring and marking tools, specifically.
         - Sewing measuring tape. The flexible fabric kind to measure and mark the outside radius.
         - Straight edge with measuring scale. A carpenter's square SHOULD be enough, but might not be long enough.
         - Pencil.
         - LARGE drawing compass, or at the very least, a string.
         
Now that you have the stuff, we move on by measuring the top of the container, outside lip to outside lip. I am again assuming a trash can here.... An example.

   -Measure the outside lip to outside lip of the container in at least 3 different spots. Add those numbers up, and then divide by the total number of measurements to get your average. So for example your measurements are 19.5", 20", and 20.5" for a total count of 60 divide that by 3 for an average of 20. Now divide that number in half to get your radius (the space between the center point and the outside edge. That equals 10. Now that we have a radius, we know we want to overhang the edge just a hair to keep things from slipping in one way or another. Add 1/4" to that number. Now we have a radius of 10.25" right?
   - Measure and mark your sheet material. Say you are using a quarter sheet of MDF. Measure 21" up the long side, and using your square draw a line across, insuring it is square, measure the distances in a couple of locations to insure you have it right. You should have a sort of square, 24" wide x 21" high. Using your square line up the opposing corners of the square and draw a line corner to corner. This gives you the center of the square.
   - Drive the center point nail for the circle jig, and using your square, measure 10.25" from the nail, and draw a line.
   - Set the router up with the straight bit, and circle jig, Connect the jig to the center point, and adjust so that the INSIDE edge of the cutting carbide is touching the outside edge of the line you just drew. Lock the jig down.
   - With the work piece on a sacrificial piece, clamp it down so it won't move. Be careful to keep the clamps out of the path of the router.
   - If using a plunge router, set the plunge depth to 1/4", if using a fixed base, set the bit depth to 1/4".
   - Make your circle cut plunging or lowering the spinning bit / fixed base as neccesary.
   - Repeat the two steps above but adjusting depth for 9/16" depth, and finally 7/8", the final cut WILL protrude through the bottom. This is why we put it on a surface we can cut. This last cut you MAY need to move clamps around to keep the circle piece captive while you complete the cut.
   - Remove circle cutting jig, straight bit, and center point pivot hardware.
   - Repeat the above process but setting the radius of the circle jig to 9 - 7/8" for the baffle piece.
Now to cut the rabbet.
   - Set router up with rabbeting bit, set to make 3/8" rabbet, set bit depth no deeper than 1/2". I personally like doing 3/8" so that the distances are the same.
   - Clamp the circle to your work support. You WILL have to stop, restart the cut to move the clamps.
   - Make your rabbeting cut. I cannot succesfully do this via plunging, I simply sneak up on the cut and go to full depth riding on the bearing.
   - Test fit the lid. It SHOULD be a snug fit, if not, figure out what measurements were off and start over again.

Make the cutout for the baffle.
       - Using the sewing measuring tape, measure the outside circumference of the circle, divide by 3, and mark the start and end points on the outside edge of the disk.
      - Using your square draw a straight line from the marks you just made to the center point of the disk.
      - Measure, and mark 1.25" from the outside edge up on each of the lines you just drew.
      - using a compass, or string, pencil, and nail, draw an arc from the center point, around the long way to each of the 1.125" in marks you just made.
      - Using your jig saw, and possibly the drill / bits for starter holes, cut out the large radius notch.
      - Clean up with a sander if neccesary.
      
Cutting holes in the lid for the plumbing.
        - Center the pipe nipple / hose coupler and use it to draw the outline of the center hole.
      - use elbow and line it up to be as close as is comfortable to the edge close to the rabbet.
      - Use drill bit and create starter holes.
      - Use jig saw and cut out your holes from the lines you just drew being careful to stay inside the lines.
      - Using a spindle sander, or similar arrangement, "sneak up" on the fit for the plumbing so that you can just slide the plumbing through.
      - Sand the right side of the outlet of the elbow so that you can turn it in as close as possible to the side of the can.
      - Line up the baffle with the lid, and insuring that the holes and supports will not interfere with the plumbing, drill the 3 1/4" holes through both pieces at the same time. (This insures alignment.)
      - Insert elbow, align to get as close to the side as possible without touching, and hot glue in place, filling any gap between elbow and its mount hole with hot glue for a complete seal. Insure at least 1-1/2" protrudes for the hose to clamp to.
      - Cut threaded rod to 3 7" segments, clean threads on the ends. Install 2 normal nuts on each end, and a washer, allowing enough space to pass through the work pieces. Pass through from the inside, from the outside install washer, and lock nut.
      - When all 3 spacer rods are installed, adjust the nutsso that the distance is equal, and the elbow barely touches the baffle.
      - On the inside, screw the 2 nuts per side together in a "jam nut" configuration. This keeps it from backing off.
      - Insert nipple / hose coupler adjust to where the end is 2" from the baffle.
      - Hot glue the nipple / hose coupler in place the same way you did the elbow.
      - Connect inlet hose to elbow, clamp in place. If you are using S&D fittings, the fit will be snug, slip the clamp on, then work the hose onto the fitting and clamp it down. You are good to go. Same applies below.
      - Connect outlet hose to outlet, clamp in place.
      - Test.

On the web page http://www.jpthien.com/cy.htm I have two questions aboyt the photos:
1. There appears to be a wing nut in the center of the baffle on the underside. What is that for?
2. The baffle appears to be offset from center on the lid. Is this correct, or is it just a funny camera angle when the photo was taken?

In regards to #1. The wing nut. While that is Phil's photo, that wing nut isn't really part of the design per se. I believe the reason he has it there is simply to plug a hole in the hardboard he used.

In regards to #2. YES the orientation of the baffle to the inlet bend is important, and that is NOT an optical illusion. You want the solid part just starting as the air comes out of the inlet so it can ride around a bit before stuff drops into the can. I have seen (read I messed up and oriented it wrong) this done backwards, and scrubbing becomes a very real problem very fast...

Quote from: dbhost on June 30, 2009, 01:18:12 PM
...
In regards to #2. YES the orientation of the baffle to the inlet bend is important, and that is NOT an optical illusion. You want the solid part just starting as the air comes out of the inlet so it can ride around a bit before stuff drops into the can. I have seen (read I messed up and oriented it wrong) this done backwards, and scrubbing becomes a very real problem very fast...

I am confused by some of the pictures as well.  However I think that rfcomm2k's comment is based on a picture where the camera is not lined up with the center of the baffle AND lid.  So, it appears that the center of the baffle is not at the center of the lid OR the trash can.  This would result in an aperture (hole where the dust falls to the bottom of the trash can) that would look like 2 half crescents and some sort of hard to describe arc.  Bizarre.  This is most likely incorrect.

I think the center of the lid AND the baffle AND the trash can are all the same.  I think the aperture looks like a ~1 inch 240 arc.  The arc appears to start about 200 degrees after the inlet pipe and ends about 40 degrees before the inlet pipe.

Do I have that right?

-thanks everyone for contributing!

You are close to right. Yes the center of the baffle is indeed the center of the lid, and yes it is over the center of the trash can, drum, or whatever your vessel is.

The elbow in question empties out at the start of the solid part, not the drop slot, or aperature as you called it, so that they loaded air is slightly deflected away from the shavings / dust below.

The slot / aperature is 1-1/8" wide. I do not know why Phil designed it this way, and if it needs to be adjusted for larger sizes. For my HF 2HP DC I made the drop slot 1-3/8" wide by sheer measurement mistake and it still worked fine. On the one I am building for the 55 gallon drum, 4" pre separator the drop slot will be 1.25" wide. Right or wrong that is how it will be made.

Hope this helps, and sorry about the slow reply. I didn't notice your post for the longest time...

Quote from: dbhost on September 11, 2009, 01:06:50 PM
You are close to right.
...
The elbow in question empties out at the start of the solid part, not the drop slot, or aperature as you called it, so that they loaded air is slightly deflected away from the shavings / dust below.
...

Good thing you took your time as it gave me a chance to finish up my dust collector.

My inlet elbow starts at the beginning of the solid part (where the bottom plate meats the side of the container) but the opening is actually about 1/3 the way past that.  It looks just like the picture except I am using 4 inch S&D pipe and a 20" (approx diameter at top)  recycling can.

I believe it is doing a fine job - but wished it was trapping more of the fine dust.

I would say my Thien separator is removing about 75% to 80% of the saw dust generated from my table saw. The reset, I think, is ending up either on the floor of the filter box (which is about 4 x 2 x 2 feet - a really massive space) or on the filters them selves.   But this fine dust is really hard to quantify let alone collect.  (The generous space in the filter box was for a set of mini cyclone filters that I never implemented - as that design got more and more complex.)

As for the fine dust collection problem - I have noticed patches of fine dust clinging on the top of the bottom Thien plate.  I think I have see the same on pictures here of other people's Thien separators.  There seams to be a space of low turbulence on the way to the exhaust or outlet connection.  Is there a way to exploit this and remove the fine dust?

I was thinking of cutting yet another circle about 6" wide (in my case) in the bottom Thien plate and raising it about an inch.  This might give the fine dust travelling to the exhaust an opportunity to drop into the collection bucket.  But I think all this will do is create turbulence in the lower part of the bucket doing more harm than good.  Perhaps if this second opening could be isolated (a bucket with in a bucket) there would be no chance of additional turbulence.  Of course, my Thien design just got all that much more complex.  If I have any success with this idea I'll try to post a follow up.

Sorry for my dribble...  Is there a better thread to talk about modifications?  Or are you all ok w/talking about it here?

-thanks everyone for working and putting thought into this project.

I would probably start a new thread, and perhaps ask Phil directly about that issue with the underside of the baffle. I noticed it on mine too.

Yeah, 1/3 is the solid part, 2/3 is the open part...

I am a bit concerned you are only removing 75% of the dust though.... Is it just not getting picked up and ending up on the floor / on your saw (that would be a dust hood problem, or insufficient CFM etc...) or is it ending up in the filter / filter bag? (or whatever you are using if not using an off the shelf single stage DC).

As far as I can tell, and I have never asked phil about his concept here, but it seems like the idea is to keep the air spinning long enough for debris, and dust to fall out of the air stream, air smashing against the sidewalls of the container should do that... In turn the solid center section keeps the stuff that has already gone into the dust bin from getting sucked right back up into the filter.

You will always get some ultra fine dust that goes through your separator, but it shouldn't be much...

Unless I overrun my dust bin, I generally get about 1/2 cup of fine dust up into the filter / vac on my shop vac based setup for every 10 gallons of fine dust and mixed material I pick up.

My shop vac filter is pretty well caked too.... I use it primarily for cleaning the shop floor, and for my palm and RO sanders, so LOTS of fines get sucked up. I'm thinking a smaller diameter separator could help.

Quote from: dbhost on September 11, 2009, 03:17:48 PM
...
I am a bit concerned you are only removing 75% of the dust though.... Is it just not getting picked up and ending up on the floor / on your saw (that would be a dust hood problem, or insufficient CFM etc...) or is it ending up in the filter / filter bag? (or whatever you are using if not using an off the shelf single stage DC).
...

My set up is custom all the way and is built around a old AC 110 volt powered GE furnace "squirrel cage" fan.  I wired it up for both cooling and heating speeds. So I think the fan's CFM is not an issue.  I am seeing dust on the 2 20x20 high efficiency filters and on the floor of the (way over sized) filter chamber (which is about 16 cubic feet).  What I should do is tune up my Thien separator.  I used the original can's latching lid which now has to sit proud of the can because of the added wood.  Some weather stripping run around the inside rim should fix that.  Also, the can has drain holes I only taped over.  I suspect they are leaking and should be silicon sealed.  Last, I have to find a better way to mount the 4 inch S&D pipes.  They are currently fiction fitted and are "kind-of" staying put. After the tune up, I'll do a thorough cleaning of the system (which is quite large - my bad) so as to easily identify any new dust collected past the Thien separator.  Maybe I'll get better results then.

Quote from: dbhost on September 11, 2009, 03:17:48 PM
...
Unless I overrun my dust bin, I generally get about 1/2 cup of fine dust up into the filter / vac on my shop vac based setup for every 10 gallons of fine dust and mixed material I pick up.

Wow - really?  I definitely need to tune my system up!

BTW - where is most if not all your dust from?  I have been cutting plywood which tends to make fine dust.  I was thinking once I get my router table running that would produce larger dust and chips which may be easier to separate (i.e. I am expecting the Thien separator to work really well with the router dust).

Quote from: CharlieL on October 03, 2009, 10:04:59 AM
While air leaks are obviously not good, even after you do fix those leaks don't expect the seperator to get 100 percent of the dust, especially the fine stuff. Even the cyclones that are built for the masses don't get all the dust, especially the fine stuff. In my opinion, a seperator, and or a cyclone is designed to get the big stuff so the blower doesn't have to deal with it, and it cuts down on bag changes due to being full.

Yes, I understand this.  And I really appreciate the elegance of the Thien's design as I've tried to make my own cone shaped separators. My dust set up is totally home grown and I am (subjectively) seeing (actually feeing at the exhaust) some issues in air flow reduction due to clogged filters (about 800 sq inches of higher end furnace filters - I don't remember the MERV (spelling?) of the filters).  I haven't settled on the overall design so I haven't had a chance to clean everything out and install new filters to see if "tuning" my Thien separator will make a significant difference.

Right now I have a huge cavity in front of 800 sq inches of flat filters.  I was going to put my separator in there, but the dimensions of the "let's quickly put a Thien garbage can separator together to see if it really works" exceeded that of the cavity.  The cavity is about 2x3x4 feet.  Any suggestions would be appreciated (i.e. put a second smaller Thien separator in there, two tandem Thien separators in the cavity and get rid of the big one, where to get a 2x2 foot garbage can, ect...)

-thanks

Question on the plans: Exhaust air ducting...

Ok, the exhaust air leaves in the center of the 'top' of the baffle, that is the center of the 'lid'. 

How far down does the exhaust air duct extend below the top of the baffle or how much room is required above the bottom of the baffle to the duct to make sure it all works well?

In the pictures it looks like it is not even with the 'top' baffle and sticks in about half way between the 'top' and 'bottom' part of the baffle/lid.

TIA... Jack

That's about right. On my shop vac sized unit, the tube extends 1.5" down from the top, on the 55 gallon DC model, the tube extends 2.5" down. I did not measure super careful or anything, Just kind of shoved the nipple in there until it looked right and applied silicone sealant...

Phil,
I saw your article 2 days ago on how to build a cyclone separator.
It was exactly what I wanted for my shed/garage arrangement.
I was so incensed that I have modified it and built it and it is FANTASTIC!
Thank you so much for making my life so much easier, love your work.
My modifications:
I used 50mm PVC fittings for the lid - none of them are glued as they are a tight fit (for the moment) and that allows for a great deal of versatility. I may have to glue some pieces as it ages, but we will see.
The distance from the top plate to the lid is 120mm, to suit the fittings.
I have used a couple of swimming pool pipe fittings (Australian type) to allow rubber fittings at the tools and the vacuum.
I have also used a 60 litre steel drum as the waste receptacle, these are easy to come by from old oil drums.
The rest is pretty much your design. A great idea.http://www.jpthien.com/smf/Smileys/default/smiley.gif
I have attached a few photos to show how it was done.
I look forward to any criticism or comments and other worthwhile projects.

Hi Guys again - this is a veritable Pandorra's box! Since making my 1st top entry Thien Separator and then read quite a bit of the other related threads, I want to put a question to the forum after a little bit of preamble.
The Thien Separator does a wonderful job and I see no dust or chips entering my wet/dry vac.
1.   Given the separator is so efficient why wouldn't a non-filtered tophat unit be fitted to a can and directly vented to the outside air?
Comments please?

Oz... 
Venting to the outside is certainly a viable option.   However there are a few things to consider. if none are applicable, then it is your best solution... 

1) Legal.  While a private homeowner can open his garage door and spread his dust and chips to the atmosphere, few municipalities allow a commercial business to do so.  The SCAQMD (Los Angeles), requires a permit for ANY duct that exits a building (even passive chimney hoods).  It MUST be filtered, and you must document any emissions or contaminants contained in the exhaust.  Since California has Prop 65 which requires disclosure of any materials which containing carcinogens and most hardwoods will give you cancer if you eat over 12 boardfeet a day, you are technically spewing cancer to the community.  Fortunately, there are only a few isolated cases of enforcing these laws, but it is coming... 

2) Good neighbors.  That exhaust duct will also emit sound as well as air.  How close is your neighbor's bedroom window?  Or, your sleeping infant? 

3) Winter's are cold (even in SoCal).  For every CFM you exhaust, another CFM has to enter your workspace.  If you are conscious of the cost of heating or cooling your workshop, your utility money is blowing out the duct.  With a 600cfm blower, a 20x20x10' workshop gets the air replaced every 6.5 minutes.   

4) Ooops!  The Thien Separator works so well, you tend to forget it.  I assume that most of us have let their separator overflow at some time or another.  When that happens, 100% of your debris goes out the exhaust.  Will that become mulch in your flowers?  Or, did you just spray your neighbor's driveway?  (with his new Harley parked downwind...) 

If none of these factors come into play, then count yourself as one of the fortunate few who have a system that is simpler and cheaper to run than most! 

Hope this helps!
Jim