How Well Did I do?

[HorizontalMike]

I just built my first Thien Separator and would appreciate input suggestions on how well I did and any tweaks/adjustments I might need to maximize performance.  I have this hooked up to a HF 2hp DC with a single 4" hose at the moment.  The lower portion of the lid is beveled 10 degrees for a snug fit to 30gallon can.
*Is baffle max diameter start in correct place for 4" elbow?
*Is the input extension inserted low/high enough above baffle?
*Is elbow near/far enough from side of trashcan wall?
*Anything else I may have missed?

Thanks,
Michael

[bruegf]

The only thing I think you might need to change is to start the major diameter of the baffle just an 1" or so before the elbow and get the elbow as close to the side of the can as you can.  On the one I built (5" inlet/outlet), I started the major diameter right at the inlet and it separates all but a fraction of the finest dust.

Fred

[HorizontalMike]

Just to be clear; Looking down from above the unit in its operating position, should I rotate the baffle CW or CCW and by approximately how much?

My limited testing, with less than an inch of dust in the can, showed a couple of chips catching between the bottom of the elbow lip and the baffle where there is just a 1/4" of space.  My thoughts on my original placement of the elbow's distance from the outer wall was that I did not want a "complete" blockage along the outside perimeter (thinking no room for the cyclonic action except inward right next to the center output).  Thinking about cutting the elbow's lower larger lip nearly off, save for the inner 40-50% that directs the airflow outward.  What about lowering the baffle another 1/4" or so? It just seems that the elbow is acting like a big wall blocking the air movement.  Would/does this make sense?
Michael

[dbhost]

I see 2 fairly minor issues in an otherwise excellent build.

#1. You should rotate the baffle clockwise, so that the part where the drop slot ends is just behind the output of the elbow.

#2. And the same mistake I made on my HF DC build as well at first... The baffle should be about 1" below the elbow to allow stringy stuff like planer shavings to pass under it, instead of building up behind it and jamming the whole thing up... Ever since I dropped mine down, I haven't been able to get it to jam. And I plane a LOT of cedar...

[HorizontalMike]

#1. You should rotate the baffle clockwise, so that the part where the drop slot ends is just behind the output of the elbow.

#2. And the same mistake I made on my HF DC build as well at first... The baffle should be about 1" below the elbow to allow stringy stuff like planer shavings to pass under it, instead of building up behind it and jamming the whole thing up... Ever since I dropped mine down, I haven't been able to get it to jam. And I plane a LOT of cedar...

RE: #1 That makes more sense.  I thought about that but tried to follow the instructions to the "T".  This way you are almost using the deflection off the elbow to force the last remaining dust down into the slot.

RE: #2 I think I will go ahead and cut the entire lower lip of the elbow off and trim the upper lip some more so that the elbow rides closer to the upper lid.  That should give me the additional 3/4" or so that I need below the elbow without having to cut more 1/4-20 all-thread.  Additionally, I think I'll remove the PVC sleeves from the all-thread and add a couple nuts for an aerodynamically cleaner cyclone area.

Got to head to WC today and spend more money so this modification may take a day or so.

[toolguy1000]

I see 2 fairly minor issues in an otherwise excellent build.

#1. You should rotate the baffle clockwise, so that the part where the drop slot ends is just behind the output of the elbow.

#2. And the same mistake I made on my HF DC build as well at first... The baffle should be about 1" below the elbow to allow stringy stuff like planer shavings to pass under it, instead of building up behind it and jamming the whole thing up... Ever since I dropped mine down, I haven't been able to get it to jam. And I plane a LOT of cedar...

looking at the second pic above, should the elbow, where is was sliced to get closer to the canister's side wall, be moved counter-clockwise so that there is more of the 120 degree full diameter, not reduced by 1 1/8" in front of the sliced portion of the elbow that is between the baffle and the wooden top?

[HorizontalMike]

Well, I chopped up the elbow (not a pretty sight) in order to streamline and shrink its footprint.  I also eliminated the PVC sleeves to shrink those supports as well.  There is now more than an inch gap under the elbow to clear stringy debris, the elbow itself has been cocked forward a bit and the baffle has been rotated to end the cutout just before the elbow's output.

The silicon caulking is still drying so additional testing will have to wait one more day but I feel this should improve/maximize performance when using these 4" PVC elbows.  IMO, 4" DC elbows would have been a much cleaner and easier solution when building this separator.  Got ahead of myself and wanted to get this thing going  ;D:

[HorizontalMike]

Well, I got around to doing the final testing of my modified Thien Separator and noted marked improvement in the collection of the very fine dust as compared to my earlier build (see first above).  Though this was tested with limited amount of debris (less than an inch), I have to say that this separator performs on par with the Woodstock Separator ($26) I started with:

http://www.grizzly.com/products/30-Gallon-Dust-Collection-2-Stage-Cyclone-Separator/G3376

It cost me a bit more to build but I chose to build it, for the fun of tinkering, and with the idea that I might end up using it secondarily with my 5hp shop vac for my miter and my planer.  The bottom line is that it works.  How far one lets their debris can fill before emptying is a personal choice therefore I am not sure that it should affect the relative perceived ranking of either type of separator.  Again, this has been an interesting project and I learned a lot by going through the process.   ;D

[HorizontalMike]

Long term use of this "corrected" unit has been very successful and efficient +6 months down the road.  If you are considering building this unit, compare my mistakes from the first images posted with the corrections made to the final unit.  When installing the elbow, you have to be very careful NOT to block/impede the cyclonic airflow within the chamber.

Ugly does NOT count so rest assured that this unit works well as designed.   ;D

[tool49]

If you don't mind me asking, what is the purpose of the inlet pipe?  I don't see any in the original design, is there any advantage to putting what looks like a 2 inch length of pipe under the lid on the inlet side?

Thanks!

[Bulldog8]

Tool49, that pipe is actually the outlet or suction side. The elbow is connected to the dust source. According to Phil's findings and instructions the outlet pipe should protrude through the opening at a distance equal to 1/2 its diameter. So in this case with the pipe being 4" the outlet protrudes through 2", I have a 6" outlet so it protrudes through the lid by 3". This has an effect on the air stream, I assume that if the outlet were simply flush with the top of the lid more of the debris would enter the filter area of the machine. The setup shown in this discussion has the inlet elbow a distance above the drop plate. In my version I made a side inlet and ran the pipe flush with the drop plate and left a space of 1 1/4" above the pipe. My thought was that this would allow for better separation. I didn't test it in any other configuration so I couldn't say which is more successful, but both of us are happy with our builds, so it possibly doesn't matter very much.

[JTJ]

HM, as you found out, there were a couple of things that help.  As DBhost pointed out, and you corrected, you need some space between the inlet and the bottom baffle.  One thing I did on my inlet pipe was to take it to the band saw and cut it off 1/2" above the top horizontal of the inlet.  It left me with sloping inlet, and I used my jigsaw set at the approximate (well eyeballed) angle of the slope when cutting the inlet opening into the top baffle.  Some work with a rasp took care or any binding and a fair amount of hot melt glue took care of any discrepancies.  This gave me a much more angled entry into the top. 

I used an angled (all this was 4" stuff) dust port (Woodcraft - 4" Universal Fitting Item #144654) over the inlet, and this allowed me to clear the bottom of my 50-760 (YA 50-760 build), and this looked to be a smoother entry than just using a 90 elbow.  That said, as much as possible I will do top hat builds from now on to eliminate bends and the standoffs between the top and the bottom of the baffle, since if I use it to pick up shavings from hand planes and off the lathe, they now have a tendency to catch on anything in the air stream.

I know this is an older post, but I've seen my mistake of butting the bottom of the baffle to inlet made by others in newer posts, and hopefully the mods you, dbhost, and others to get the inlet off of the bottom baffle may need to be emphasized.  Not a problem for just dust collection, but a definite hangup when sucking up shavings (Obviously, I'm too lazy to just pick them up with a broom and dustpan).  I know from experience when the shavings start piling up at the inlet, they are getting sucked up into the dust collector and jamming as well in the body of the dust collector. 

When I get around to getting another section of all thread (the originals have been cut too short to drop the bottom), I'll leave them long enough to play with trying to find the best height for them to drop into the bottom baffle cutout.
JT

[HorizontalMike]

JTJ,
I agree, building a top hat design separator would be the best bet as it would eliminate the three supporting rods as well as the protruding elbow, thus cleaning up the airstream completely.  However, building something near the very beginning of one's woodworking experience tends to steer you into the easier task of building just the "Lid" design, which I did.  If the darn thing didn't work so well I would have continued on and built the cleaner model.  I still may build a top hat if/when I upgrade my HF-DC unit by elevating and turning the motor/fan to clean up the hose runs between the DC-to-motor and motor-to-"Thien Separator".  Only time will tell, but in the mean time this basic "lid" design continues to work great.

If push comes to shove (money, time, skill level, etc) then go with the easy Lid.  You won't regret it and the only thing you will be wondering is, "Why didn't I do this earlier?"