J. Phil Thien's Projects

I'm definitely putting this modification on my (already too long) pending-projects list; thanks for the nice simple design! (I was wondering how I was going to hold the disk in place...) Two questions, if I may:

Sanity check 1: The drop slot should still end shortly before the inlet port, right? (IE, the solid area starts just at the point of highest airflow, where it can best prevent scrubbing.)

Sanity check 2: Has anyone determined whether 2/3-circumference is still the best slot length in this approach? In Phil's original version, and Vaughn's, the circulating airflow was obstructed at that point by the inlet tube/neutral vane. It's possible that this interacted with the slot length, and with a side-injected chamber a different slot length might be worth trying. Or it might not, or it might not be worth the effort to experiment with, but if anyone has actually tested it I'd be interested in hearing the results.

[Afterthought: Ah, I see -- this is effectively a pressure (as opposed to suction) Top Hat design, with separator suspended rather than attached at the periphery for simplicity's sake and to avoid interfering with bag attachment. Nice. Now if we can just come up with a way to replace the bag with a barrel...]

Sleetings and Granulations, it being December... though here in Northern BosWash we're still seeing temperatures approaching 60F.  (That's OK, we had plenty of white stuff last year.)

Brief self-description: I consider myself an educated novice as a woodworker -- I know a lot of the principles, can talk a good game, but am still in the process of setting up the workshop so I can actually start Doing Something. (Too many hobbies, too many projects, not enough organization.)  As a woodworker, I make a good locksmith. And as a locksmith I make a good programmer, which is my real paying gig.

Obviously the Thien Baffle is what drew me in here. (Or separated me out?) The most Baffling thing is why nobody invented it sooner; quietly brilliant, Phil.

I've recently acquired a Harbor Freight dust separator, which I'm planning to initially mod as per Vaughn's approach (http://www.jpthien.com/smf/index.php?topic=145.0)  -- though I'm still on the factory floppy filter rather than having converted to canister.  I think I'd like to initially try it without the neutral vane, for the sake of simplicity. (And because it feels like not having circulation in the chamber obstructed might be a Good Thing. Or might not.)  Is the 1/3-2/3 division still considered optimal for a side-injected chamber, or have folks concluded that it could benefit from a bit of fine-tuning?

(Actually, that monster's big enough that I could almost install the separator inside the existing case.... Another "alas", I don't think I could get away with just building the vortex chamber to enclose the existing filter.)

The standard Thien design has the extraction slot on the bottom surface of the chamber.

I find myself wondering whether permitting the  slot to extend up the side of the cyclone chamber slightly -- and having the cyclone be a smaller diameter than the enclosing container -- would allow momentum to throw material out of the cyclone chamber and thus aid separation ... or if this would be counterproductive because it would increase airflow in the outer chamber and thus permit material to be "scrubbed" back in... or if it'd simply produce too much turbulence.

Any idea?


(I have a 1980-vintage 16-gallon Sears vacuum for which filters have become hard to find. I'm pondering whether cyclonizing it is worthwhile, or if simply buying a real dust extractor makes more sense. Or, possibly, both. I don't think it's amenable to turning into a sandwich, alas.)