J. Phil Thien's Projects

Sounds great!! Definitely post up some pics soon. Yeah cast iron is softer... Maybe some tapping oil would help with the steel?

So you think in general, a smaller diameter is better?

The way I understand it, you should have the discharge of the blower "land" on the 120 deg portion, to encourage it to go around the outside instead of buffeting around.

I got my DC second hand, so the felt back was the best option. And it's MUCH larger than the stock bag, like a full foot taller, I literally clamp it to the cieling joist in my basement (well floor joist), because the pole is too short! So I think the larger area makes up for the tighter weave.  But yeah, no scientific comparison!

Thanks. I emailed a concrete supply place near me, no bueno. They carry it, but none in stock. I'll keep my eyes peeled. It's not urgent anything.

I can't speak to the wynn filter... I put a felt bag on mine. But mine is also an older model, and turns out the funnel ring inside the DC was BELOW the blower discharge! So rather than trying to remove it, I inverted the unit...

Before: See the ring?



Then I cut the baffle. It's small enough that it is secured via 3 screws from the outside. I was worried about splitting the MDF, but it holds nice!



So now you can see the funnel ring is upside down... but I don't think that effects the performance much. I could alwaus cut aNOTHER ring for the inside if I had to...



So then I built a rack to hold the unit. The original unit was supported by a metal cylinder attached to the motor. Flipping it exposed the fan, so I needed something to protect it. A bucket with some holes was a nice $2 fix shroud!



Finished product with my buddy JJ who helped me out.

Where did you get the sonotube? I can only find 18" in my area.... Looks GREAT!

The table is slightly below the saw table... Some day, I want to re-do the outfeed table, and I'll cut slots. The slots don't have to be precise, they just have to clear the miter bar! Simple enough.  My saw doesn't have a rear rail, so I just used the holes that the bar WOULD have attached to. You could also hang some angle iron on the saw by sandwiching it between the rear rail and the saw table.

The other thing that Greg brought up that I never really considered is the center stream. Basically the air right around the side of the pipe is experiencing friction from the walls of the pipe. So it moves slower. So larger pipe means more room for free flowing air in the center of the pipe. Simple but not obvious!

I tinkered with a  couple different iterations, but all in all nothing you couldn't do with a hack saw and a drill. In fact I think that's what I used... maybe a cutoff wheel in my angle grinder. Nothing fancy! I chose AL square tubing for the vertical piece because it resisted twisting the best, and wasn't heavy like steel.  The engle iron attached to the guard itself is a little flimsy, it's that stuff used for garage doors or whatever. It's really just stamped sheet metal. REAL angle iron would be better.   The 4 diagonal arms are actually leftovers from a mobile base kit I had.  They are steel, almost like C channel, nice and stiff. Then it was just a matter of playing around with holes and bolts. If you do an online search for overhead blad guard, I bet you'll come up with some good ideas. I can take better pics too.

Interesting idea... I think the main concern would be maintaining the area of the tubing when transferring it to rectangular.

Back to the pipe diameter thing...  It's not JUST the diameter. What I mean is, it's the diameter AND the length.  For instance, if you JUST have a 4" opening at the tool, and it immediately opens up to 6", yes that will impede some flow, but not as much as a 10 foot length of 4" pipe. 

How bout an experiment. Try sucking in air thru a paper towel tube.  Now cut a hole in in a piece of cardboard the same diameter and suck air thru it. I bet it's easier...  The air flow is necked down, but it's allowed to flow freely afterwords too, as opposed to being restricted the whole length of the tube.

Hope that example makes sense... If I think of an actual explanation, as opposed to an example, I'll let you know!

Quote from: coaster on April 23, 2009, 04:47:43 PM
nice outfill table, what is the notch for behind the kerf splitter? i have some ideas for an outfill table on my saw but due to the motor being behind there are issues.

did you build that top collector/guard? i need that! i've seen plans for them and they seem doable. the lower dust port does work but i still get chips shot at me off the top.

i hooked the trash can up to the saw today (first time) and cut the heck out of a 2x4 to make some dust and it is all in the trash can except what shot  forwards out the guard.

Thanks!! The motor on my saw is back there too, hence the short stationary section. The bigger part folds down, and it's on wheels now, so I can move it around (see below). The notch is there for the original guard/splitter which mounted out the back also like most saws. Now its just a place to sweep extra dust or scraps...

Yeah I built the guard myself. That's a PSI (Penn State Industries) plastic guard, which is only $25 bucks, and comes in a few days! the shark guard looks REAL nice, and someday I may get one, but this one was cheap, quick, and custom, the way I like it!! And I can completely move it out of the way (also below) for when I do dado cuts or blade changes.

 ;D

Well the original question is valid in that your separator IS before the impellor, but setup in THE most efficient way possible. Also I think having a side inlet is THE best way to go. Eliminating TWO bends, and possibly bends of a hose, will go a long way to improving your efficiency. 

Any way you do a separator, the air has to do a loop, and turn 90 degrees to go up the middle. That's where the inherent loss is. Reducing the rest is the challange!