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Thread: Can two stacked DC's work better than 1 bigger one

  1. #1
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    Can two stacked DC's work better than 1 bigger one

    Running into a problem in that my Laguna combination jointer/planer doesn't do a good job of chip collection with my 2HP Harbor Freight dust collector. (I've enlarged the input to 6", short run of flexible pipe, etc. to no avail - the planer bed fills up with chips.) My shop is a space challenged 2-car garage, so footprint is extremely important.

    My question is, considering how cheap I can get another HF 2HP dust collector, can I roughly double the cfm by buying another unit and just using the motor/impeller and T'ing it into the intake and output ducts, using the same Wynn Engineering filter and collection bag? This would be cheaper than plan B, which is buying a larger impeller/housing from Grizzly (their 12.75" one) and using that to replace the 10" impeller on my Harbor Freight unit.

    Plan C is using my Shop-vac and building a collection box to sit on the planer table while jointing to collect the chips. This seems so inelegant, and noisy (clearly noisier than two dust collector motors.)

    What do you think is my best approach?

  2. #2
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    Hi Alan

    A jointer shouldn't need that much cfm to collect chips. I don't have a Laguna jointer, but I can tell you what I had to do with my Shop Fox (Grizzly) 8" jointer. The inside of the dust chute (coming downhill from the cutter head) was open on top on mine. This ruined the airflow stream. Following advice from other owners, I taped a cardboard spacer inside the chute in order to fill the gap. Viola, perfect chip collection.

    Again, I don't specifically know about your machine, but you might want to unscrew the plastic DC outlet and have a look at the chip path. Cardboard and tape is pretty cheap.

  3. #3
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    Since it's a combo machine, it has a large metal hood collector that sits under the cutters when it's jointing, and over them when it's planing. I can't see an easy way of modifying it.

  4. #4
    I do agree that yr problem is probably best solved by inspecting the path rather than adding more 'suck'.

  5. #5
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    +1 on closer inspection. I collect an amazing amount of chips off my jointer and planer with a 1HP Delta with an AFF top bag. I have a cyclone for other "dustier" machines in the shop. It seems like you are not getting good airflow, chips are snagging somewhere in the path rapidly creating a dam or you are taking very large bites out of your material. Its easy to be a bit confused when I'm not standing there watching it happen but, something just doesn't seem right and I don't think its the draw.
    "The Danish government believes that if we train 5,000 designers, and produce
    one Hans Wegner, the money is very well spent." - Ole Gjerlov-Knudsen

  6. #6
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    Taking about 1/25th of an inch bites (don't ask, there's a wierd scale on the machine), so I don't think that's it.

    At first blush, it looks like the dust collector is engineered to be too short. It should extend more towards the infeed table under the knives. That would solve the problem (although it would need more room to pivot), but it would be a bear to modify it.
    Last edited by Alan Lightstone; 03-18-2010 at 11:41 AM.

  7. #7
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    Alan,

    To your original question, you could run two DC's in parallel and increase your CFM. Running them in series could possibly overload a motor. I have severe space concerns in my shop, and have run two 1 hp DC units in parallel for several years now. Works for me.

    -Jerry

  8. #8
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    Alan,

    Which Laguna combo machine do you have?

    I agree with others- before I got my 3hp DC, I used a little 1hp machine on my jointer and planer (6" and 13" respectively) and it worked fine. This sounds like a design flaw with the dust collection path rather than a CFM problem.

    You said the issue comes up when you're planing. Does that mean it works fine when you're jointing? If so, there's your evidence that it's a design issue.

  9. #9
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    I have the 12" SCH Jointer / Planer. The issue comes up mostly with jointing. It is far less of a problem when planing.

    I also believe it is a design issue. If the collector chute was longer and carried over to the infeed side, there wouldn't be a problem. It would make pivoting the dust collector chute more difficult, more airflow might be needed and the dimensions would need to be more precise. But it could be done.
    Last edited by Alan Lightstone; 03-18-2010 at 3:42 PM.

  10. #10
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    Not a Laguna but Jet 12" J/P

    I had a problem with chip collection in planer mode. The problem was the plate that moves when swinging the hood. It would "fly" in the air stream when flipping it without removing the vacuum. I'm not familiar with Laguna. Does it have some sort of diverter or flap in the D.C. mechanism that isn't positioning properly?

  11. #11
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    It does have a flap, and does seem to be positioning itself correctly. I think the problem is that it doesnt extend far enough under the infeed side of the jointer, so chips escape under that side of things. If it was about 3" longer, it would work like a charm.

  12. #12
    Quote Originally Posted by Alan Lightstone View Post
    Taking about 1/25th of an inch bites (don't ask, there's a wierd scale on the machine), so I don't think that's it..
    It's stealth metric. 25.4mm = 1"

  13. #13
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    Quote Originally Posted by Caspar Hauser View Post
    It's stealth metric. 25.4mm = 1"
    LOL, though my brain hurts with that.

    Still haven't given up the idea of stacked HF motors / impellers wye'd together with 6" hose. That HF DC is just stupid cheap at this point.

    Haven't decided if I'll do it (the noise and addition of even more 6" flexible hose is what's holding me back.) I'm sure it would suck like nobody's business (there's a reason why planes have dual engines instead of just 1 huge propeller.)

  14. #14
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    I don't believe running them in series would actually help you much. They are running at their volumetric efficiency with no load, and adding another that has the same flow would not add as much I believe as running them in tandem. there would be some small gain I am sure but not proportionate to the additional HP needed. The fan can only spin as fast as the motor will let it, and that would be your limitation. If your second unit had a faster fan speed then you would see a gain.

    I am just guessing using my experiance with turbochargers and superchargers as a basis for my guess, but the principals are the same. In a twin sequential turbo setup the second turbo spins faster or is of a larger size spinning the same but flowing more air, and so a gain in air density.

    I'd just get a bigger turbo...

  15. #15
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    Quote Originally Posted by Larry Edgerton View Post

    I'd just get a bigger turbo...
    I know. Just kicking myself for buying the HF DC if it isn't powerful enough for my Laguna.

    I'm also going to try to build a collection box wyed to the 6" hose and plumbed to 4" or 2.5 hose that will sit on the planer bed when I'm jointing. If that can suck in the shavings, it will solve the problem, though in a McGyver sort of way.

    Still really curious if substantially increasing the suck from the 6" hose to the Laguna would solve things. If it doesn't, then it's not worth the time and money to further modify or replace my present 2HP HF DC.

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