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Thread: Jointer Dust Collection

  1. #1
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    Jointer Dust Collection

    I recently finished a dust collector installation in the new shop and just started on the first real project with it. I didn't expect it to grab everything from the jointer because of the open areas around the cutterhead but the amount of chips strewn about seems a little excessive. Does this look right to you guys after jointing about 25 board feet?

    IMAG0405-1024x768.jpg. IMAG0406-1024x768.jpg
    - Mike

  2. #2
    Nope. Something isn't right. My jointer/dust collection is far from ideal, but I'd have to joint boards all day to accumulate that amount of chip around it.

  3. #3
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    How big is your DC? Is there an opening in the top of the cabinet under the cutter head? Is the DC or DC hose connected securely to the chip chute discharge at the front of the jointer? Does the chute completely cover the bottom of the cutter? Are there louvers and are they open (see photo) And finally, most important, have you looked closely at the chip chute? Dust collection on older jointers was made to be done by shovel! The whole length of the rectangular chute, from the cutter head to the discharge opening at the front of the cabinet, on many (most? all?) of them is open to the (vented) cabinet. What that means is there is absolutely no air flow at or near the cutter, you are just sucking air from the cabinet and the only chips collected are those that are propelled by the cutter or fall down the chute by gravity- and a fair number of those can easily bounce out of the chute and onto the floor.

    The simple solution is to fabricate a top for the chute from metal, ply, etc.

    Dust chute on a Delta DJ-20



    Look! No top on the chute!!!!



    Plywood top:



    Plywood top in place (held with a screw from each side) so chute is now sealed from bottom of cutter head to discharge opening.

    Last edited by Alan Schaffter; 10-22-2016 at 12:35 AM.

  4. #4
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    The dust collector is a 3hp Powermatic, 1900 cfm, with 7" duct running into a cyclone preseparator and 6" duct between the cyclone and jointer. The port on the jointer was opened up to allow the 6" duct (see pic).
    There is a lot of open space around the cutterhead. I will check the dust chute to see if it is enclosed.

    IMAG0360_resized.jpg
    - Mike

  5. #5
    The only time mine does that is when the chute has a blockage.

    You have a pretty sharp 90 there you sure that's not causing an air flow problem?

  6. #6
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    Quote Originally Posted by Robert Engel View Post
    You have a pretty sharp 90 there you sure that's not causing an air flow problem?
    It's hard to tell from the original picture but it is tapered into the hood. I'm sure that it does add some restriction but I don't think it's excessive.
    Here's the inside:
    IMAG0413_resized.jpg

    I have the same dimension/type of boot on my table saw and don't have an issue with airflow there (that I'm aware of).
    - Mike

  7. #7
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    I have a magnehelic gauge measuring the back pressure between the blower and filters. I notice that most of my branches run between 1.1" and 1.5". This branch drops down to .4" so there is definitely an issue here. I unbolted the hood from the jointer and there is no change on the gauge.

    I may have the pipe from the jointer coming up into the wye too close to the cyclone. Also, the angle is a little sharp there. It's not how I had planned it, just the way it worked out. I didn't think that it would have that big of an affect on the airflow.

    IMAG0416 1.jpg

    Also, there is no blast gate on the 4" line running to the planer, the blast gate is just prior to the cyclone. I don't think that is the problem though because my table saw branch has a 6" and 4" line with much better airflow.

    Is the cyclone really that restrictive?
    - Mike

  8. #8
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    A couple of points-

    Does the chip chute totally enclose the underside of the cutterhead and is it sealed to the structure around it? It should.

    I can't tell how big it is from your photo, but the equivalent size, in sq. in., of the opening at end of the chip chute should equal that of the duct.

    You definitely need to put a blast gate on the duct to the planer to get max draw from the jointer.

    A comment about your ducting- I see you used low velocity wyes which are typical of (low velocity) HVAC installations. They are not designed for use in dust collection applications, where velocities can be 4000 fpm or greater, since they add too much turbulence and static pressure. You should use standard wyes.

    The low velocity wye at the intake to the cyclone will really cause turbulence in the cyclone and degrade separation. There should be a straight line of duct entering the cyclone that is nominally 10 (?) X diam. of the intake duct, i.e. 5' for 6" duct.

    This brings up another question- have you checked your filter(s)? It/they may be totally clogged.
    Last edited by Alan Schaffter; 10-22-2016 at 8:26 PM.

  9. #9
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    Air flow is like water--it is going to flow the path of least resistance. My suspicion is that the sharp angle on the wye coupled with the adapter are functioning as a fixed orifice restricting flow down that branch of the line. Since there is no blast gate on the line to the planer, it is now the path of least resistance (vs the path to the planer) and consequently, most of the flow is coming from that line.

    Can you cap the planer line (or install a blast gate) and then check the effectiveness?

  10. #10
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    Michael

    There is definitely not something happening properly there. I only have a Jet DC1100 dust with 4" flexible piping, and the jointer dust collection is many times better than what you are experiencing.
    You have an airflow problem with the jointer. Isolate the jointer and work backwards from there. You will need to close the other machines off, even if just temporarily to find out what is causing the issue. I suspect it is the way the jointer is hooked up to the system.
    "The first thing you need to know, will likely be the last thing you learn." (Unknown)

  11. #11
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    That appears to be an older jointer. As Alan demonstrates, back when men were men and respiratory problems were for wimps, dust collection was pretty unsophisticated. I would bet that the chute is open somewhere. Easy enough to check, just pull the side panel. If it is open on top it may be easy to fix. The Grizzly G0490X modeled after the Delta DJ-20, I did like so (Grizzly now encloses their chutes BTW).

    G0490X-belt-pulley-check-2011 (7).jpg

    A little caulk and some very short self tapping screws (heads on the inside of the chute).
    "A hen is only an egg's way of making another egg".


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  12. #12
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    Glenn and Alan, you are correct, the chute is open on the top and there is also a lot of open space on the backside around the cutterhead. I will enclose this as you guys have demonstrated but I don't think that is the entirety of the problem. I am getting low airflow at the duct inlet.
    - Mike

  13. #13
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    Quote Originally Posted by Michael Zerance View Post
    Glenn and Alan, you are correct, the chute is open on the top and there is also a lot of open space on the backside around the cutterhead. I will enclose this as you guys have demonstrated but I don't think that is the entirety of the problem. I am getting low airflow at the duct inlet.
    It sounds like we pretty much nailed your problems- fix the jointer chute, put a blast gate on the planer duct, and don't forget to check and, if necessary, clean your filters. Do all that and you should see quite an improvement at the jointer. It may still throw a few chips from the pulley side of the cutter head, but will do a better job collecting most chips and more importantly to your health, the fine dust you can't see!

  14. #14
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    Quote Originally Posted by Alan Schaffter View Post
    I can't tell how big it is from your photo, but the equivalent size, in sq. in., of the opening at end of the chip chute should equal that of the duct.
    The rectangular portion of the duct is 3.25" x 10" which is just slightly larger than the area of 6" duct.

    Quote Originally Posted by Alan Schaffter View Post
    A comment about your ducting- I see you used low velocity wyes which are typical of (low velocity) HVAC installations. They are not designed for use in dust collection applications, where velocities can be 4000 fpm or greater, since they add too much turbulence and static pressure. You should use standard wyes.
    Yes, I agree. The duct wyes are not what I was expecting; I spec'd lateral wyes and this is what I got. It was my ordering error though, so I could not exchange them. In two areas, I had to make my own lateral wyes because the HVAC wyes did not angle correctly and were too big to work. I didn't expect them to make a huge difference, I guess I was wrong.
    IMAG0417_a.jpg IMAG0419_a.jpg

    Quote Originally Posted by Alan Schaffter View Post
    This brings up another question- have you checked your filter(s)? It/they may be totally clogged.
    The filters are new and clean as this was the first real project I worked on with the dust collection in place. The cyclone seems to be separating correctly; there is a lot of fine dust in the collection drum.
    - Mike

  15. #15
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    Quote Originally Posted by Todd Mason-Darnell View Post
    Air flow is like water--it is going to flow the path of least resistance. My suspicion is that the sharp angle on the wye coupled with the adapter are functioning as a fixed orifice restricting flow down that branch of the line. Since there is no blast gate on the line to the planer, it is now the path of least resistance (vs the path to the planer) and consequently, most of the flow is coming from that line.

    Can you cap the planer line (or install a blast gate) and then check the effectiveness?
    I pulled the flex off the planer and noticed weak airflow so I'm going to have to follow Mike's advice and work backwards from the jointer to figure out what exactly is killing the airflow.
    - Mike

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