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Thread: Router Table DC Question

  1. #1
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    Router Table DC Question

    I'm making progress on the new RT I'm building. Now, I have a question about DC for it.

    I have two Rockler RT DC ports, one on the fence, one in the chamber that holds the router. Both ports are round, 2 1/2" in diameter. If I have it figured correctly, the square inches of each port would be appx. 5". Correct??

    Each port has its own blast gate. The router chamber will have a door. Does this mean that I will need to have 5 square inches of air holes either in the door or sides of the router chamber? Does it matter where the air holes are for the chamber? The DC port in the chamber is located at the bottom of the rear vertical partition of the chamber. Do the holes have to be in the door directly opposite the DC port?

    To the left of the router chamber will be a stack of drawers. There will be 1/2+" of space between the partition and the drawer sides. The back of the table behind the drawers will be open (I think!). Can I cut a 1" slot 5 inches long (or longer) in this side partition to provide the air flow area, rather than in the door itself?

    Should I decide to put a back on the table, behind the stack of doors, am I correct in assuming that I would need to have at least 5 square inches of holes cut in the back also if I put the slot in the partition between the router chamber and the drawers?

    Thanks for your help in answering my questions about this project. You folks really are a big help and I appreciate your input!
    Stephen Edwards
    Hilham, TN 38568

    "Build for the joy of it!"

  2. #2
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    Yes, you will need intake openings to provide make up air for the router cabinet.

    The openings should be larger than the duct size, perhaps twice as large to reduce losses.

    Provide intake air low down, exhaust near the top.

    Regards, Rod.

  3. #3
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    I suppose there is a rule of thumb like equal inlet vs. outlet area. I made a temporary door for my cabinet and made various holes in it till I found the best collection (sometimes covering some if I got too aggressive). I ended up with a little more area entering than leaving with the entrance holes directly across from the exit. When I upped my DC power I had to add more holes as the DC was trying to implode my door ;-)

    That was just the results of my trial and error and I'm sure there can be more science applied than required but, that's what makes this forum so fun. I think most will agree that your exit should be near the floor to prevent any chip buildup. through a design flaw I ended up with about a 3/4" lip at the bottom of the motor enclosure. I rounded the cutout to make a sort of bell shaped exit point and have had no issues. I wish the bottom of my table saw stayed as clean.

    P.s. I also try to keep my throat plate sized a bit larger than the bit to allow air to flow in that direction as well as out the fence port. This rule is out the window if I am working small parts; safety first.
    Last edited by glenn bradley; 03-13-2009 at 1:29 PM.
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  4. #4
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    Thanks for input guys.

    Rod: Why do you suggest that the dust port in the chamber be near the top of the chamber. I don't understand that. The fence has its own dust port above the table. Seems to me that if the chamber port is near the top of the chamber I'm going to end up with a lot of dust collecting in the bottom of the chamber. Perhaps I'm misunderstanding your suggestion.

    I will for sure have more intake opening space than the the surface area of the dust port in the chamber. Thanks for that suggestion.

    Glenn: I like your idea of a temporary door and using trial and error to get the correct amount of airflow. By doing that, I'll be able to build the finished door ONCE! I'm going to build a clear polycarbonate door framed in wood to match the band on the top, cabinet facing and drawer fronts.

    I've built the bottom of the chamber so that there will be no lip at the bottom of the exhaust port. Actually, it's a tad lower than the sloping "floor" of the chamber. I've also installed sloping side pieces in the bottom so that all the dust is " routed" (pun intended ) toward the port opening.

    The reason that I has asked about the intake openings being cut into the sides of the cabinet, rather than in the door, is because I did a test with a solid piece of plywood covering the door opening in the cabinet. I noticed a significant reduction in the noise level when the router is turned on.

    Thanks again for your input and suggestions.
    Stephen Edwards
    Hilham, TN 38568

    "Build for the joy of it!"

  5. #5
    It sounds like trial and error might be the best way to arrive at a solution. Perhaps you could make a slot with an adustable baffle that allows you to experiment with different air flow into the lower chamber. Better yet, if you have an extra blast gate, use that.

    There's a reason why I put my intake slots up towards the top of the chamber - I wanted air to pass by and around the router to perhaps help cool it and remove dust from it. I don't think I would put the holes in the door if I were you. It just doesn't seem like there's much benefit to placing the intake holes / slots across from the outlet. I think your router's motor fan and everything else going on in the chamber negates the notion that air will flow straight across the chamber and out the outlet.

    I have some video closeup of my lower chamber while I'm mortising with an upcut bit. There's a ton of chips and dust going into the lower chamber, and to be honest it looks like a friggin tornado in there. The notion of dust flowing straight out isn't happening in my setup.
    John Nixon - Buffalo, NY

  6. #6
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    Thanks, John, for your suggestions. The adjustable baffle sounds like a good idea and easy enough to rig up. In fact, I think I do have an extra blast gate laying around.

    Thanks again.
    Stephen Edwards
    Hilham, TN 38568

    "Build for the joy of it!"

  7. #7
    Someplace I saw one of the slickest built-in blast gates - actually there were a couple.

    One was acrylic door w/ acrylic gate and the other birch ply door w/ an acrylic slide blast gate built into it. They each operated the same but the gate was larger on the ply to view inside better- the slider was built into the door and could be easily adjusted right there at the front while looking into the chamber and seeing what was happening internally. Seemed awfully simple to do if one does it while making the table. Next table I do that is #1 of my things on the "want to include list"

  8. #8
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    Quote Originally Posted by Stephen Edwards View Post
    Thanks for input guys.

    Rod: Why do you suggest that the dust port in the chamber be near the top of the chamber. I don't understand that. The fence has its own dust port above the table. Seems to me that if the chamber port is near the top of the chamber I'm going to end up with a lot of dust collecting in the bottom of the chamber. Perhaps I'm misunderstanding your suggestion.

    I will for sure have more intake opening space than the the surface area of the dust port in the chamber. Thanks for that suggestion.


    .

    Hi Stephen, I made several assumptions in that choice;

    - the router will draw air from the top of the motor, and exhaust it at the motor base. When in the cabinet this will be up draft

    - convection will also help the airflow in an upward direction

    - bring clean air in the bottom so that the router motor will have clean air going into it.

    - chips will enter the cabinet from the top, capture them as much as possible at the source

    Regards, Rod.

  9. #9
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    Thanks, Rod, for your explanation. Here's what I think I'll do, after reading the posts of all the folks who have chimed in with suggestions:

    I already had the RT chamber dust port at the bottom rear of the chamber. I think I'll install an intake port above it near the top of the chamber, with a blast gate installed in that hole.

    This way, I can experiment to see which way works best. I can also swap out the intake and the dust port until I find which way works better, top or bottom for the exhaust.

    Thanks again.
    Stephen Edwards
    Hilham, TN 38568

    "Build for the joy of it!"

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