Downdraft table

I am starting to think about designing an building a downdraft table. All the ones I have seen seem to have a squirl cage type blower and a set of filters. I was thinking that since I have all this cyclone DC power, why not run ducting to the DC system over to the downdraft table instead of a blower an filters? That way there would be no need to clean and replace a separate set of filters. Anybody have other thought on this idea? Also, could someone point me in the direction of some downdraft table plans or any other ideas that might be helpful in designing a downdraft table.

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Originally Posted by Larry Browning

I am starting to think about designing an building a downdraft table. All the ones I have seen seem to have a squirl cage type blower and a set of filters. I was thinking that since I have all this cyclone DC power, why not run ducting to the DC system over to the downdraft table instead of a blower an filters? That way there would be no need to clean and replace a separate set of filters. Anybody have other thought on this idea? Also, could someone point me in the direction of some downdraft table plans or any other ideas that might be helpful in designing a downdraft table.

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Not positive, Larry but, if memory serves correctly, I believe Terry Hatfield has done something similar, if not exactly what you speak of. I don't have the time right now, but you may want to do an SMC search for that to get more info. Keep us posted...:) :cool:

Yes...Terry's website has the info at http://www.shoptours.org/shop_tours/...-hatfield.html. It's a wonderful website! He also has made the Wood overarm dust guard for the tablesaw.

You can also purchase something similar in two sizes. I believe JET, Delta and Grizzly have them. They connect to 4" dia duct.

The downside to using your dust collector is air volume. These tables like a high volume of air flow which is why squirrel cage blowers attached to the table with no ductwork are perfect. On the other hadn, your dust collector is more low volume, but high pressure, which is more ideally suitef for ducted collection systems using small 4" and 6" dia duct.

However, I must admit, I have never used one of these types of pan system. But experience tells me that a 4" dia ducted system can't move the proper volume, but perhaps a 6" ducted system can.

Hi Larry - I built what sounds like a similar feature into my workbench when I made it. It's pretty simple and effective. I built a ramped bottom box under the bench, and drilled a series of 5/8" holes above where the box mounts totally about 2 square feet. There's a 4" DC port and blast gate hooked to the box. It comes in handy for cleaning off the bench too, but it's not too friendly to screws. :rolleyes:

Terry has a sanding "box". It is a very simple box that is portable. If I made something similar I would need to have a pretty long piece of 6" flex hose that would have to lay across the floor. I was thinking more of an actual downdraft cabinet type thing. I already have a 4ft square assembly table that I was thinking of modifying to include a downdraft table. I thought I could run some ducting under the floor and come up right in the middle of the cabinet. I could have a blast gate behind one of the cabinet doors or maybe not even a door, just an open space where I could get to it. The only disadvantage I can think of is it not being portable. But the idea of not having to deal with filters seems like a pretty good idea to me.

If and when I get around to building my new 4x12 bench, one end will have a 2x4 area on top for sanding. Maybe a piece of 1/4 pegboard for holes. Enclose that portion of the bench underneath, then hook ductwork to it. I have my ductwork under floor, so would be an easy hookup.

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Originally Posted by Steve Clardy

If and when I get around to building my new 4x12 bench, one end will have a 2x4 area on top for sanding. Maybe a piece of 1/4 pegboard for holes. Enclose that portion of the bench underneath, then hook ductwork to it. I have my ductwork under floor, so would be an easy hookup.

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This is a thread I will be watching, I want to do the same thing steve is talking about.

Try here:

http://billpentz.com/woodworking/Downdraft.html

I have not tried it but Bill usually has tested stuff on his site.

Good luck

Phil

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Originally Posted by Phil Maddox

Try here:

http://billpentz.com/woodworking/Downdraft.html

I have not tried it but Bill usually has tested stuff on his site.

Good luck

Phil

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This is not what I am talking about. I am thinking about a cabinet hooked up to the dc ducting. I am wanting input as to the pros and cons of hooking this up to a DC ducting vs a built in blower/filter arrangement.

I have a downdraft hooked up to a cyclone dust collector system.

It seems to work very well, however that is subjective as I don't have any means to test it. I can watch the sanding crud getting blown off the disk of my ROS and sucked into the table.

I have a hose to the outlet of the ROS which is hooked to the same duct via a seperate blast gate. That table was simple to build as I stole the ideas from several websites.

I can't seem to locate the digital camera at the moment but I'll try to get some photos posted. It is basically a big box of 2x material with a funnel inside to a 5 inch hook up.

I haven't used it much as I just started on projects (have been setting up the new shop building) but so far I have been happy with it.

Joe

Found the camera now if I just do this right.

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The first is the dual blast gate system. No the small hose isn't hooked up yet but it's on the to do list.

The second is the top and the hardboard I use to cover up unused areas and the third is the "funnel" inside. That is built of 3/16 hardboard pinned to a 3/4 plywood bottom strip.

The top is 3/4 MDF and the overall size is 24x36 or so. I forgot to measure it when I was out taking the pictures.

I have access to a CNC router (next best thing to owning one is having one to use :D ) so I used that to make the top but pegboard with enlarged and countersunk holes would work also.

Hope this helps

Joe

Larry - I built one a couple of years ago and it's hooked up to a 2 HP Cyclone. Per Oneida's suggestion (that they wouldn't put in writing) I ran an 8" duct off the main 9" trunk. This comes up from down below and wyes off into two 6" gated ducts. The box is about 28" deep, 48" wide, and 9" tall. I built hinged wings on either side that (in theory) help contain dust. The interior of the box has sloped baffles which I guess help direct air flow; but have no way to prove it.

There are about 304,984 1" diameter holes in the top spaced about 2.5" o/c as I recall, and drilling and routing a rounded over edge on each one was a miserable chore. There are intentionally too many holes resulting in more square inches of hole than square inches of duct. But I did it for flexibilty. When doing small stuff I lay some 1/4" scrap luan over the areas that I won't be using and this markedly improves the suckability of this thing.

I coated the top with some non-skid paste stuff I found in Rockler's catalog and wish I hadn't since it tends to scratch up what has just been sanded. So now I have to lay down an old fashioned router mat for protection. It's an open weave thing so the air flows right through it. Should have spent the effort to put a really good finish on it instead.

It actually does work quite well, although I don't use it that often. But when I do, I'm pleased. Here are a coupla pics.

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