Down Draft Table

[Paul Kinneberg]

Hi all. I am incorporating a 24" by 36" down draft table into my table saw out feed table. I will use my 3hp Super Dust gorilla for the suction. My question is should I use 1/2" or 3/4" holes? Does it matter? Not sure it matters but fyi the table is about 20' from collector. Thanks for the input.

[glenn bradley]

Take the area of your duct (4", 6" whatever), your holes should exceed that area by about 20% in my experience with my router enclosure. Any less and I was not getting good airflow.

[Larry Browning]

I've been banging around the idea of a downdraft table for quite some time now and I can't decide anything. What made you decide to use the DC to provide the suction rather than a separate squirrel cage type arrangement?
I have been leaning toward that route, but I was wondering what made you decide to use your existing DC. I can still be influenced by sound reasoning.

[Cliff Rohrabacher]

What about a table that you can tune the suction for any given application by making the holes into little valves??

Use two layers of sheet stock for the top, one on top of the other.
Clamp 'em together and drill 3/4 holes through the layers.
Build the table top so the lower sheet can be shifted laterally with respect to the upper. Can do this by moving the lower layer with a jack screw sliding it in a dado or just let part of it stick out so you can tap it..

It only needs to have enough room to slide as the diameter of your holes plus a scoosh for good measure. so 7/8" would be plenty for a 3/4" hole. It is important that the layers must be in contact with each other.

Can build it so that the lower sliding layer is composed of more than one unit giving you the ability to shut off parts of the table raising the air flow elsewhere.

Haven't done this but it sounds good.

[Mike Hill]

Hi all. I am incorporating a 24" by 36" down draft table into my table saw out feed table. I will use my 3hp Super Dust gorilla for the suction. My question is should I use 1/2" or 3/4" holes? Does it matter? Not sure it matters but fyi the table is about 20' from collector. Thanks for the input.

Paul: Post a picture when your done. I think this is a great idea for saving space.
Mike

[Paul Kinneberg]

Larry not so much sound reasoning as economics. I have been working on my new shop for about 18 months just now starting to get things set up and thought it would be a good idea. Since I am also installing the dust collector i figured there wouldn't be much additional expense. I will let you know how it works. Mike I will also post pictures when complete. Thanks.

[Paul Kinneberg]

Here are some Pics. Just need to finnish the manifold for my dust collector next weekend and pick up the metal legs my brother fabricated for me.

[Wes Bischel]

Paul,
That looks outstanding! Not only from a functional standpoint, but from an aestetic one as well! I will say black and white wouldn't stay that way for long in my shop!:rolleyes:

Great design!
Wes

[Jan Williamson]

Wow Paul! How inspiring! I have been working on my "island" which includes TS, router station, outfeed and downdraft. I have everything ducted to the main DC cyclone. I have been pondering whether or not to laminate the whole thing, but after seeing yours, it's a no-brainer!!! Did you drill the holes with any kind of special bit to go through the laminate?(sp?) Did you use a jig?

[Paul Kinneberg]

Jan
I used a 3/4" forstner bit in my cordless drill by hand over 3 nights, 160 holes. I jig that would hold the drill sqaure would have been nice. Also I used 2" wide 3m tape to mark the holes but it also help save the laminate from scratches a couple of times. By the way its black laminate on birch plywood I left the edges natural with a coat of poly.
Paul

[Mike Hill]

Thanks for posting the pictures Paul. Gives me some great info if I decide to do this on my out-feed table.
Mike

[John Nixon]

Here are some Pics. Just need to finnish the manifold for my dust collector next weekend and pick up the metal legs my brother fabricated for me.

Hi Paul, the table looks great!
One bit of advice - I had read somewhere that counter sinking each hole greatly improves air flow. I'm sure that the thought of revisiting 160 holes isn't attractive.

You could use your router with a bearing guided chamfer bit and plunge into each hole. It would be neat to have the system turned on while you're doing it to suck up all the dust from the router!

John Nixon - www.EagleLakeWoodworking.com (http://www.EagleLakeWoodworking.com)