Down Draft Table - Number of holes

K

kentdvm

New member
Ed and Friends,

Got a crazy idea to build a down draft drill press table and it works great! Will post pictures when I get a chance. Have about 75 3/8" holes spaced 1" apart on the intersections of a grid. There's a 4x4 blank under the bit with holes on all 4 sides. Went with 3/8" as opposed to 1/4" holes because I wasn't planning to have many holes and wanted to get larger chips. Ran 4" PVC to the box. I made a bunch of test holes with a 3/4" forstner bit and it sucked the dust & shavings down beautifully.

I was concerned that the suction would not allow me to move pieces across the top, so I put a 2 1/2" blast gate on the opposite end of the box (got to use all that little junk somewhere). As it turns out, this isn't necessary but I now have a great hook-up for cleaning my workbench and attaching to orbital sander, etc. Just block the holes by laying a clipboard on the table top, hook-up the shop-vac hose and it's ready to go.

Here's my question: I'm thinking if I take the 4x4 blank under the bit and drill holes in it, I could also have a mini down draft table for sanding small parts. If I understand Bill's formulas for a down draft table correctly, I think I can add another 30-35 holes without compromising performance. From his webpage, I extrapolated that with a 4" duct and 3/8" holes you could have up to 115 holes. There is room in the box under the table, but wanted to double check before a ruin a perfectly good down draft table. What do you think?

Still loving my cyclone and recommending it to everyone I can. So nice to have a clean shop and be able to breathe while working. Keep up the good work!
Kent
 
Kent, I'd love to see some pictures of the table. I have in the back of my mind to build one, and would love to see your ideas. Thanks for the tipic! Jim.
 
Kent,
You have to share now. The only machine in my shop that isn't hooked up is my drill press because I just never came up with a good way of getting the mess. You're idea sounds great....let us see the pictures. I'm not clear about the 4x4 blank that you are talking about. Also, what overall size is the table? You're 115 holes is right for a 4" duct.

Ed
 
Thanks for replies! Sorry to post run, but had to go out of town for a week. Got some pictures I'll post of the table. Pretty simple table.

Started off with an old counter top from a kitchen island. About 36" x 14". Liked the finished edge on 3 sides so left it that size. Box underneath -- started with 1x6 pine and made it about 16 x 12. Used scraps and this size seemed to fit well. Didn't plan on using it for anything more than drilling, but glad it's a little bigger than necessary and can be used for sanding. With the hole pattern I drilled, you could make box 10x12 or even 9x11. Works great for drilling so far. Haven't tried everything just a 3/4" forstner bit.

I then drilled a 4" hole on one end and a 2 1/2" hole on the other. Ripped the width down to about 4 3/8" - 4 1/4" with 4"hole centered. Trying to limit height. Screwed to table top and screwed in bottom. The bottom sets within the box and blocks a little bit of the 4" pipe on the bottom. Opted to do this to keep height to a minimum - esp since this is a tabletop press. Total height is roughly 5" but I rarely drill anything thick enough that this will matter.

Hooked up 3 feet of 4" flex into 6" main and inserted 2 1/2" blast gate on opposite end. The 2 1/2" gate was included because I thought the suction might be strong enough to prevent sliding pieces across top. An open gate would allow release of the vacuum so pieces could be moved. Don't seem to need it, but it works great for a shop-vac hose to clean workbench and connect small sander, etc.

Drilled 3/8" holes on a 1" grid. The 4x4 blank I was refering to is just scrap fiberboard under the bit. When I want to use table for sanding, will have an insert drilled to match grid that I can insert. Only little pieces. Planning on a downdraft table with 6" duct.

That's about it. I'll report more as I get a chance to use it.

Kent
 
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