Replies

1. 
   DonStephan | Jan 10, 2006 03:10am | #1

   Try to find specs on some commercial downdraft tables. The one flyer I saw suggested a table this size would need a monster motor and impeller to be effective at catching all the dust.

1. 
   Ronaway | Jan 10, 2006 06:05am | #2

   Don I have been trying to find specs on comercial tables but to no avail. They seem to be
   kinda stingy with their proprietary info, which one would expect. I think I read the same flyer
   that you refer to, and came to the same conclusion. The only thing that is left to do is to
   construct some experimental sanding tops and use my 3hp cyclone as a blower source to
   develop my own data concerning top size, hole configuration, and baffle taper angles. I have also starting playing with the idea of some configuration that would create a curtain of air traveling across the top of the table and being sucked back down on the other side. The biggest drawback that I see with all the tables is the need to clean filters on a regular basis in order to maintain consistent performance results. I have been spoiled by my cyclone and long intervals between filter cleanings.Ron

   Edited 1/9/2006 10:07 pm ET by Ronaway

2. 
   forestgirl | Jan 12, 2006 03:55am | #3

   Darn, if you were closer than Georgia I'd sell you mine.  Barring that possibility, I could send you some design info on it.  I bought it at an estate sale [the woodworker who everything, and sometimes 3 or 4 of them -- he had very good taste but not much willpower, evidently].  It's about 5' wide x 30" deep, probably 45-48" high.  Big squirrel cage blower in it, frame at the top for filters, 3-speed switch.  He built it himself, and even chamfered the sides of all the holes in the top, a big, big job.

   I'll be interested in any engineering info you find, as I want to close off some of the vast space inside this thing and put in some storage -- drawers probably. 

   forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
   Another proud member of the  "I Rocked With ToolDoc Club" .... :>) 

1. 
   Ronaway | Jan 12, 2006 08:51pm | #4

   And why would you be so willing to sell me your table, is it the frequency of filter cleaning?
   I have done considerable more research since I started the original post. I have come to
   several conclusions. (1) I do not want a table with an integrated blower. I don't believe that
   there is a good want to put a seperator in the confines of the table, and other than
   that I think a lot of filter cleaning would be required.(2) I don't think that it is feasible to construct a table of the size that I originally stated and have it work very well so I now think that a 30 x 60 inch table would be a more resonable size. (3) Trying to make a table that matches the model that Bill Pentz describes would be a tall task. I am not going to be trying to catch shavings fly off the bit of a router with this table, just gathering dust from my sanding operations. (4) considering that one would always have a work piece on the table covering some of the holes, I believe one could attain pretty good collection on a bigger table than Bill describes, and if a large area of the table was not in use it could be covered in order to increase effectiveness in the area that was being utilized. When larger work pieces are put on the table they effectively cover more holes and that should increased the amount air drawn thru the holes around the perimeter of the work piece. If that proves to be the case then I am thinking I may want to put larger holes around the perimeter of the table.(5) I hope to be able to power the table with a 6" duct run from a 3hp cyclone collector.Edited 1/12/2006 12:53 pm ET by RonawayEdited 1/12/2006 12:54 pm ET by Ronaway

   Edited 1/12/2006 12:55 pm ET by Ronaway

1. 
   forestgirl | Jan 13, 2006 09:16pm | #5

   "And why would you be so willing to sell me your table...?"  When I'm crunched for space, it's the only item that is eligible to remove from the mix!  I'm not certain I want to sell it, but the thought has crossed my mind.  It's close enough to the height of the table saw that it could double as an outfeed table, just need to rearrange the furniture.

   Sounds like space isn't a problem in your shop.  Good luck, hope you find some helpful input on the design.

   Hmmmm, if you've decided to move away from an internal blower, and instead use the dust collector, seems like you could simply make an enlarged version of the benchtop sanding tables that are getting fairly common these days.  One with legs and storage underneath even.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)Another proud member of the  "I Rocked With ToolDoc Club" .... :>) 

1. 
   Ronaway | Jan 13, 2006 10:48pm | #6

   I am actually going to be moving into a larger 24 x 60 space sometime this year. This will be my opportunity to have permanent versions of several work tables that are presently knockdown versions that store when not in use. The idea of a downdraft top with just a 6"duct running from the bottom would allow for the rest of the space under the table to be used as enclosed storage. I believe in enclosed storage in a woodworking shop. It makes the work tables much stronger and you don't have to touch everything you own when it's time to
   do what I call a "Back to Ground Zero" clean up. Definition of a "Back to Ground Zero" clean up: When you clean and reorganize your shop back to way it was when you first moved in.Ron"If you are too open minded your brains will fall out"

1. 
   forestgirl | Jan 18, 2006 10:18am | #7

   Please post a description (and pictures?) when you get it done.  Look forward to seeing what you come up with!forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)Another proud member of the  "I Rocked With ToolDoc Club" .... :>)