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pfulghum
08-31-2015, 04:02 PM
I used to own a big PRTAlpha for many years, but I had to sell it so I can move, and bought a desktop last year, but dust collection and vacuum table on this desktop have been a big challenge. I wanted to post my final results and then document the process on the way so others can learn from my mistakes.

First off, to use a vacuum table, the air must flow down through the table and exit back up through between the table and the rear support area. The Y carriage of the desktop design makes straight downdraft not possible

Here is the completed project.


.http://www.talkshopbot.com/forum/attachment.php?attachmentid=25913&stc=1



Here you can notice that I recessed the feet so that if the machine wanted to walk away it couldn't.

http://www.talkshopbot.com/forum/attachment.php?attachmentid=25914&stc=1


(I have no idea why I can't rotate my photos)

- Pat

pfulghum
08-31-2015, 04:22 PM
My vacuum is based on 1" PVC ... The largest size that was still small enough for the air to go under the table and up the back with interfering with spindle carriage without any loss in the Y axis.

I cut two 2 pieces of 3/4 inch (11 ply plywood from my favorite Orange colored store with the initials of H.D.) to size so that it would fit nicely within the desktop's cut area.

Before I removed the table existing table I let the shopbot drill very accurate circles to snuggly fit the 90 degree elbow fitting. If I recall correctly the holes where centered at 6, 9 and 19,9 to make sure that the future piping will not interfere with the mechanical pieces underneath. Measure once, cut twice.

NOTE: Most elbow fittings will have a smooth sidewall (with no lettering) that making it fit snuggly into a cutout with any play.

I aligned the holes then screwed the pieces together from the underside. Three coats of shellac on the top to seal it from the vacuum.

http://www.talkshopbot.com/forum/attachment.php?attachmentid=25916&stc=1http://www.talkshopbot.com/forum/attachment.php?attachmentid=25917&stc=1http://www.talkshopbot.com/forum/attachment.php?attachmentid=25918&stc=1

pfulghum
08-31-2015, 04:31 PM
After I trial fit, I noticed that the 24" span of plywood could use a bit a support across the middle. So I went back to my favorite HD store and got a piece of 2x2x1/8" aluminum angle and made a support across the front support of the shopbot.

I used the extruded aluminum as a straight edge and drilled and then tapped the shopbot support (just the what Shotbot did on the sides).

Note the cutout to not interfere with the lead screw.

http://www.talkshopbot.com/forum/attachment.php?attachmentid=25919&stc=1http://www.talkshopbot.com/forum/attachment.php?attachmentid=25920&stc=1http://www.talkshopbot.com/forum/attachment.php?attachmentid=25921&stc=1http://www.talkshopbot.com/forum/attachment.php?attachmentid=25922&stc=1


Stupid shopbot photo thing won't let me rotate the photos... sorry...

pfulghum
08-31-2015, 04:50 PM
Next I had to cut the PVC elbow to provide a nice tight "S" curve.
I needed to minimize the spacing between the elbows, but still allow enough height between the bottom of the table and the top of the rear support.

I sawed off about 5/16" on one side of both elbows. (only one side of elbow). Glue them together.

Here is a picture of a "safe" way to cutoff the elbows.... well... it was safe enough.

http://www.talkshopbot.com/forum/attachment.php?attachmentid=25925&stc=1http://www.talkshopbot.com/forum/attachment.php?attachmentid=25924&stc=1

pfulghum
08-31-2015, 04:53 PM
Now it is time to mount the table.
A simple trick is to put some bolts in the support angles and then place the board on top.
Give it a quick whack with your deadblow hammer and now you know where to drill the mounting holes.


http://www.talkshopbot.com/forum/attachment.php?attachmentid=25926&stc=1http://www.talkshopbot.com/forum/attachment.php?attachmentid=25927&stc=1

pfulghum
08-31-2015, 05:00 PM
More plumbing to complete the project.
Over the electronics and out to the left side to the Fein vacuum.
Give yourself a nice 2" PVC coupler and your fein hose will fit right in.

You will notice a tee with a threaded fitting. That is for a future Vacuum gauge, or to actually use my low volume high vacuum pump.


http://www.talkshopbot.com/forum/attachment.php?attachmentid=25933&stc=1http://www.talkshopbot.com/forum/attachment.php?attachmentid=25932&stc=1http://www.talkshopbot.com/forum/attachment.php?attachmentid=25931&stc=1

Brady Watson
08-31-2015, 06:43 PM
Pat,
In case you overlooked it - You might want to put a couple rubber couplings so that you can get the manifold apart to access the electronics. I install these on all systems to allow the pump or manifold to be removed for service and to dampen vibration from larger pumps.

-B