Hello Charley; do you have any images/photos/videos of this vac table setup you are describing ? Curious also if this is usable for sanding and how you handle the dust collection.
Thx Paul
Here are the Rockler Vacuum pods.
https://www.rockler.com/rockler-vacuum-clamp-pod-kit
I just screw them down on my workbench wherever a part of what I'm working on will completely cover the pod or pods. I have 4 of the Rockler pods. Then you just plug the hose between them and connect a vacuum pump with an air filter attached to keep saw dust out of the pump. Turn the pump on and drop your part onto the pods. I had an old refrigeration service vacuum pump that I was using, but recently bought a similar new vacuum pump from Harbor Freight. If you have no leaks, a vacuum under your part will pull it down tight. It will take considerable force to pull it free, or you can just turn off the vacuum pump and wait. Air will leak in and back through the vacuum pump, and the part will be free and easy to lift off.
You can use thick plastic sheet or Baltic Birch to make your own vacuum chucks in any size and shape that you want. Get some closed cell Weather stripping peel and stick foam and lay it out in any shape that you need, the larger the lazy circle, the better for holding force. When there is no air below your work 14.7 psi of atmosphere will be holding your work down. The larger the vacuum area within the foam circle, the tighter the vacuum and the atmospheric pressure will hold the part down.
I made a couple of vacuum chucks from Baltic Birch plywood and cut a groove in them to hold a large "O' ring for the seal. These worked, but were a bit tough to make and get a good seal. The closed cell foam is much easier to use, but the two ends must be joined with no gap. I overlap the ends and then cut through both with a razor blade, then massage the two ends together, removing the excess pieces.
Start with the pods from Rockler, then once you understand how they work, try making some on your own. The vacuum pumps don't do well if there are any leaks, so your pods, piping, and even your work piece needs to fit well so there are no leaks. When you make your own, you will need to drill some blind holes that intersect, for the air passages. This will become more obvious once you see the Rockler pods.
I don't have any photos handy on this computer, but did post a photo of the plywood pod that I made with the "O" ring. It was about 1 1/2 years ago. Here is the link
https://www.routerforums.com/tools-woodworking/117865-rockler-vacuum-chuck.html There are a bunch of Youtube videos for vacuum clamping, many for lathe work, but some for clamping to a work bench. SA search for "Vacuum Clamp" on Youtube will bring them up. Remember, the larger the vacuum chuck, the better it will hold because of that 14.7 psi of atmospheric pressure pushing toward the vacuum.
Charley
