I've been researching a lot into making a vacuum table lately,,, and haven't really decided on anything for certain yet... but I don''t have much to spend on one, so a massive super sucking motor is not an option. I have a 4 x 8 machine.
Fein Vac? Imperial motor? Shop vac? Air compressor motor? Some other motor that I can scrounge up cheap? The options seem endless - any input would be appreciated. Basically, I know I'm not going to get an incredibly performing setup on the cheap, but I'm not necessarily looking for it. I don't mind also screwing the sheets down, tabs, and using clamps around the edge. But, if I can minimize some of that, and get some extra help on larger size pieces being cut out, that would be great. Also though, I'm hoping that it will help keep slightly bowed sheets flat. I know it won't pull a ton of warp out, but if I have only a little bit of a bow in a sheet, if it pulls even a little of it out, that would be great.
Also though, in my current bed, I have 1/4-20 T nuts underneath, on 4" centers. I use them all the time, and love them. I would hate to give them up - they're so handy for small pieces, jigs, and for clamping the entire perimiter of a sheet. If I can use those around the edge of sheets, or for smaller pieces, and a vacuum to help in the middle, that would seem ideal. Has anyone made a vacuum table which also has T-nuts? I'm curious how you would go about it, and if you could then just let the vacuum suck up through the T-nut holes, and cover the holes you're not using. Any ideas or examples? I'll keep researching, but I'm hoping someone here can help point me in the right direction. Thanks,
It's cheap to try something crude but effective, admittedly I did this on a smaller scale.
I started with a continuous surface spoil board--MDO plywood, no T nuts. I installed a PVC shower drain in the spoil board and connected it to my Fein shop vac. The perimeter gasket and inside support pieces were cut from LPDM rubber roofing (flat spoil board, no grooves at all). It all went together in an afternoon.
This works great for pieces at least 2' square. At 1' square I need to slow the router down and use reduced depth as there isn't enough holding force. This takes a shop vac with plenty of volume--a little HVAC vacuum pump would take the pressure a lot lower, but would not be able to keep up with the leaks. My Fein vac only provides about 1/3 atmosphere vacuum according to specs.
Try it, you will be up immediately and see if you really want to use the T nuts. For me, not having to screw the work down somehow is a big time saver.
Two details:
I connected my shop vac hose to the PVC by adding a layer of EPDM to the inside diameter of the PVC. The hose end is tapered, this thickness made a match.
Watch the EPDM and avoid seams, where it gets a little thicker and would make a leak area.
If you have a good size air compressor you might want to consider using a venturi vacuum generator. Exotic Wood Veneer, Vacuum Press Systems, Veneering Tools and Veneering Supplies This site has a lot of vacuum clamping equipment including the vacuum generators. You could build a nice system that monitors the vac pressures and cycles on and off to maintain the desired vacuum. As far as a vac table that also has the T-nuts, I think I've seen them on the internet but cant recall at the moment. Google is your friend.
DIY Vacuum Table, with T-nuts/Inserts???
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