I'm normally a reader and not a poster but I do have a little experience with home made vacuum tables that I don't mind sharing. I'm not exactly sure where I saw the original design that mine is fashioned from but it seems to work really well! It's made from 1 inch 6061. It's base is 6" x 3.5". It's working surface is 5" x 3.5". It has 9 horizontal (Y) channels and 9 Vertical (X) channels. Each channel is 1/8 x 1/8 with chamfered edges. The gasket material is 1/8 x 5/32 leaving 1/32 above table level. There is a single 1/8 hole in the center of the table that provides vacuum to all channels. I don't have any details about the vacuum pressures. I just use a small vac/compressor without any problems. I use it for small engraving jobs or when I need to fly cut several pieces of stock when I work on multiple projects of the same piece.
This link will show you a page with one Quicktime movie at the top showing my first design in action. Click on the photo and see a page showing 8 short Quicktime movies of how I made the vacuum table.
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