I have an idea of making a vacuum table / fixed clamp points combo like on the attached pictures. Can anyone advise if it is a good idea of making this type of design? I have made a prototype with shop vac opening on one side and the hold down power was not distributed evenly across the whole table so the idea is putting the opening in the middle. Bottom board would be MDF 18mm, top board MDF 10mm connected to a regular shop vac.
Overall not a bad design but you need to realize that shop vacs were not designed for such usage. You'll burn one up fairly quickly. They need a constant and fairly high air flow to keep the motor cool. You should be using a vacuum pump designed for this purpose instead.
Rick has a good point But it depends on the shop vac, if it is a dual stage type with separate fan for cooling it will be fine, most wet/dry types are like this. Another option is to buy a blower for a central vac system, these are dual stage and will keep cool even with no suction airflow. such as this one.. New Central Vac Vacuum Motor Will Fit Most Brands 5.7" 2-stage tangent | eBay
Just found this nice resource.. your vac board design looks ok, i would say you might want to add some shallow grooves connecting the holes or many more holes, the vac will only be as strong as the surface area of the exposed holes, and the static pressure you can generate. Total Guide to DIY CNC Router Vacuum Tables
None specific. In the US Harbor Freight is a good source but may require several pumps for a table that size. A shop dust collection system might also be a good option but you will probably need to provide a small amount of bypass air to keep it happy. The main thing is to look for something rated for continuous use as it will likely be running for hours at a time.
Thank you for the link. I was expecting that 10mm MDF is porous enough to hold through the material, is this not realistic? Currently I have made 8mm holes, it would be better to make much more smaller holes? Sorry guys for asking so much questions about one stinky vacuum table but it would be a pity to ruin one nice MDF board if it will be of no use. Regarding vacuum "generator", the first idea was to use this one: SHOP-VAC Micro 10 Hand Held Vacuum EU PLUG / Shop-Vac Wet/Dry Vacs I have the bigger one and it works nice for dust collection in combination with cyclone.
the MDF is only porous in that way if you take the skin off both sides, and even then the shopvac doesn't make the kind of static pressure you need for that to be very effective. if you do a grid on top about half way through, then it will take care of the dead zones you have as well, and increase the surface area of the vacuum.
MDF does work great if you have the right vacuum source, my old shop had a 10hp vacuum pump with a 100 gallon pump down vessel that allowed me to hold anything just by placing it on top of the mdf chamber.
