Homemade Vacuum clamp

[Wes Grass]

Very slick.

4x4" @ 12 psi is 192 lbs. Pretty hard to pull off, but depending on the part and fixture materials, keeping it from sliding around could be a problem. A spiral flute generates a little lifting force, but not enough to pull the workpiece up. But not much problem sliding it around, so some sort of 'keys' to fix it in place are a requirement.

[Michael Burnside]

A vacuum table is a different animal than a fixture and requires a different kind of source for vacuum. It's also not a good setup for small parts because...gravity can't help much with very limited surface area. I mentioned this in my original reply to this thread.

Agreed. I have one on my CNC as well, runs at 15A and 240V. It works great but for small pieces you have to cover up the MDF area with plexiglass or other non-porous material. I use it for larger parts and sheet goods but for small parts it's just a lot of overkill to use it. In that circumstance, I prefer my "MFT dog hole" spoilboard with a few t-track channels that is indexed when I place it down on my Phenolic bed. As the name implies, it has spacing compatible with Festool so I use a few MFT jigs/squares and a lot of TSO products (dogs and dog stops). I find a couple of small clamps to hold down is sufficient (barely needed if using a downcut bit) and the dogs/dog stops prevent everything from slipping.

[Bruce Wrenn]

Couple of thoughts. For gasket material, use the "O" ring from a five gallon paint buckets, and tire patching cement to join ends. Venturi used in most commercial small vacuum units is Air-Vac's AVR093H ($39.99) Bill Hylton's book, "Router Magic," has a section devoted to vacuum jigs, and their construction. Many years back, Shop Notes did an article on vacuum jigs. To make individual pads for vacuum block, make one and then use it with vacuum to hold others for routing on router table.