Vacuum Clamping

So, I’ve heard of, and read about, vacuum clamping, so I figured I’d give it a try. I’m working on a router jig for the second cross design and really don’t want to make clamps, or buy a pattern bit with the ball bearing below the cutter instead of above. With that, I took a piece of MDF, small rectangle, and drilled a hole for a male quick release air fitting, then a smaller hole all the way through. Teflon tape on the fitting, spin it in the hole, chuck it to my Harbor Freight AC vacuum pump turn it on and slap it on top of the router table. Even without a gasket, I could tell there was some vacuum.

Next, I took an oil filter o-ring, from the wife’s Saturn wagon filter (No, not the one on the car, this one is extra) and placed it between my MDF pattern and the router table top. STUCK! With that success, I stuck a piece of 3/4 oak ply to the MDF pattern and tried it on the router table, with a 1/2" diameter pattern bit. Not too bad. I think that the oak ply allows enough leakage that it slipped a bit.

Dug through the stuff drawer and found some foam tape gonna try this out. Anybody else tried vacuum clamping?