I bought a vac-clamp to see how it would work with my X2 mill. I have a few issues with it, and decided that if I could cut a decent venturi, I'd build my own vac table. I have the venturi done, and it works as well as the venturi in the vac-clamp. It needs less air than the vac-clamp, so my compressor will run less. I don't know about suction CFM, but it seems to be capable of the job.
About the venturi:
I machined the "catch" off of two brass 1/4" NPT quick-connect air hose couplings. I used a piece of C360 brass for the jet. The couplings and jet are press-fit together, with a bit of 603 Loctite for good measure. I did this on my lathe. I adjusted the depth of the jet for best suction. I used the vac-clamp's table to test the vacuum of my venturi, blocking the vac-clamp's exit hole. Pulling off .2" acrylic, I could tell no difference in the vac-clamp venturi versus mine.
Using the quick-connect couplings made this really easy to do.
The sketch isn't quite to scale, but you get the idea.
Enjoy,
Paul |