George Saridakis replies: I used the heaviest schedule PVC pipe “couplings” which are thicker than PVC pipe available with a semi-hard O-ring material I got from an industrial supply place. I glued the PVC to plywood, turned a groove for the O-ring and CA’ed that to the pipe.
Peter James replies: I have made vacuum chucking systems for eight or ten lathes. I used vacuum pumps by Thomas industries that came from oxygen concentrators and were purchased on eBay. The rotary connectors were made using two sealed ball bearings. I used laminated Baltic Birch plywood for the chucks to get the depth needed.
See my article in the Summer, 2013 issue of The Journal. It goes into detail on how to build the chucking system and sources of materials. Since I wrote the article, the price of the vacuum pumps has increased to about $85. Get a rebuilt unit, it is worth the little extra to have a known good working pump. Be sure not to get a pump used in the air conditioning/refrigeration industry as these are oil sealed and will pump out a fine oil mist as they are not designed for continuous running. For sealing gaskets, I am now using pieces of Yoga mat. It is a good closed cell foam. It is just about the right thickness, seals well and is readily available.