Vacuum Chuck

I mentioned a while back that a friend of mine had given me a Vacuum Pump. My first goal for the pump was to build a vacuum chuck system for my lathe. This broke down into three parts; fittings and air filter for the vacuum pump, a rotary adaptor and the chucks.

Work on the vacuum pump went smoothly. I built a small cart on wheels to situate the pump on. The wheels make it very easy to move around my workshop. I attached the air filter and relief valve to the side of the cart. The relief valve allows me to release the vacuum or to reduce it. A vacuum gauge shows me how much of a vacuum I am pulling.

You can click on any of the images to see a larger version.

The next step was to build a rotary adapter. This part of the project did not go very smoothly unfortunately. I built three different rotary adapters. They were pretty easy to make and in theory should have worked. The first one I made out of some scrap cherry. I made the mistake of using a quick connect fitting, which proved to be to bulky. The adapter also leaked. The next two attempts were made from a block of resin I poured using a 2″ PVC pipe as a mold. I used a barbed hose fitting this time. They look very cool, but again both of them leaked. I’m not sure what I was doing wrong, I’m pretty sure that in all three attempts the leak was at the bearing. I was using double sealed bearings, but they still leaked. Here is a picture of my attempts.

Frustrated, I decided that I would simply buy a rotary adapter, and brought the Holdfast Vacuum Adapter. Strangely enough it worked right out of the box.

Building the vacuum chucks was fairly simple. I brought 4 different size PVC couplers, 1″, 2″, 3″ and 4″. From some hard maple I used my spindle tap and tapped a 1 1/4″ x 8 tpi thread in the block. I then threaded it on the lathe spindle and turned it round and true. Then I glued a piece of 3/4″ MDF to the block. Once the glue was dried I mounted it on the lathe, turned the MDF round and then cut a groove to accept the PVC coupler. Using 5 minute epoxy I glued the coupler to the MDF. Once the epoxy was dry I mounted it back on the lathe and trued up the PVC coupler. They just needed a light touch as they were running pretty true. While it was on the lathe I also drilled a hole through the center of the MDF to allow the air to escape. I smeared a thin coat of Titebond glue on all the surfaces of the MDF and when that dried coated it with lacquer to reduce the porosity of the material. Lastly I stuck some adhesive backed foam on the PVC coupler. I still plan on making another vacuum chuck using a 6″ PVC coupler.

Of course I couldn’t resist starting the vacuum pump and sticking all sorts of things to the vacuum chuck. It was amazing how strong it holds. There also seemed to be a wide range of vacuum that I was able to pull, depending on the size and material. I’m looking forward to using it on a bowl.

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