Here is the way I made my simple vacuum chuck. At the bottom of this page is a material list and suppliers. Since I’m using scrap pieces left over from a different project, I pick out pieces that approximate in size. Also, I have made this chuck using MDF with equal success. The most important thing to consider here is that the base has no voids. The larger piece is the faceplate and measures about 7″. The smaller piece is a support plate for the bolt and is about 4″. 4″ x 8tpi, your lathe may be different, so you may need a different sized nut. 8″ , so I used a chisel to cut the notches for the bolt to fit. This probably made for a more secure and better fit. Using epoxy, I glued up the three pieces and let sit over night to cure. The next day I round over the support plate and the face plate.
I’m careful to make sure the outer edge of the recess is the same size as the outside of the coupler. On the inside, I remove extra material so there is some room for the epoxy. Next, I cut the recess for the bearing. I like a tight fit and make the recess as deep as the bearing is thick. Since each lathe’s headstock is different, you’ll have to determine the proper length that you need to cut the lamp rod. I eyeball it by holding the rod next to the lathe, with one end past the plate we just made and the other end past the hand wheel. Remember, it is easier to have it to long and cut a little more off than to try to glue a piece back on.
I chuck up the lamp rod into my pin jaws. With the lathe spinning at a slow speed, I file away a section until the rod not only fits inside the sealed bearing, but is also a little longer then the thickness of the bearing. I want a tight fit, almost a compression fit. So I take my time to make sure it is right. This took me about two full minutes to get the dimension that I need. The following day I insert the lamp rod and flare the end so it stays in place. I don’t use any epoxy here. The last thing I want is for the bearing to be locked in place.
Then I epoxied the PVC coupler in place and again let it sit overnight. Here is the finished vacuum chuck along with the foam sheet cut into a donut. The last vacuum chuck I made I would glue the foam to the chuck. I decided to try to keep it loose just to see how it works. I use the foam sheet as a gasket between the stock and the chuck to aid in a good seal. With the lamb rod though the headstock, I connect the tube which supplies the vacuum. Here is the chuck mounted on the lathe. Spinning test piece at 897 RPMs.
For a test bowl, I decided to start off small to work any kinks out that may arrive. Notice the little hole in the center, this hole was made by the live center when I was first turning a tenon. Now I will use this same hole to help me align the bowl on the vacuum chuck. All lined up, tool rest in place and ready to turn. In no time at all I cleaned off the tenon, so far everything is running smoothly. Here I am decorating the bottom. Here I have a 18″ Natural Edge Bowl all set and ready to turn.