Long ago in the nineteen eighties there was a monthly news letter called the Independent Glass Blower published by David Gruenig. In one of the issues a ring tool was discussed. It seemed like such a good idea that I had to make this tool.
The ring tool is used like a bottomless block, but only after the glass has cooled off a bit. The idea is to get your art marvered into a glass cylinder and round the end. Set a jack line into the cylinder to determine the size of the marble. Heat the glass back up and use the ring tool like a block, waxing it regularly like you would a jack blade. If it starts to squeak try flipping it over because the wax has run to the bottom side, or dunk it in water and re-wax it. Be sure to rock the ring tool over the top of the marble to remove any blocking lines left from the tool. Reheat and jack on the neck of the marble and block with the ring tool. Repeat this process until the neck is small enough to be finished, fire polish one last time and knock off. At this point the marble can be torched and the neck melted in or annealed and cold worked later
Our ring tools come in size 0 through six, and will make perfect spheres from 1.25" marbles to 3.5" paperweights.