Today I started a babington burner. It makes clean fire from all kinds of oils, including waste oil. Instead of a clog prone and ineffective nozzle a sphere is used. Oil drops onto and flows over the outside. Compressed air is blown through the back and out a small hole near the tip. When the oil hits that hole the air sprays it into an amazingly fine fog. It looks like smoke, not mist and it burns very well. Since only air flows through the hole it stays clean. The hemi-sphere is being generated by a milling cutter. It moved in an arc in the horizontal plane that started on the pole and ended at the equator. The rod was turned 40 times while the cutter followed an arc. It is as if a spiral were stretched into a hemi-sphere.