Abstract: The invention is directed to improved centrifugal rotary electric furnaces which are used for the heating and or fusion of minerals, such as quartz, and other materials having a high melting point. The furnace includes a generally cylindrical furnace shell and a decreasing diameter stepped end member attached to each end of the shell which is intended to more closely conform the end of the furnace to the shape of fused ingot or melted charge formed inside the furnace, while still providing a sufficient depth of unmelted charge between the fused or melted material and the end member to insulate the end member from excessive heat and the warpage and other damage caused thereby.