Abstract: A side edge surface of a web plate is trimmed by or machined after feeding a milling cutter into the side edge surface of the web plate, which cutter has on its outer peripheral surface cutting edges at a predetermined angle with respect to its rotary axis, and driving the milling cutter in rotation. The rotary axis of the milling cutter is a plane which is kept parallel to a desired machined surface of the side edge surface of the web plate, and the angle formed between the cutting edge of the milling cutter and the side edge surface of the web plate is limited to within 55 degrees to 125 degrees.

Abstract: A side edge surface of a web plate is trimmed or machined after by feeding a milling cutter into the side edge surface of the web plate, which cutter has on its outer peripheral surface cutting edges at a predetermined angle with respect to its rotary axis, and driving the milling cutter in rotation. The rotary axis of the milling cutter is inclined in a plane which is kept parallel to a desired machined surface of the side edge surface of the web plate, and the angle formed between the cutting edge of the milling cutter and the side edge surface of the web plate is limited to within 55 degrees to 125 degrees.

Abstract: Waste material heated in the bottom of a thermal decomposition furnace is vaporized to create gas flow upwardly within the furnace. Cooling means located to have the upwardly flowing gas pass thereacross operates to control the temperature of the gas leaving the furnace through the upper end thereof so that gaseous product having a boiling point above the boiling point induced by the cooling means will condense and fall within the furnace onto tray means located below the cooling means and adapted to receive therein condensed liquid from the cooling means. The tray means include orifice means for enabling upwardly flowing gas to come into contact with the liquid received in the tray means, and downflow tubes for causing liquid within the tray means to flow downwardly to the bottom of the furnace into contact with heating means. Gas flowing upwardly from the heating means passes through the orifice means and into contact with the liquid in the tray means.