422 Modern Welding quickly. The rod oxidizes and causes the thicker plate to start oxidizing when the cutting oxygen is turned on. Figure 14-27 shows a welder cutting a thick section. Special cutting torches are produced that are capable of handling the much higher volumes and pressures of cutting oxygen required for cutting very thick metal. See Figure 14-28. With the proper equipment, extremely thick steel can be cut. See Figure 14-29. Be sure to read and carefully follow all manufacturer’s tables and safety charts prior to attempting this type of cutting operation. Cutting torches are most commonly used to cut straight lines, however, clean cuts can be made by skilled welders following any pattern or curvature. This is referred to as shape cutting. Shape cutting can be done free-hand, using a variety of special cutting attachments such as a circle cutting guide, or by setting up an automated cutting torch. 14.6.3 Cutting Chamfers (Bevels) Another important torch cutting operation is the cutting of chamfers for bevel and V-groove joints on the edges of steel plate prior to welding, as shown in Figure 14-30. Thicker pieces of steel must have the chamfered edge preparation so the weld penetrates through the thickness of the metal. Figure 14-26. Steps for starting a cut on thick metal. A—The correct oxyfuel gas cutting torch position for the starting cut. B—The required change in the torch position as the cut progresses. A B Figure 14-27. A skilled welder uses a cutting torch to make an accurate cut on 4″ (10.2cm) thick steel. (Victor, a division of Thermadyne Industries, Inc.) Figure 14-28. A—High-pressure cutting tip designed to accommodate the higher oxygen volume and pressure. B—The long torch body typically has feet to enable the welder to hold the torch steady while reaching and cutting. (ESAB Welding and Cutting Products) A B