400 Section 6 Oxyfuel Gas Processes Copyright Goodheart-Willcox Co., Inc. 3. Select the correct cutting tip. Use a tip with 4–6 preheating orifices, if possible. Install the tip in the torch. 4. Turn on the station and set the correct pressures. Light the torch and adjust for neutral preheating flames. 5. Place your left hand on the table. Rest the torch in the left hand. As the cut progresses, slide the torch through your left hand. This prevents the torch from shaking. 6. For a right-handed welder, start the cut at the right and progress toward your left. For a left- handed welder, start the cut at the left and progress toward your right. 7. Hold the tip 5°–20° from vertical. The centerline of the tip should be aligned with the line to be cut. The preheating flames should be about 1/16″– 1/8″ (1.5 mm–3.0 mm) above the metal. 8. Squeeze the oxygen cutting valve when the metal turns an orange-red color (1500°F/816°C). The cut will begin. 9. Progress at a constant rate to complete the cut. 10. Repeat the process for the next four lines. Exercise 26-2 Manually Cutting Straight Edges— Using Steel Angle 1. Obtain a piece of mild steel to cut that measures at least 1/4″ × 6″ × 6″ (6 mm × 150 mm × 150 mm). 2. Obtain a piece of angle iron that measures at least 1″ × 1″ × 7″ (25 mm × 25 mm × 175 mm). Also, obtain a clamp or clamps to attach the angle iron. 3. Using soapstone or chalk, mark out five lines on the surface of the plate to be cut 1″ (25 mm) apart. Refer to the following figure. 4. Select the correct cutting tip. Use a tip with 4–6 preheating orifices, if possible. See Figure 24-28. Install the tip in the torch. 5. Lay one leg of the angle flat, with other leg perpendicular to the base metal. Position the angle just off the line to be cut to allow for the tip thickness. Clamp the angle firmly in place. 6. Turn on the station and set the correct pressures. Light the torch and adjust for neutral preheating flames. 7. Hold the tip 5°–15° from vertical. The centerline of the tip should be aligned with the line to be cut. The preheating flames should be about 1/16″– 1/8″ (1.5 mm–3.0 mm) above the metal. 8. Preheat the edge of the metal until the metal turns an orange-red color (1500°F/816°C). Squeeze the oxygen cutting valve, and the cut will begin. 9. Slide the cutting torch tip along the steel angle and progress at a constant rate to complete the cut. 10. Repeat the process for the next four lines. 6″ (150 mm) 1″ (25 mm) 1″ (25 mm) 1″ (25 mm) 1″ (25 mm) 1″ (25 mm) 1″ (25 mm) 6″ (150 mm)