Chapter 14 Oxyfuel Gas Cutting 429 ● Flames should be adjusted so each torch produces an identical cut. ● Distance of the torch tip from the metal being cut must be carefully adjusted to obtain the best results. This adjusting is done by means of a graduated scale on the torch body, and a vernier gear mechanism (measuring device that permits fi ne adjustment), to raise and/or lower the torch. In addition to properly setting up and adjusting the machine, the operator must periodically inspect and perform maintenance on its critical parts, such as cutting tips. Most welding schools have a designated cutting area that has a motorized carriage for students to use in practicing how to properly set up and make adjustments to the cutting outfi t. See Figure 14-39. A magnetic tracer with a steel pattern can be used as a cutting torch guiding device. The tracer, driven by a small, adjustable motor, rotates and follows the pattern. Cutting torches, or torches, are normally mechanically attached to the tracer mechanism. As the tracer moves, the torches move in the same pattern to cut the metal. The speed of cutting is determined by the speed of rotation of the pattern tracer. The vari- able-speed motor on the tracer must be manually set. It allows the tracer and the cutting torches to move at the correct speed for the thickness of metal being cut. 14.10 Safety in Oxyfuel Gas Cutting In order for oxyfuel gas cutting to be safely performed, proper procedures must be followed. Dangers can be greatly reduced through the careful Figure 14-39. This welding school has a well-ventilated oxyfuel gas cutting area complete with motorized carriages for student practice.