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Unformatted text preview: TC 9-524 Chapter 3 PORTABLE MACHINE TOOLS The portable machine tools identified and described in this Portable machine tools are powered by self-contained chapter are intended for use by maintenance personnel in a electric motors or compressed air (pneumatic) from an outside shop or field environment. These lightweight, transportable source. They are classified as either cutting took (straight and machine tools, can quickly and easily be moved to the angle hand drills, metal sawing machines, and metal cutting workplace to accomplish machining operations. The accuracy shears) or finishing tools (sanders, grinders, and polishers). of work performed by portable machine tools is dependent upon the user’s skill and experience. SAFETY PRECAUTIONS GENERAL Portable machine tools require special safety precautions while being used. These are in addition to those safety precautions described in Chapter 1. PNEUMATIC AND ELECTRIC TOOL SAFETY Here are some safety precautions to follow : Never use electric equipment (such as drills, sanders, and saws) in wet or damp conditions. Properly ground all electric tools prior to use. Do not use electric tools near flammable liquids or gases. Inspect all pneumatic hose lines and connections prior to use. Keep constant watch on air pressure to stay within specified lim its. Keep all equipment in proper working order, and use the equipment according to the manufacturer’s instructions. Remove chuck keys from drills prior to use. Hold tools firm ly and maintain good balance. Secure the work in a holding device, not in your hands. Wear eye protection while operating these machines. Ensure that all lock buttons or switches are off before plugging the machine tool into the power source. Never leave a portable pneumatic hammer with a chisel, star drill, rivet set, or other tool in its nozzle. ELECTRIC EXTENSION CORDS Use the right wire gage for the length of the cord. As the length of the extension cord increases, heavier gage wire must be used. Lengthening extension cords by connecting several small gage cords together causes a serious drop in voltage. This results in the cord overheating. Extension cords that overheat will bum away the insulation, creating a potential electric shock hazard and fire hazard. See Table 3-1, Appendix A , for proper gage and length of extension cords. 3-1 TC 9-524 PORTABLE DRILLS PURPOSE AND TYPES The portable drill is a hand-supported, power-driven machine tool that rotates twist drills, reamers, counterbores, and sim ilar cutting tools. The portable drill may be electrically powered by means of an internal electric motor (Figure 3-1) or may be pneumatically powered (Figure 3-2). Portable drills are rated by the maximum size hole that can be drilled in steel without overtaxing the motor or drill....
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This note was uploaded on 10/26/2010 for the course ENGINEERIN MECH221 taught by Professor Wetton during the Spring '10 term at UBC.
- Spring '10