Unit 3
PORTABLE MACHINE TOOLS

The portable machine tools identified and described in this chapter are intended for use by maintenance personnel in a shop or field environment. These lightweight, transportable machine tools, can quickly and easily be moved to the workplace to accomplish machining operations. The accuracy of work performed by portable machine tools is dependent upon the user’s skill and experience.

Portable machine tools are powered by self-contained electric motors or compressed air (pneumatic) from an outside source. They are classified as either cutting took (straight and angle hand drills, metal sawing machines, and metal cutting shears) or finishing tools (sanders, grinders, and polishers).

3-1 SAFETY PRECAUTIONS

Portable machine tools require special safety precautions while being used.

PNEUMATIC AND ELECTRIC TOOL SAFETY

Here are some safety precautions to follow:

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 for proper gage and length of extension cords.

Table 3-1. Proper wire gages for extension cords.