Introduction to Power Tools
Power sources and grounding
Power tools are classified by power source: electric (corded and cordless), pneumatic, hydraulic, and fuel-powered (gasoline). Each source has its own hazards - shock and cord damage for electric, whipping hoses and air injection for pneumatic, fluid injection and high pressure for hydraulic, and carbon monoxide for fuel-powered tools used indoors. Corded tools with three-prong plugs must be used with grounded receptacles; removing or bending the ground pin is never acceptable. On construction sites, temporary power must be GFCI protected. Match the tool's voltage to the supply, and use a cord gauge heavy enough for the run - longer runs need heavier gauge (lower number) to prevent overheating.
Safe operating rules
Read the manual, keep guards in place, and disconnect the power source before changing blades, bits, or accessories. Clamp the work; never hold it in your hand. Keep hands clear of the cut line, let the blade reach full speed before contact, and do not force a tool - forcing causes kickback and burned motors. Carry a corded tool by its body, not by the cord, and keep cords clear of the cut and out of walkways. Wear eye protection, hearing protection, and dust protection as the task requires, and tie back loose clothing and hair around rotating parts.
Traps
The exam likes damaged cords, missing guards, wrong blades, and using a tool in a wet location. A damaged or modified tool is out of service - report it.
Rule of thumb
If you have to force it, something is wrong: check the blade, the material, and the feed direction before pushing harder.