A power tool is an instrument that's actuated by an additional power source and mechanism apart from the solely manual labor used in combination with hand tools. The most common types of power tools use electric motors. Internal combustion engines and compressed surroundings are also commonly used. Other power sources include steam engines, direct burning of fuels and propellants, such as for example in powder-actuated equipment, or even natural power sources such as for example wind or moving water. Tools directly driven by pet power are not generally considered power tools.
Power tools are used in industry, in construction, in the garden, for housework tasks such as for example cooking, cleaning, and throughout the house for purposes of generating (fasteners), drilling, slicing, shaping, sanding, grinding, routing, polishing, painting, heating system and more.
Power tools are categorized as either electric power tools Stationary or portable, where portable means hand-held. Portable power tools have obvious advantages in mobility. Stationary power tools, however, frequently have advantages in quickness and accuracy. An average table saw, for instance, not only cuts faster than a regular hands saw, but the cuts are smoother, straighter, and more square than what is normally achievable with a hand-held power saw. Some stationary power tools can produce objects that cannot be manufactured in any other method. Lathes, for example, produce truly round objects.
Stationary power tools for metalworking are often called machine tools. The term machine tool isn't usually applied to stationary power equipment for woodworking, although 
such usage is sometimes heard, and in some cases, such as drill presses and bench grinders, exactly the same tool is used for both woodworking and metalworking.