A chainsaw (or chain saw) is a portable mechanical saw, powered by electricity, compression air, hydraulics power, or most commonly a two-stroke engine. It is used for many things related to cutting trees. It can also be used to fell snags and assist in cutting firebreaks in wildland fire suppression, and to harvest firewood. Special chainsaws are used for cutting concrete.
A chainsaw has several parts, including:
- Engine — usually a two-stroke gasoline (petrol) internal combustion engine, usually with a cylinder volume of 30-120 cm3 or electric motor.
- Drive mechanism — typically a clutch and sprocket.
- Guide bar — a long bar with a round end of wear-resistant alloy steel usually 16 to 36 inches in length. An edge slot guides the cutting chain.
- Cutting chain — Usually each segment in this chain (which is constructed from riveted metal sections similar to a bicycle chain, but without rollers) features small sharp blades called teeth. The bottom of each link features a small metal finger called a "drive link" which locates the chain on the bar, helps to carry lubrication oil around the bar, and engages with the engine's drive sprocket inside the body of the saw.
As chainsaw carving has become more popular, the makers of chansaws are making special short, narrow-tipped bars for carving. These are called "quarter tipped," "nickel tipped" or "dime tipped" bars, based on the size of the round tip.