A chainsaw is a portable handheld power saw that cuts with a set of teeth attached to a rotating chain driven along a guide bar. Modern chainsaws are typically gasoline or electric and are used in activities such as tree felling, limbing, bucking, pruning, cutting firebreaks in wildland fire suppression, harvesting of firewood, for use in chainsaw art and chainsaw mills, for cutting concrete, and cutting ice.
source.image: Sanya Tsvay
This chain saw has the following features: It has a 16-inch (40.6-cm) cutting bar. The chain runs in a groove around this bar, and on the chain are the cutting teeth. It has an air-cooled two-stroke gasoline engine. A chainsaw comprises an engine, a drive mechanism, a guide bar, a cutting chain, a tensioning mechanism, and safety features.
Various safety practices and working techniques are used with chainsaws. The chain is driven by a centrifugal clutch. When the engine is idling, the clutch is disengaged. When the engine speeds up, the centrifugal plates in the clutch spin outward to engage the clutch, and the chain begins running. Chainsaw engines are traditionally either a two-stroke single-cylinder gasoline (petrol) internal combustion engine (usually with a cylinder volume of 30 to 120 cm3). In a petrol chainsaw, fuel is generally supplied to the engine by a carburetor at the intake.
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Usually, each segment in a chain (which is constructed from riveted metal sections similar to a bicycle chain, but without rollers) features small, sharp, cutting teeth. Each tooth takes the form of a folded tab of chromium-plated steel with a sharp angular or curved corner and two beveled cutting edges, one on the top plate and one on the side plate. Left-handed and right-handed teeth are alternated in the chain. Chains are made in varying pitch and gauge; the pitch of a chain is defined as half of the length spanned by any three consecutive rivets (e.g., 8 mm, 0.325 inch), while the gauge is the thickness of the drive link where it fits into the guide bar (e.g., 1.5 mm, 0.05 inch).
