A Chainsaw (or Chain Saw) Is a Portable Mechanical Saw

A chainsaw (or chain saw) is a portable mechanical saw, powered by electricity, compressed air, hydraulic power, or most commonly a two-stroke engine. It is used in activities such as tree felling, limbing, bucking, pruning, by tree surgeons to fell trees and remove branches and foliage, to fell snags and assist in cutting firebreaks in wildland fire suppression, and to harvest firewood. Chainsaws with specially designed bar and chain combinations have been developed as tools for use in chainsaw art. Specialist chainsaws are used for cutting concrete. Construction A chainsaw consists of several parts. Engine — almost always a two-stroke gasoline (petrol) internal combustion engine, usually with a cylinder volume of 30-120 cm3 or electric motor. Drive mechanism — typically a centrifugal clutch and sprocket. Guide bar — an elongated bar with a round end of wear-resistant alloy steel typically 16 to 36 inches in length. An edge slot guides the cutting chain. Specialized loop-style bars, called brush bows, were also used at one time for bucking logs and clearing brush, although they are now rarely encountered due to increased hazards of operation. 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. Each tooth takes the form of a folded tab of chromium plate steel with a sharp angular or curved corner and two cutting edges on the top plate and side plate. Left-handed and right-handed teeth are alternated in the chain. Chains come 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., 0.325 inch), while the gauge is the thickness of drive link where it fits into the guide bar (e.g., 0.05 inch). Conventional "full complement" chain has one tooth per drive link. Built into each tooth is a depth gauge or "raker" which rides ahead of the tooth and limits the depth of cut, typically to around 0.025". Depth gauges are critical to safe chain operation. If left too high they will cause very slow cutting, if filed too low they will make the saw dangerous and hard to control. The underside of each link features a small metal finger called a "drive link" which locates the chain on the bar, helps to carry lubricating oil around the bar, and engages with the engine's drive sprocket inside the body of the saw. The engine drives the chain around the track by a centrifugal clutch, engaging the chain under power, but allowing it to stop as the engine idles. Dramatic improvements, chainsaw safety devices and overall design have taken place since the chainsaw's invention, saving many lives and preventing countless serious injuries. These include chainbrake systems, better chain design and anti-vibration systems. As chainsaw carving has become more popular, chainsaw manufacturers 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. Echo sponsors a carving series, as well as carvers such as former Runaways singer Cherie Currie. RedMax specifically built the G3200 CV chainsaw for carving applications. Source: en.wikipedia.org