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Saw Chain
The saw chain, or cutting chain, is a key component of a chainsaw. It consists of steel links held together by rivets, and superficially resembles the bicycle-style roller chain, although it is closer in design to a leaf chain. Its key differences are sharp cutting teeth on the outside of the chain loop, and flat drive links on the inside, to retain the chain on the saw's bar and allow propulsion by the engine or motor. Saw chains (and chainsaws generally) are used for cutting wood. This may be for harvesting trees for pulp or timber, for tree surgery, or for processing firewood. Whether for hand-held chainsaws, mechanical timber harvesters or chain mortisers, the saw chain has undergone dramatic development since its invention. Modern chains designed for high power, high-speed sawing applications will vastly outperform older designs, while allowing a far greater degree of safety and reliability in use. Principles of saw chain operation Saw chains operate by being propelled aro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chainsaw
A chainsaw (or chain saw) is a portable gasoline-, electric-, or battery-powered saw that cuts with a set of teeth attached to a rotating chain driven along a guide bar. It is used in activities such as tree felling, limbing, bucking, pruning, cutting firebreaks in wildland fire suppression, and harvesting of firewood. Chainsaws with specially designed bar-and-chain combinations have been developed as tools for use in chainsaw art and chainsaw mills. Specialized chainsaws are used for cutting concrete during construction developments. Chainsaws are sometimes used for cutting ice; for example, ice sculpture and winter swimming in Finland. History In surgery The origin of chain saws in surgery is debated. A "flexible saw", consisting of a fine serrated link chain held between two wooden handles, was pioneered in the late 18th century (c. 1783–1785) by two Scottish doctors, John Aitken and James Jeffray, for symphysiotomy and excision of diseased bone, respectively. It was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Softwood
file:Pinus sylvestris wood ray section 1 beentree.jpg, Scots Pine, a typical and well-known softwood Softwood is wood from gymnosperm trees such as conifers. The term is opposed to hardwood, which is the wood from angiosperm trees. The main differences between hardwoods and softwoods is that the structure of hardwoods lack resin canals, whereas softwoods lack pores (though not all softwoods have resin canals). Characteristics Softwood is wood from gymnosperm trees such as pines and spruces. Softwoods are not necessarily softer than hardwoods. In both groups there is an enormous variation in actual wood hardness, the range of density in hardwoods completely including that of softwoods. Some hardwoods (e.g. balsa) are softer than most softwoods, while the hardest hardwoods are much harder than any softwood. The woods of longleaf pine, Douglas fir, and Taxus, yew are much harder in the mechanical sense than several hardwoods. Softwoods are generally most used by the construction ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chainsaws
A chainsaw (or chain saw) is a portable gasoline-, electric-, or battery-powered saw that cuts with a set of teeth attached to a rotating chain driven along a guide bar. It is used in activities such as tree felling, limbing, bucking, pruning, cutting firebreaks in wildland fire suppression, and harvesting of firewood. Chainsaws with specially designed bar-and-chain combinations have been developed as tools for use in chainsaw art and chainsaw mills. Specialized chainsaws are used for cutting concrete during construction developments. Chainsaws are sometimes used for cutting ice; for example, ice sculpture and winter swimming in Finland. History In surgery The origin of chain saws in surgery is debated. A "flexible saw", consisting of a fine serrated link chain held between two wooden handles, was pioneered in the late 18th century (c. 1783–1785) by two Scottish doctors, John Aitken and James Jeffray, for symphysiotomy and excision of diseased bone, respectively. It was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chainsaw Safety Clothing
Safety practices generally recommend that chainsaw users wear protective clothing, also known as personal protective equipment or PPE, while operating chainsaws. There is general agreement worldwide on what clothing is suitable, but local jurisdictions have specific rules and recommendations. Clothing Helmet The helmet offers some protection for the user's head against impact by the cutter bar of the chainsaw should a 'kickback' occur. Kickback is when the running chainsaw jumps up unexpectedly out of the cut, thus endangering the saw operator. Helmet protection can only be successful if the chain brake has been operated to stop the saw chain, since a chain running at full speed can easily cut into the helmet. The helmet, and its eye protection guard, also protect against impacts from small falling or flying objects, such as dead twigs and branches from a tree being felled. Exposure to the sun causes the plastic of the helmet to weaken over time, so it is recommended that a h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chainsaw Safety Features
This article is about risk control methods specific to chainsaws and chainsaw operations. Chainsaws incorporate numerous safety features common to many engine-driven power tools. Manufacturers have invented numerous design features to improve safety. Some features have become ''de facto'' standards, and others are legal requirements in particular jurisdictions. Best practice dictates that an operator should inspect the saw before starting work and only operate the saw if all the safety features are properly functional. Additional safety features are a significant commercial advantage to chainsaw producers. Companies continue to develop new features over time. Most chainsaw safety features are focused on the kickback problem, and seek to either avoid it (chain and bar design), or to reduce the risk of injury should it occur ( chain brakes). In addition to the safety features built into the chainsaw, operators should also wear specific chainsaw safety clothing. Most older saws ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bicycle Chain
A bicycle chain is a roller chain that transfers power from the pedals to the drive-wheel of a bicycle, thus propelling it. Most bicycle chains are made from plain carbon or alloy steel, but some are nickel-plated to prevent rust, or simply for aesthetics. History Obsolete chain designs previously used on bicycles included the block chain, the skip-link chain, and the Simpson lever chain. The first chains were of a simple, bushing-less design. These had inherent reliability problems and a bit more friction (and mechanical efficiency losses) than modern chains. With these limitations in mind, the Nevoigt brothers, of the German Diamant Bicycle Company, designed the roller chain in 1898, which uses bushings. More recently, the "bushingless roller chain" design has superseded the bushed chain. This design incorporates the bearing surface of the bushing into the inner side plate, with each plate creating half of the bushing. This reduces the number of parts needed to assemble ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Timber Framing
Timber framing (german: Holzfachwerk) and "post-and-beam" construction are traditional methods of building with heavy timbers, creating structures using squared-off and carefully fitted and joined timbers with joints secured by large wooden pegs. If the structural frame of load-bearing timber is left exposed on the exterior of the building it may be referred to as half-timbered, and in many cases the infill between timbers will be used for decorative effect. The country most known for this kind of architecture is Germany, where timber-framed houses are spread all over the country. The method comes from working directly from logs and trees rather than pre-cut dimensional lumber. Hewing this with broadaxes, adzes, and draw knives and using hand-powered braces and augers (brace and bit) and other woodworking tools, artisans or framers could gradually assemble a building. Since this building method has been used for thousands of years in many parts of the world, many styles ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mortice And Tenon
A mortise and tenon (occasionally mortice and tenon) joint connects two pieces of wood or other material. Woodworkers around the world have used it for thousands of years to join pieces of wood, mainly when the adjoining pieces connect at right angles. Mortise and tenon joints are strong and stable joints that can be used in many projects. They furnish a strong outcome and connect by either gluing or locking into place. The mortise and tenon joint also gives an attractive look. One drawback to this joint is the difficulty in making it because of the precise measuring and tight cutting required. In its most basic form, a mortise and tenon joint is both simple and strong. There are many variations of this type of joint, and the basic mortise and tenon has two components: #the mortise hole, and #the tenon tongue. The tenon, formed on the end of a member generally referred to as a rail, fits into a square or rectangular hole cut into the other, corresponding member. The tenon is cu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chain Mortiser
A mortiser or morticer is a specialized woodworking machine used to cut square or rectangular holes in a piece of lumber (timber), such as a mortise in a mortise and tenon joint. Square chisel mortiser The square chisel mortiser (also called ''hollow chisel mortiser''), similar to a drill press in many respects, combines the cutting of a four-sided chisel with the action of a drill bit in the center. The bit clears out most of the material to be removed, and the chisel ensures the edges are straight and clean. This device was invented in 1874 by Robert and Ralph Greenlee (founders of the Greenlee Company). The first square chisel lever mortisers were purely manual and relied on the operator pulling down on a large lever to push the chisel through the timber. An improvement was to place a rotating cylindrical auger inside a hollow chisel. This helps to clear chips up the centre of the chisel. As electric power became easily available, the auger developed as a drill bit and becam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chainsaw Mill
A chainsaw mill or PortaMill or Alaskan mill or Alaskan sawmill or Logosol sawmill is a type of sawmill incorporating a chainsaw, that is used by one or two operators to mill logs into lumber for use in furniture, construction and other uses. Description The mill attachment consists of a pair of guide rails which are attached to the bar of the chainsaw. The rails ride for the first cut on a plank or on a metal ladder which is screwed to the log (but not so tightly that the guide is pulled out of plane), and then on the previously cut surface of the log, and guide the chainsaw blade through the log at a consistent depth so that planks of a chosen thickness are cut. The distance between the rails and the bar determines this thickness and it can be adjusted by moving the rails along a post at each end of the mill attachment. During use it is important that the rails extend out past the ends of the log so the cut has support the entire time. Small mills use a single chainsaw and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tungsten Carbide
Tungsten carbide (chemical formula: WC) is a chemical compound (specifically, a carbide) containing equal parts of tungsten and carbon atoms. In its most basic form, tungsten carbide is a fine gray powder, but it can be pressed and formed into shapes through sintering for use in industrial machinery, cutting tools, chisels, abrasives, armor-piercing shells and jewelry. Tungsten carbide is approximately twice as stiff as steel, with a Young's modulus of approximately 530–700 GPa, and is double the density of steel—nearly midway between that of lead and gold. It is comparable with corundum (α-) in hardness and can be polished and finished only with abrasives of superior hardness such as cubic boron nitride and diamond powder, wheels and compounds. Naming Historically referred to as Wolfram, ''Wolf Rahm'', wolframite ore was then later carburized and cemented with a binder creating a composite now called "tungsten carbide". Tungsten is Swedish for "heavy stone". Col ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steel
Steel is an alloy made up of iron with added carbon to improve its strength and fracture resistance compared to other forms of iron. Many other elements may be present or added. Stainless steels that are corrosion- and oxidation-resistant typically need an additional 11% chromium. Because of its high tensile strength and low cost, steel is used in buildings, infrastructure, tools, ships, trains, cars, machines, electrical appliances, weapons, and rockets. Iron is the base metal of steel. Depending on the temperature, it can take two crystalline forms (allotropic forms): body-centred cubic and face-centred cubic. The interaction of the allotropes of iron with the alloying elements, primarily carbon, gives steel and cast iron their range of unique properties. In pure iron, the crystal structure has relatively little resistance to the iron atoms slipping past one another, and so pure iron is quite ductile, or soft and easily formed. In steel, small amounts of carbon, other ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
