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Knee (construction)
In woodworking, a knee is a natural or cut, curved piece of wood. Knees, sometimes called ships knees, are a common form of bracing in boat building and occasionally in timber framing. A rafter, knee rafter in carpentry is a bent rafter used to gain head room in an attic. Strength characteristics Wood is a highly anisotropic material (its strength varies considerably with the direction of applied force, i.e. parallel, radial, or tangential to the grain). Because wood is strongest when loaded in tension or compression along the grain, the best knees are those in which the wood grain follows the bend. For a knee with relatively little bend, it may be possible to cut the knee out of a single straight-grained board and still achieve sufficient strength. However, with increasing bend this method becomes problematic since more and more of the knee is aligned across the grain and is therefore considerably weaker. A knee laid out this way might easily snap in two under hand pressure alon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hackmatack
''Larix laricina'', commonly known as the tamarack, hackmatack, eastern larch, black larch, red larch, or American larch, is a species of larch native to Canada, from eastern Yukon and Inuvik, Northwest Territories east to Newfoundland (island), Newfoundland, and also south into the upper northeastern United States from Minnesota to Cranesville Swamp, West Virginia; there is also an isolated population in central Alaska. The word ''akemantak'' is an Algonquian languages, Algonquian name for the species and means "wood used for snowshoes". Description ''Larix laricina'' is a small to medium-size Boreal forest, boreal coniferous and deciduous tree reaching tall, with a trunk up to diameter. Tamaracks and larches (''Larix'' species) are deciduous conifers. The bark is tight and flaky, pink, but under flaking bark it can appear reddish. The leaf, leaves are needle-like, short, light blue-green, turning bright yellow before they fall in the autumn, leaving the pale pinkish-brown ... [...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] |
Steam Bending
Steam bending is a woodworking technique where wood is exposed to steam to make it pliable. Heat and moisture from steam can soften wood fibres enough so they can be bent and stretched, and when cooled down they will hold their new shape. In modern times, steam bending is usually done with a steam box to make it bend around a former. The moulding process is typically done by clamping wooden strips to a positive form, with the strips of wood often reinforced on the outside with a metal band to prevent blowout. The method has been used in the manufacturing of a diverse range of products, including wooden boat building where it is used in the shaping of hull's ribs and lap boards, the production of traditional wooden lacrosse sticks, musical instruments such as the violin, the manufacture of wooden furniture such as the Windsor chair and much of Michael Thonet's and Alvar Aalto's work. Steam bending is a traditional process steeped in history. It was once a vital practice, paramoun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ship Building
Shipbuilding is the construction of ships and other floating vessels. It normally takes place in a specialized facility known as a shipyard. Shipbuilders, also called shipwrights, follow a specialized occupation that traces its roots to before recorded history. Shipbuilding and ship repairs, both commercial and military, are referred to as "naval engineering". The construction of boats is a similar activity called boat building. The dismantling of ships is called ship breaking. History Pre-history The earliest known depictions (including paintings and models) of shallow-water sailing boats is from the 6th to 5th millennium BC of the Ubaid period of Mesopotamia. They were made from bundled reeds coated in bitumen and had bipod masts. They sailed in shallow coastal waters of the Persian Gulf. 4th millennium BC Ancient Egypt Evidence from Ancient Egypt shows that the early Egyptians knew how to assemble planks of wood into a ship hull as early as 3100 BC. Egyptian potte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boat Building
Boat building is the design and construction of boats and their systems. This includes at a minimum a hull, with propulsion, mechanical, navigation, safety and other systems as a craft requires. Construction materials and methods Wood Wood is the traditional boat building material used for hull and spar construction. It is buoyant, widely available and easily worked. It is a popular material for small boats (of e.g. length; such as dinghies and sailboats). Its abrasion resistance varies according to the hardness and density of the wood and it can deteriorate if fresh water or marine organisms are allowed to penetrate the wood. Woods such as Teak, Totara and some cedars have natural chemicals which prevent rot whereas other woods, such as Pinus radiata, will rot very quickly. The hull of a wooden boat usually consists of planking fastened to frames and a keel. Keel and frames are traditionally made of hardwoods such as oak while planking can be oak but is more often softw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hardwoods
Hardwood is wood from dicot trees. These are usually found in broad-leaved temperate and tropical forests. In temperate and boreal latitudes they are mostly deciduous, but in tropics and subtropics mostly evergreen. Hardwood (which comes from angiosperm trees) contrasts with softwood (which is from gymnosperm trees). Characteristics Hardwoods are produced by angiosperm trees that reproduce by flowers, and have broad leaves. Many species are deciduous. Those of temperate regions lose their leaves every autumn as temperatures fall and are dormant in the winter, but those of tropical regions may shed their leaves in response to seasonal or sporadic periods of drought. Hardwood from deciduous species, such as oak, normally shows annual growth rings, but these may be absent in some tropical hardwoods. Hardwoods have a more complex structure than softwoods and are often much slower growing as a result. The dominant feature separating "hardwoods" from softwoods is the presence of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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