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Dutchman (repair)
A dutchman, or in some uses graving piece, is a matching piece of good material used to replace a relatively small damaged area that has been cut out of a larger item, to avoid having to replace the entire item; or, any of various techniques for accomplishing such a repair. In some cases, the meaning has been extended to include small pieces that are inserted between units of a larger structure as a planned part of the construction process, rather than as an ad hoc repair. The term is used in woodworking, masonry, railroading, boatbuilding, theater, and other fields. Uses Woodworking In construction and woodworking, a dutchman can refer to an inset wood patch used to repair wood. Typically a square inset is cut into the damaged area and a new piece of wood is glued into the inset. Masonry In stone masonry, a Dutchman is an inset selectively replacing only the fault in a stone with new stone material, usually matching adjacent material as closely as possible. Shipbuilding In shi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Track (rail Transport)
A railway track (British English and UIC terminology) or railroad track (American English), also known as permanent way or simply track, is the structure on a railway or railroad consisting of the rails, fasteners, railroad ties (sleepers, British English) and ballast (or slab track), plus the underlying subgrade. It enables trains to move by providing a dependable surface for their wheels to roll upon. Early tracks were constructed with wooden or cast iron rails, and wooden or stone sleepers; since the 1870s, rails have almost universally been made from steel. Historical development The first railway in Britain was the Wollaton Wagonway, built in 1603 between Wollaton and Strelley in Nottinghamshire. It used wooden rails and was the first of around 50 wooden-railed tramways built over the next 164 years. These early wooden tramways typically used rails of oak or beech, attached to wooden sleepers with iron or wooden nails. Gravel or small stones were packed around the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fishplate
A fishplate joins two lengths of track A fishplate, splice bar or joint bar is a metal connecting plate used to bolt the ends of two rails into a continuous track. The name is derived from ''fish'', a wooden reinforcement of a "built-up" ship's mast that helped round out its desired profile. The top and bottom faces taper inwards along their short dimensions to create an even alignment between the two rails when the fish plate is wedged into place by tightening its bolts during installation. In rail transport modelling, a fishplate is often a small copper or nickel silver plate that slips onto both rails to provide the functions of maintaining alignment and electrical continuity. History The device was invented by William Bridges Adams in May 1842, because of his dissatisfaction with the scarf joints and other systems of joining rails then in use. He noted that to form the scarf joint the rail was halved in thickness at its ends, where the stress was greatest. It was firs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermite
Thermite () is a pyrotechnic composition of metal powder and metal oxide. When ignited by heat or chemical reaction, thermite undergoes an exothermic reduction-oxidation (redox) reaction. Most varieties are not explosive, but can create brief bursts of heat and high temperature in a small area. Its form of action is similar to that of other fuel-oxidizer mixtures, such as black powder. Thermites have diverse compositions. Fuels include aluminum, magnesium, titanium, zinc, silicon, and boron. Aluminum is common because of its high boiling point and low cost. Oxidizers include bismuth(III) oxide, boron(III) oxide, silicon(IV) oxide, chromium(III) oxide, manganese(IV) oxide, iron(III) oxide, iron(II,III) oxide, copper(II) oxide, and lead(II,IV) oxide. The reaction, also called the Goldschmidt process, is used for thermite welding, often used to join railway tracks. Thermites have also been used in metal refining, disabling munitions, and in incendiary weapons. Some thermite-like ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
