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Reeding
Reeding is a technique wherein a number of narrow ridges called "reeds" are carved or milled into a surface. __NOTOC__ Numismatics In numismatics, reeded edges are often referred to as "ridged" or "grooved" (American usage), or "milled" (British usage). Some coins, such as United States quarters and dimes, 1 euro, Australian 5, 10, 20 cents, 1 and 2 dollars, as well many other current coins, have reeded edges. One reason for having reeded edges was to prevent counterfeiting. Some gold and silver coins were reeded to discourage clipping, i.e. scraping off the precious metals from the edge of the coin, to maintain its stated value in precious metal. This practice was made more difficult through the implementation of reeding by Isaac Newton in 1698, during his time as warden of the Royal Mint. Another benefit of certain coins having reeded edges is that it helps the visually impaired identify different coin denominations by sense of touch alone. This dual purpose of reeding is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluting (architecture)
Fluting in architecture consists of shallow grooves running along a surface. The term typically refers to the grooves (flutes) running vertically on a column shaft or a pilaster, but need not necessarily be restricted to those two applications. If the hollowing out of material meets in a point, the point (sharp ridge) is called an arris. If the raised ridge between two flutes is blunt, the ridge is a . Purpose Fluting promotes a play of light on a column which helps the column appear more perfectly round than a smooth column. As a strong vertical element it also has the visual effect of minimizing any horizontal joints. Greek architects viewed rhythm as an important design element. As such, fluting was often used on buildings and temples to increase the sense of rhythm. It may also be incorporated in columns to make them look thinner, lighter, and more elegant. There is debate as to whether fluting was originally used in imitation of ancient woodworking practices, mimickin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dime (United States Coin)
The dime, in United States usage, is a ten-cent coin, one tenth of a United States dollar, labeled formally as "one dime". The denomination was first authorized by the Coinage Act of 1792. The dime is the smallest in diameter and is the thinnest of all U.S. coins currently minted for circulation, being in diameter and in thickness. The obverse of the current dime depicts the profile of President Franklin D. Roosevelt and the reverse boasts an olive branch, a torch, and an oak branch, from left to right respectively. The word ''dime'' comes from the Old French ''disme'' ( Modern French dîme), meaning "tithe" or "tenth part", from the Latin ''decima ars'. The dime is currently the only United States coin in general circulation that is not denominated in terms of dollars or cents. , the dime cost 5.65 cents to produce. History The Coinage Act of 1792 established the dime (spelled "disme" in the legislation), cent, and mill as subdivisions of the dollar equal to , and dol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methods Of Coin Debasement
Coin debasement is the act of decreasing the amount of precious metal in a coin, while continuing to circulate it at face value. This was frequently done by governments in order to inflate the amount of currency in circulation; typically, some of the precious metal was replaced by a cheaper metal when the coin was minted. But when done by an individual, precious metal was physically removed from the coin, which could then be passed on at the original face value, leaving the debaser with a profit. Coin debasement was effected by several methods, including clipping (shaving metal from the coin's circumference) and sweating (shaking the coins in a bag and collecting the dust worn off). Until the mid-20th century, coins were often made of silver or (rarely) gold, which were quite soft and prone to wear. This meant coins naturally got lighter (and thus less valuable) as they aged, so coins that had lost a small amount of bullion would go unnoticed. Modern coins used as currency are ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molding (decorative)
Moulding (spelled molding in the United States), or coving (in United Kingdom, Australia), is a strip of material with various profiles used to cover transitions between surfaces or for decoration. It is traditionally made from solid milled wood or plaster, but may be of plastic or reformed wood. In classical architecture and sculpture, the moulding is often carved in marble or other stones. A "plain" moulding has right-angled upper and lower edges. A "sprung" moulding has upper and lower edges that bevel towards its rear, allowing mounting between two non-parallel planes (such as a wall and a ceiling), with an open space behind. Mouldings may be decorated with paterae as long, uninterrupted elements may be boring for eyes. Types Decorative mouldings have been made of wood, stone and cement. Recently mouldings have been made of extruded PVC and Expanded Polystyrene (EPS) as a core with a cement-based protective coating. Synthetic mouldings are a cost-effective alternative ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quarter (United States Coin)
The quarter, short for quarter dollar, is a United States coin worth 25 cents, one-quarter of a dollar. The coin sports the profile of George Washington on its obverse, and after 1998 its reverse design has changed frequently. It has been produced on and off since 1796 and consistently since 1831. It has a diameter of 0.955 inch (24.26 mm) and a thickness of 0.069 inch (1.75 mm). Its current version is composed of two layers of cupronickel (75% copper, 25% nickel) clad on a core of pure copper. With the cupronickel layers comprising 1/3 of total weight, the coin's overall composition is therefore 8.33% nickel, 91.67% copper. Its weight is 5.670 grams (0.1823 troy oz, or 0.2000 avoirdupois oz). Designs before 1932 The choice of a quarter-dollar as a denomination, as opposed to the or the 20-cent piece that is more common elsewhere; it originated with the practice of dividing Spanish milled dollars into eight wedge-shaped segments, which gave rise to the n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Milled Coinage
In numismatics, the term milled coinage (also known as machine-struck coinage) is used to describe coins which are produced by some form of machine, rather than by manually hammering coin blanks between two dies (hammered coinage) or casting coins from dies. Introduction Until 1550, coinage techniques used in European mints had not progressed from the hammered coinage of Ancient Greece. This was problematic because an increase in the supply of bullion from central Europe and America was overworking mints. That led to low quality coins which were easily forged or clipped, i.e. precious metal was shaved from the edges of the coins. In accordance with Gresham's law, the clipped and forged coins drove good coins out of circulation, depreciating the currency. Leonardo da Vinci's notebooks showed there was a better way and Donato Bramante, the architect who made the initial plans for St. Peter's Basilica, developed a screw press to make the lead bullae attached to Papal document ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
King George VI Hong Kong 50 Cents 1951 Security Edge
King is the title given to a male monarch in a variety of contexts. The female equivalent is queen, which title is also given to the consort of a king. *In the context of prehistory, antiquity and contemporary indigenous peoples, the title may refer to tribal kingship. Germanic kingship is cognate with Indo-European traditions of tribal rulership (c.f. Indic ''rājan'', Gothic ''reiks'', and Old Irish ''rí'', etc.). *In the context of classical antiquity, king may translate in Latin as '' rex'' and in Greek as '' archon'' or '' basileus''. *In classical European feudalism, the title of ''king'' as the ruler of a ''kingdom'' is understood to be the highest rank in the feudal order, potentially subject, at least nominally, only to an emperor (harking back to the client kings of the Roman Republic and Roman Empire). *In a modern context, the title may refer to the ruler of one of a number of modern monarchies (either absolute or constitutional). The title of ''king'' is us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metalworking
Metalworking is the process of shaping and reshaping metals to create useful objects, parts, assemblies, and large scale structures. As a term it covers a wide and diverse range of processes, skills, and tools for producing objects on every scale: from huge ships, buildings, and bridges down to precise engine parts and delicate jewelry. The historical roots of metalworking predate recorded history; its use spans cultures, civilizations and millennia. It has evolved from shaping soft, native metals like gold with simple hand tools, through the smelting of ores and hot forging of harder metals like iron, up to highly technical modern processes such as machining and welding. It has been used as an industry, a driver of trade, individual hobbies, and in the creation of art; it can be regarded as both a science and a craft. Modern metalworking processes, though diverse and specialized, can be categorized into one of three broad areas known as forming, cutting, or joining proc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Woodworking
Woodworking is the skill of making items from wood, and includes cabinet making (cabinetry and furniture), wood carving, joinery, carpentry, and woodturning. History Along with stone, clay and animal parts, wood was one of the first materials worked by early humans. Microwear analysis of the Mousterian stone tools used by the Neanderthals show that many were used to work wood. The development of civilization was closely tied to the development of increasingly greater degrees of skill in working these materials. Among early finds of wooden tools are the worked sticks from Kalambo Falls, Clacton-on-Sea and Lehringen. The spears from Schöningen (Germany) provide some of the first examples of wooden hunting gear. Flint tools were used for carving. Since Neolithic times, carved wooden vessels are known, for example, from the Linear Pottery culture wells at Kückhofen and Eythra. Examples of Bronze Age wood-carving include tree trunks worked into coffins from nor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Numismatics
Numismatics is the study or collection of currency, including coins, tokens, paper money, medals and related objects. Specialists, known as numismatists, are often characterized as students or collectors of coins, but the discipline also includes the broader study of money and other means of payment used to resolve debts and exchange goods. The earliest forms of money used by people are categorised by collectors as "Odd and Curious", but the use of other goods in barter exchange is excluded, even where used as a circulating currency (e.g., cigarettes or instant noodles in prison). As an example, the Kyrgyz people used horses as the principal currency unit, and gave small change in lambskins; the lambskins may be suitable for numismatic study, but the horses are not. Many objects have been used for centuries, such as cowry shells, precious metals, cocoa beans, large stones, and gems. Etymology First attested in English 1829, the word ''numismatics'' comes from the adjec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Architectural Elements
:''The following outline is an overview and topical guide to architecture:'' Architecture – the process and the product of designing and constructing buildings. Architectural works with a certain indefinable combination of design quality and external circumstances may become cultural symbols and / or be considered works of art. What ''type'' of thing is architecture? Architecture can be described as all of the following: * Academic discipline – focused study in one academic field or profession. A discipline incorporates expertise, people, projects, communities, challenges, studies, inquiry, and research areas that are strongly associated with the given discipline. * Buildings – buildings and similar structures, the product of architecture, are referred to as architecture. * One of the arts – as an art form, architecture is an outlet of human expression, that is usually influenced by culture and which in turn helps to change culture. Architecture is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spline (mechanical)
Splines are ridges or teeth on a drive shaft that matches with grooves in a mating piece and transfer torque to it, maintaining the angular correspondence between them. For instance, a gear mounted on a shaft might use a male spline on the shaft that matches the female spline on the gear. The splines on the pictured drive shaft match with the female splines in the center of the clutch plate, while the smooth tip of the axle is supported in the pilot bearing in the flywheel. An alternative to splines is a keyway and key, though splines provide a longer fatigue life, and can carry significantly greater torques for the size. Types There are several types of splines: ;Parallel key spline: where the sides of the equally spaced grooves are parallel in both directions, radial and axial. ;Involute spline: where the sides of the equally spaced grooves are involute, as with an involute gear, but not as tall. The curves increase strength by decreasing stress concentrations. ;Crowned s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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