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Caliper
Calipers or callipers are an instrument used to measure the linear dimensions of an object or hole; namely, the length, width, thickness, diameter or depth of an object or hole. The word "caliper" comes from a corrupt form of caliber. Many types of calipers permit reading out a measurement on a ruled scale, a dial, or an electronic digital display. A common association is to calipers using a sliding vernier scale. Some calipers can be as simple as a compass with inward or outward-facing points, but with no scale (measurement indication). The tips of the caliper are adjusted to fit across the points to be measured, and then kept at that span while moved to separate measuring device, such as a ruler. Calipers are used in many fields such as mechanical engineering, metalworking, forestry, woodworking, science and medicine. Terminology ''Caliper'' is the American spelling, while ''calliper'' (double "L") is the British spelling. A single tool might be referred to as a '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caliper Detail View
Calipers or callipers are an instrument used to Measurement, measure the linear dimensions of an object or hole; namely, the length, width, thickness, diameter or depth of an object or hole. The word "caliper" comes from a corrupt form of caliber. Many types of calipers permit reading out a measurement on a ruled scale ruler, scale, a dial (measurement), dial, or an electronic digital display. A common association is to calipers using a sliding vernier scale. Some calipers can be as simple as a compass (drafting), compass with inward or outward-facing points, but with no scale (measurement indication). The tips of the caliper are adjusted to fit across the points to be measured, and then kept at that span while moved to separate measuring device, such as a ruler. Calipers are used in many fields such as mechanical engineering, metalworking, forestry, woodworking, science and medicine. Terminology ''Caliper'' is the American and British spelling differences, American spellin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vernier Scale
A vernier scale ( ), named after Pierre Vernier, is a visual aid to take an accurate measurement reading between two graduation markings on a linear scale by using mechanical interpolation, which increases resolution and reduces measurement uncertainty by using vernier acuity. It may be found on many types of instrument measuring length or measuring angles, but in particular on a vernier caliper, which measures lengths of human-scale objects (including internal and external diameters). The vernier is a subsidiary scale replacing a single measured-value pointer, and has for instance ten divisions equal in distance to nine divisions on the main scale. The interpolated reading is obtained by observing which of the vernier scale graduations is coincident with a graduation on the main scale, which is easier to perceive than visual estimation between two points. Such an arrangement can go to a higher resolution by using a higher scale ratio, known as the vernier constant. A ver ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micrometer (device)
A micrometer, sometimes known as a micrometer screw gauge (MSG), is a device incorporating a calibrated screw for Accuracy and precision, accurate measurement of the size of components. It widely used in mechanical engineering, machining, metrology as well as most mechanical trades, along with other dimensional instruments such as Caliper#Dial caliper, dial, Caliper#Vernier caliper, vernier, and Caliper#Digital caliper, digital calipers. Micrometers are usually, but not always, in the form of calipers (opposing ends joined by a frame). The spindle is a very accurately machined screw and the object to be measured is placed between the spindle and the anvil. The spindle is moved by turning the ratchet knob or thimble until the object to be measured is lightly touched by both the spindle and the anvil. History The word ''micrometer'' is a classical compound, neoclassical coinage from and . According to the Webster's Dictionary#Merriam-Webster Collegiate Dictionary, ''Merriam-Web ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pierre Vernier
Pierre Vernier (; 19 August 1580 at Ornans, Franche-Comté (at that time ruled by the Spanish Habsburgs, now part of France) – 14 September 1637, same location) was a mathematician and instrument inventor. He was the inventor and eponym of the vernier scale used in measuring devices. Life He was born in Ornans, France, in 1580. He was taught science by his father. He became captain and castellan of the castle at Ornans, for the King of Spain. He was also later councillor and director general of economy in the County of Burgundy. In Brussels, in the year 1631, Vernier published his treatise ''La construction, l'usage, et les propriétés du quadrant nouveau de mathématique'', and dedicated it to the Infanta. In it, he described the ingenious device which now bears his name, the vernier scale. To a quadrant with a primary scale in half degrees Vernier proposed to attach a movable sector, thirty-one half degrees in length but divided into thirty equal parts (each pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metalworking
Metalworking is the process of shaping and reshaping metals in order 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 jewellery. 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 and including 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, cutt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compass (drafting)
A compass, also commonly known as a pair of compasses, is a technical drawing instrument that can be used for inscribing circles or Arc (geometry), arcs. As caliper#Divider caliper, dividers, it can also be used as a tool to mark out distances, in particular, on maps. Compasses can be used for mathematics, technical drawing, drafting, navigation and other purposes. Prior to computerization, compasses and other tools for manual drafting were often packaged as a set with interchangeable parts. By the mid-twentieth century, Technical drawing tool#Templates, circle templates supplemented the use of compasses. Today those facilities are more often provided by computer-aided design programs, so the physical tools serve mainly a didactic purpose in teaching geometry, technical drawing, etc. Construction and parts Compasses are usually made of metal or plastic, and consist of two "legs" connected by a hinge which can be adjusted to allow changing of the radius of the circle drawn. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American And British Spelling Differences
Despite the various English dialects spoken from country to country and within different regions of the same country, there are only slight regional variations in English orthography, the two most notable variations being British and American spelling. Many of the differences between American and British or Commonwealth English date back to a time before spelling standards were developed. For instance, some spellings seen as "American" today were once commonly used in Britain, and some spellings seen as "British" were once commonly used in the United States. A "British standard" began to emerge following the 1755 publication of Samuel Johnson's ''A Dictionary of the English Language'', and an "American standard" started following the work of Noah Webster and, in particular, his '' An American Dictionary of the English Language'', first published in 1828. Webster's efforts at spelling reform were effective in his native country, resulting in certain well-known patterns of sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wang Mang
Wang Mang (45 BCE6 October 23 CE), courtesy name Jujun, officially known as the Shijianguo Emperor (), was the founder and the only emperor of the short-lived Chinese Xin dynasty. He was originally an official and consort kin of the Han dynasty and later seized the throne in 9 CE. The Han dynasty was restored after his overthrow, and his rule marked the separation between the Western Han dynasty (before Xin) and Eastern Han dynasty (after Xin). Traditional Chinese historiography viewed Wang as a tyrant and usurper, while more recently, some historians have portrayed him as a visionary and selfless social reformer. During his reign, he abolished slavery and initiated a land redistribution program. Though a learned Confucian scholar who sought to implement the harmonious society he saw in the Chinese classics, his efforts ended in chaos. Wang Mang's late reign saw large-scale peasant rebellions, most notably the revolt of the Red Eyebrows. In October 23 CE, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chinese Era Name
Chinese era names, also known as reign mottos, were titles used by various Dynasties of China, Chinese dynasties and regimes in History of China#Imperial China, Imperial China for the purpose of regnal year, year identification and numbering. The first monarch to adopt era names was the Emperor Wu of Han in 140 BCE, and this system remained the official method of year identification and numbering until the establishment of the Republic of China (1912–1949), Republic of China in 1912 CE, when the era name system was superseded by the Republic of China calendar. Other polities in the Sinosphere—Korean era name, Korea, Vietnamese era name, Vietnam and Japanese era name, Japan—also adopted the concept of era name as a result of Chinese politico-cultural influence. Description Chinese era names were titles adopted for the purpose of identifying and numbering years in Imperial China. Era names originated as mottos or slogans chosen by the reigning List of Chinese monarchs, monarc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xin Dynasty
The Xin dynasty (; ), also known as Xin Mang () in Chinese historiography, was a short-lived Dynasties in Chinese history, Chinese imperial dynasty which lasted from 9 to 23 AD, established by the Han dynasty consort kin Wang Mang, who usurped the throne of the Emperor Ping of Han and the infant "crown prince" Ruzi Ying, Liu Ying. The Xin dynasty ruled for over a decade before it was overthrown by rebels. After Wang's death, the Han dynasty was restored by Emperor Guangwu of Han, Liu Xiu, a distant descendant of the Emperor Jing of Han; therefore, the Xin dynasty is often considered an interregnum of the Han, dividing it into the Western Han and the Eastern Han. Etymology Chinese dynasties were typically named after the fief of their founders, and this reading is consistent with Wang Mang's pre-imperial position as Marquess of Xin. In 1950, C.B. Sargent suggested that the name of the dynasty should be read as meaning "new", which J. J. L. Duyvendak rejected out of hand. Chauncey S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Encyclopædia Britannica 2006 Ultimate Reference Suite DVD
An encyclopedia is a reference work or compendium providing summaries of knowledge, either general or special, in a particular field or discipline. Encyclopedias are divided into articles or entries that are arranged alphabetically by article name or by thematic categories, or else are hyperlinked and searchable. Encyclopedia entries are longer and more detailed than those in most dictionaries. Generally speaking, encyclopedia articles focus on ''factual information'' concerning the subject named in the article's title; this is unlike dictionary entries, which focus on linguistic information about words, such as their etymology, meaning, pronunciation, use, and grammatical forms.Béjoint, Henri (2000)''Modern Lexicography'', pp. 30–31. Oxford University Press. Encyclopedias have existed for around 2,000 years and have evolved considerably during that time as regards language (written in a major international or a vernacular language), size (few or many volumes), intent ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ancient Rome
In modern historiography, ancient Rome is the Roman people, Roman civilisation from the founding of Rome, founding of the Italian city of Rome in the 8th century BC to the Fall of the Western Roman Empire, collapse of the Western Roman Empire in the 5th century AD. It encompasses the Roman Kingdom (753–509 BC), the Roman Republic (50927 BC), and the Roman Empire (27 BC476 AD) until the fall of the western empire. Ancient Rome began as an Italic peoples, Italic settlement, traditionally dated to 753 BC, beside the River Tiber in the Italian peninsula. The settlement grew into the city and polity of Rome, and came to control its neighbours through a combination of treaties and military strength. It eventually controlled the Italian Peninsula, assimilating the Greece, Greek culture of southern Italy (Magna Graecia) and the Etruscans, Etruscan culture, and then became the dominant power in the Mediterranean region and parts of Europe. At its hei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
