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Angle Grinder
An angle grinder, also known as a side grinder or disc grinder, is a handheld power tool used for grinding (abrasive cutting) and polishing. History The high-speed angle grinder was invented in 1954 by German company Ackermann + Schmitt ( FLEX-Elektrowerkzeuge GmbH) in Steinheim an der Murr. Naming In German, Dutch, Slovak, Czech, Polish, Croatian, Romanian, Hungarian, Bulgarian and Latvian, an angle grinder is colloquially called a "flex", and in Italy and in Spanish-speaking countries it is sometimes called "flexible". In Switzerland it is known as "Perles" from a popular brand of cutting tools. In Polish it is also known as "kątówka" or "gumówka" (= the rubber thing), which refers to the elasticity of certain types of disks. However they are never made out of true rubber due to fire hazard. In Russian, it is known as "болгарка" ("bolgarka") (literally "Bulgarian" of the feminine gender), since the first angle grinders in the USSR were Bulgarian made. Design ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diamond Blade
A diamond blade is a saw blade which has diamonds fixed on its edge for cutting hard or abrasive materials. There are many types of diamond blade, and they have many uses, including cutting stone, concrete, asphalt, bricks, coal balls, glass, and ceramics in the construction industry; cutting semiconductor materials in the semiconductor industry; and cutting gemstones, including diamonds, in the gem industry. Types Diamond blades are available in different shapes: * '' Circular diamond saw blades'' are the most widely used type of diamond blade. * A ''diamond gang saw blade'' is a long steel plate with diamond segments welded onto it. Normally, tens or hundreds of diamond gang saw blades are used together to saw raw stone blocks. * A ''diamond band saw blade'' is a flexible closed steel band with diamonds fixed (often by electroplating) on one edge of the band. Diamond blades designed for specific uses include marble, granite, concrete, asphalt, masonry, and gem-cutting blades ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BBC News
BBC News is an operational business division of the British Broadcasting Corporation (BBC) responsible for the gathering and broadcasting of news and current affairs in the UK and around the world. The department is the world's largest broadcast news organisation and generates about 120 hours of radio and television output each day, as well as online news coverage. The service has over 5,500 journalists working across its output including in 50 foreign news bureaus where more than 250 foreign correspondents are stationed. Deborah Turness has been the CEO of news and current affairs since September 2022. In 2019, it was reported in an Ofcom report that the BBC spent £136m on news during the period April 2018 to March 2019. BBC News' domestic, global and online news divisions are housed within the largest live newsroom in Europe, in Broadcasting House in central London. Parliamentary coverage is produced and broadcast from studios in London. Through BBC English Regions, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wheel Clamp
A wheel clamp, also known as wheel boot, parking boot, or Denver boot, is a device that is designed to prevent motor vehicles from being moved. In its most common form, it consists of a clamp that surrounds a vehicle wheel, designed to prevent removal of both itself and the wheel. In the United States, the device became known as a "Denver boot" after the city of Denver, Colorado, which was the first place in the country to employ them, mostly to force the payment of outstanding traffic ticket, parking tickets. While primarily associated with law enforcement and parking violations, a variety of wheel clamps are now available to consumers as theft deterrent devices for personal use as an alternative to the steering-wheel lock. Functions Wheel clamps have five main functions: * To punish unauthorised or illegal parking, in lieu of towing the offending vehicle; in these cases, police or property owners who place the clamp may charge a high "release fee" to remove it * To enforc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Accuracy And Precision
Accuracy and precision are two measures of ''observational error''. ''Accuracy'' is how close a given set of measurements (observations or readings) are to their ''true value''. ''Precision'' is how close the measurements are to each other. The International Organization for Standardization (ISO) defines a related measure: ''trueness'', "the closeness of agreement between the arithmetic mean of a large number of test results and the true or accepted reference value." While ''precision'' is a description of ''random errors'' (a measure of statistical variability), ''accuracy'' has two different definitions: # More commonly, a description of ''systematic errors'' (a measure of statistical bias of a given measure of central tendency, such as the mean). In this definition of "accuracy", the concept is independent of "precision", so a particular set of data can be said to be accurate, precise, both, or neither. This concept corresponds to ISO's ''trueness''. # A combination of both ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mandrel
A mandrel, mandril, or arbor is a tapered tool against which material can be forged, pressed, stretched or shaped (e.g., a ring mandrel - also called a triblet - used by jewellers to increase the diameter of a wedding ring), or a flanged or tapered or threaded bar that grips a workpiece to be machined in a lathe. A flanged mandrel is a parallel bar of a specific diameter with an integral flange towards one end, and threaded at the opposite end. Work is gripped between the flange and a nut on the thread. A tapered mandrel (often called a plain mandrel) has a taper of approximately 0.005 inches per foot and is designed to hold work by being driven into an accurate hole on the work, gripping the work by friction. A threaded mandrel may have a male or female thread, and work which has an opposing thread is screwed onto the mandrel. On a lathe, mandrels are commonly mounted between centres and driven by a lathe dog (typically flanged or tapered mandrels), but may also be gripped in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Revolutions Per Minute
Revolutions per minute (abbreviated rpm, RPM, rev/min, r/min, or r⋅min−1) is a unit of rotational speed (or rotational frequency) for rotating machines. One revolution per minute is equivalent to hertz. Standards ISO 80000-3:2019 defines a physical quantity called ''rotation'' (or ''number of revolutions''), dimensionless, whose instantaneous rate of change is called ''rotational frequency'' (or ''rate of rotation''), with units of reciprocal seconds (s−1). A related but distinct quantity for describing rotation is ''angular frequency'' (or ''angular speed'', the magnitude of angular velocity), for which the SI unit is the radian per second (rad/s). Although they have the same dimensions (reciprocal time) and base unit (s−1), the hertz (Hz) and radians per second (rad/s) are special names used to express two different but proportional ISQ quantities: frequency and angular frequency, respectively. The conversions between a frequency and an angular frequency ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pneumatics
Pneumatics (from Greek 'wind, breath') is the use of gas or pressurized air in mechanical systems. Pneumatic systems used in industry are commonly powered by compressed air or compressed inert gases. A centrally located and electrically-powered compressor powers cylinders, air motors, pneumatic actuators, and other pneumatic devices. A pneumatic system controlled through manual or automatic solenoid valves is selected when it provides a lower cost, more flexible, or safer alternative to electric motors, and hydraulic actuators. Pneumatics also has applications in dentistry, construction, mining, and other areas. History Although the early history of pneumatics is somewhat unclear, blowguns are often considered the earliest pneumatic device, being created independently by various indigenous groups around the world. Bellows are an early form of air compressor used primarily for smelting and forging. Ctesibius of Alexandria is often considered the father of pneum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Power Cord
A power cord, line cord, or mains cable is an electrical cable that temporarily connects an electrical appliance, appliance to the mains electricity supply via a wall socket or extension cord. The terms are generally used for cables using a AC power plugs and sockets, power plug to connect to a single-phase alternating current power source at the local line voltage (generally 100 to 240 volts, depending on the location). The terms power cable, mains lead, flex or kettle lead are also used. A lamp cord (also known as a zip cord) is a light-weight, ungrounded, single-insulated two-wire cord used for small loads such as a table or floor lamp. A cord set includes connectors molded to the cord at each end (see Appliance coupler). Cord sets are detachable from both the power supply and the electrical equipment, and consist of a flexible cord with electrical connectors at either end, one male, and one female. One end of the cord set is attached to a molded electrical plug; the other is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cordless
The term cordless is generally used to refer to electrical or electronic devices that are powered by a battery (electricity), battery or battery pack and can operate without a power cord or cable attached to an electrical outlet to provide mains power, allowing greater mobility. The term "cordless" should not be confused with the term "wireless", although it often is in common usage, possibly because some cordless devices (e.g., cordless telephones) are also wireless. The term "wireless" generally refers to devices that use some form of energy (e.g., radio waves, infrared, Ultrasound, ultrasonic, etc.) to transfer ''information'' or ''commands'' over a distance without the use of communication wires, regardless of whether the device gets its power from a power cord or a battery. The term "wikt:portable, portable" is an even more general term and, when referring to electrical and electronic devices, usually means devices which are totally self-contained (e.g., have built-in power su ... [...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] |
