1.
Soldering
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Soldering, is a process in which two or more items are joined together by melting and putting a filler metal into the joint, the filler metal having a lower melting point than the adjoining metal. Soldering differs from welding in that soldering does not involve melting the work pieces, in brazing, the filler metal melts at a higher temperature, but the work piece metal does not melt. In the past, nearly all solders contained lead, but environmental and health concerns have increasingly dictated use of alloys for electronics. There is evidence that soldering was employed as early as 5000 years ago in Mesopotamia, soldering and brazing are thought to have originated very early in the history of metal-working, probably before 4000 BC. Sumerian swords from ~3000 BC were assembled using hard soldering, soldering was historically used to make jewelry items, cooking ware and tools, as well as other uses such as in assembling stained glass. Soldering is used in plumbing, electronics, and metalwork from flashing to jewelry, jewelry components, machine tools and some refrigeration and plumbing components are often assembled and repaired by the higher temperature silver soldering process. Small mechanical parts are often soldered or brazed as well, soldering is also used to join lead came and copper foil in stained glass work. Electronic soldering connects electrical wiring and electronic components to printed circuit boards, soldering filler materials are available in many different alloys for differing applications. In electronics assembly, the alloy of 63% tin and 37% lead has been the alloy of choice. Other alloys are used for plumbing, mechanical assembly, and other applications, a eutectic formulation has advantages when applied to soldering, the liquidus and solidus temperatures are the same, so there is no plastic phase, and it has the lowest possible melting point. Having the lowest possible melting point minimizes heat stress on electronic components during soldering, and, having no plastic phase allows for quicker wetting as the solder heats up, and quicker setup as the solder cools. A non-eutectic formulation must remain still as the temperature drops through the liquidus and solidus temperatures, any movement during the plastic phase may result in cracks, resulting in an unreliable joint. Common solder formulations based on tin and lead are listed below and they are also suggested anywhere young children may come into contact with, or for outdoor use where rain and other precipitation may wash the lead into the groundwater. Unfortunately, most lead-free solders are not eutectic formulations, melting at around 250 °C, alloying silver with other metals changes the melting point, adhesion and wetting characteristics, and tensile strength. Of all the brazing alloys, silver solders have the greatest strength, specialty alloys are available with properties such as higher strength, the ability to solder aluminum, better electrical conductivity, and higher corrosion resistance. The purpose of flux is to facilitate the soldering process, one of the obstacles to a successful solder joint is an impurity at the site of the joint, for example, dirt, oil or oxidation. The impurities can be removed by mechanical cleaning or by chemical means and this effect is accelerated as the soldering temperatures increase and can completely prevent the solder from joining to the workpiece. One of the earliest forms of flux was charcoal, which acts as a reducing agent, some fluxes go beyond the simple prevention of oxidation and also provide some form of chemical cleaning
2.
Solder
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Solder is a fusible metal alloy used to create a permanent bond between metal workpieces. The word solder comes from the Middle English word soudur, via Old French solduree and soulder, from the Latin solidare, meaning to make solid. In fact, solder must be melted in order to adhere to and connect the pieces together, whenever possible, the solder should also be resistant to oxidative and corrosive effects that would degrade the joint over time. Solder that is intended for use in making connections between electronic components also usually has favorable electrical characteristics. Soft solder typically has a melting point range of 90 to 450 °C, and is used in electronics, plumbing. Manual soldering uses an iron or soldering gun. Alloys that melt between 180 and 190 °C are the most commonly used, soldering performed using alloys with a melting point above 450 °C is called hard soldering, silver soldering, or brazing. In specific proportions, some alloys can become eutectic — that is, non-eutectic alloys have markedly different solidus and liquidus temperatures, and within that range they exist as a paste of solid particles in a melt of the lower-melting phase. In electrical work, if the joint is disturbed in the pasty state before it has solidified totally, for electrical and electronics work, solder wire is available in a range of thicknesses for hand-soldering, and with cores containing flux. It is also available as a paste or as a preformed foil shaped to match the workpiece, alloys of lead and tin were commonly used in the past, and are still available, they are particularly convenient for hand-soldering. Lead-free solders have been increasing in use due to regulatory requirements plus the health and they are almost exclusively used today in consumer electronics. Plumbers often use bars of solder, much thicker than the used for electrical applications. Jewelers often use solder in thin sheets, which cut into snippets. In the US, manufacturers may receive tax benefits by reducing the use of lead-based solder, lead-free solders in commercial use may contain tin, copper, silver, bismuth, indium, zinc, antimony, and traces of other metals. Most lead-free replacements for conventional 60/40 and 63/37 Sn-Pb solder have melting points from 5 to 20 °C higher and it may be desirable to use minor modification of the solder pots used in wave-soldering, to reduce maintenance cost due to increased tin-scavenging of high-tin solder. Lead-free solder may be desirable for critical applications, such as aerospace and medical projects. Tin-Silver-Copper solders are used by two-thirds of Japanese manufacturers for reflow and wave soldering, tin-based solders readily dissolve gold, forming brittle intermetallics, for Sn-Pb alloys the critical concentration of gold to embrittle the joint is about 4%. Indium-rich solders are more suitable for soldering thicker gold layer as the rate of gold in indium is much slower
3.
Pyrography
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Pyrography or pyrogravure is the art of decorating wood or other materials with burn marks resulting from the controlled application of a heated object such as a poker. It is also known as pokerwork or wood burning, the term means writing with fire, from the Greek pur and graphos. It can be practiced using specialized modern pyrography tools, or using a metal implement heated in a fire, Pyrography dates from the 17th century and reached its highest standard in the 19th century. In its crude form it is pokerwork, a large range of tones and shades can be achieved. Varying the type of tip used, the temperature, or the way the iron is applied to the material all create different effects, after the design is burned in, wooden objects are often coloured. Light-coloured hardwoods such as sycamore, basswood, beech and birch are most commonly used, however, other woods, such as maple, pine or oak, are also used. Pyrography is also applied to items, using the same hot-iron technique. Leather lends itself to bold designs, and also very subtle shading to be achieved. Specialist vegetable-tanned leather must be used for pyrography, typically in light colours for good contrast, Pyrography is also popular among gourd crafters and artists, where designs are burned onto the exterior of a dried hard-shell gourd. The process has been practiced by a number of cultures including the Egyptians, Pyrographer Robert Boyer hypothesises that the art form dates back to prehistory, when early humans created designs using the charred remains of their fires. It was known in China from the time of the Han dynasty and this improved the pokerwork process by allowing the addition of tinting and shading that were previously impossible. Pyrography is a folk art in many parts of Europe, including Romania, Hungary and Flanders, as well as Argentina. Traditional pyrography can be performed using any heated metal implement, modern pyrography machines exist, and can be divided into three main categories. Solid-point burners are similar in design to a soldering iron and they have a solid brass tip which is heated by an electrical element, and operate at a fixed temperature. Wire-nib burners have variable temperature controls, the writing nib is heated by an electric current passing directly through it. Some models have interchangeable nibs to allow for different effects, laser cutters can be set to scorch the material instead of cutting all the way through it. Many laser cutters provide software facilities to import image files and transfer them onto a sheet of wood, some laser systems are sufficiently sensitive to perform pyrography on thin card or even paper. Woods differ in hardness, grain, figure, texture, color, hardness, All woods can be classified into hard or soft
4.
Blow torch
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A blowtorch, or blowlamp, is a fuel-burning tool used for applying flame and heat to various applications, usually metalworking. Early blowtorches used liquid fuel, carried in a reservoir attached to the lamp. Their fuel reservoir is disposable or refillable by exchange, the term blowlamp usually refers to liquid-fuelled torches still used in the UK. Liquid-fuelled torches are pressurized by a hand pump, while gas torches are self-pressurized by the fuel evaporation. Fuel torches are available in a vast range of size and output power, the term blowtorch applies to the smaller and lower temperature range of these. Blowtorches are typically a single unit, with their draught supplied by a natural draught of air. The larger torches may have a fuel reservoir placed on the ground. This is common for butane- or propane-fuelled gas torches, but also applies to the older, many torches now use a hose-supplied gas feed, which is often mains gas. They may also have a supply, from either an air blower or an oxygen cylinder. Both of these larger and more powerful designs are commonly described as blowtorches, while the term blowtorch is usually reserved for the smaller. The archaic term blowpipe is sometimes used in relation to oxy-acetylene welding torches. The blowtorch is of ancient origin and was used as a tool by gold and they began literally as a blown lamp, a wick oil lamp with a mouth-blown tube alongside the flame. This type of lamp, with fuel, continued to be in use for such small tasks into the late 20th century. In 1797 or in 1799 German inventor August von Marquardt invented a blowtorch in Eberswalde, another early blow pipe patent comes from USA, dated May 13,1856. In 1882, a new vaporizing technique was developed by Carl Richard Nyberg in Sweden, and the year after and it was quickly copied or licensed by many other manufacturers. The US blowtorch was independently developed with a flared base and was fuelled by gasoline, whereas the European versions used kerosene for safety. There remain several manufacturers producing brass blowtorches in India, China, the blowtorch is commonly used where a diffuse high temperature naked flame heat is required but not so hot as to cause combustion or welding. Temperature applications, soldering, brazing, softening paint for removal, melting roof tar and it is also used in cooking, one common use is for the creation of the layer of hard caramelized sugar in a crème brûlée
5.
Thermostat
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A thermostat is a component which senses the temperature of a system so that the systems temperature is maintained near a desired setpoint. It is a closed loop control device, as it seeks to reduce the error between the desired and measured temperatures, sometimes a thermostat combines both the sensing and control action elements of a controlled system, such as in an automotive thermostat. A thermostat exerts control by switching heating or cooling devices on or off, or by regulating the flow of a heat transfer fluid as needed, to maintain the correct temperature. Thermostats can be constructed in ways and may use a variety of sensors to measure the temperature. The output of the sensor then controls the heating or cooling apparatus, instead, the heating or cooling equipment runs at full capacity until the set temperature is reached, then shuts off. Increasing the difference between the setting and the desired temperature therefore does not shorten the time to achieve the desired temperature. A thermostat may have a maximum switching frequency, or switch heating and cooling equipment on and this reduces the risk of equipment damage from frequent switching. The term thermostat is derived from the Greek words θερμός thermos, hot and στατός statos, standing, early technologies included mercury thermometers with electrodes inserted directly through the glass, so that when a certain temperature was reached the contacts would be closed by the mercury. These were accurate to within a degree of temperature, common sensor technologies in use today include, Bimetallic mechanical or electrical sensors. He invented a mercury thermostat to regulate the temperature of a chicken incubator and this is one of the first recorded feedback-controlled devices. Modern thermostat control was developed in the 1830s by Andrew Ure, a Scottish chemist, Warren S. Johnson of Wisconsin patented a bi-metal room thermostat in 1883, and two years later filed a patent for the first multi-zone thermostatic control system. Albert Butz invented the electric thermostat and patented it in 1886, one of the first industrial uses of the thermostat was in the regulation of the temperature in poultry incubators. Charles Hearson, a British engineer, designed the first modern incubator for eggs that was taken up for use on farms in 1879. The incubators incorporated an accurate thermostat to regulate the temperature so as to simulate the experience of an egg being hatched naturally. This covers only devices which both sense and control using purely mechanical means, domestic water and steam based central heating systems have traditionally been controlled by bi-metallic strip thermostats, and this is dealt with later in this article. Purely mechanical control has been localised steam or hot-water radiator bi-metallic thermostats which regulated the individual flow, however, Thermostatic Radiator Valves are now being widely used. Purely mechanical thermostats are used to regulate dampers in some rooftop turbine vents, some automobile passenger heating systems have a thermostatically controlled valve to regulate the water flow and temperature to an adjustable level. In older vehicles the thermostat controls the application of engine vacuum to actuators that control water valves, in modern vehicles, the vacuum actuators may be operated by small solenoids under the control of a central computer
6.
Thermocouple
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A thermocouple is an electrical device consisting of two dissimilar conductors forming electrical junctions at differing temperatures. A thermocouple produces a temperature-dependent voltage as a result of the effect. Thermocouples are a widely used type of temperature sensor, commercial thermocouples are inexpensive, interchangeable, are supplied with standard connectors, and can measure a wide range of temperatures. In contrast to most other methods of measurement, thermocouples are self powered. The main limitation with thermocouples is accuracy, system errors of less than one degree Celsius can be difficult to achieve, Thermocouples are widely used in science and industry, applications include temperature measurement for kilns, gas turbine exhaust, diesel engines, and other industrial processes. Thermocouples are also used in homes, offices and businesses as the sensors in thermostats. At the time Seebeck referred to this as thermo-magnetism, the magnetic field he observed was later shown to be due to thermo-electric current. In practical use, the voltage generated at a junction of two different types of wire is what is of interest as this can be used to measure temperature at very high. The magnitude of the voltage depends on the types of wire used, generally, the voltage is in the microvolt range and care must be taken to obtain a usable measurement. Although current flows very little, power can be generated by a thermocouple junction. Power generation using multiple thermocouples, as in a thermopile, is common, the standard configuration for thermocouple usage is shown in the figure. Briefly, the desired temperature Tsense is obtained using three inputs—the characteristic function E of the thermocouple, the measured voltage V, and the reference junctions temperature Tref, the solution to the equation E = V + E yields Tsense. These details are hidden from the user since the reference junction block, voltmeter. The Seebeck effect refers to an electromotive force whenever there is a gradient in a conductive material. The standard measurement configuration shown in the figure, shows four temperature regions and thus four voltage contributions, Change from T m e t e r to T r e f, Change from T r e f to T s e n s e, in the alumel wire. Change from T s e n s e to T r e f, Change from T r e f to T m e t e r, in the upper copper wire. The first and fourth contributions cancel out exactly, because these regions involve the same temperature change, as a result, T m e t e r does not influence the measured voltage. The second and third contributions do not cancel, as they involve different materials, an integral does not need to be performed for every temperature measurement
7.
Rework (electronics)
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Rework is the term for the refinishing operation or repair of an electronic printed circuit board assembly, usually involving desoldering and re-soldering of surface-mounted electronic components. A hot air gun or hot air station is used to heat devices and melt solder, a rework station is a place to do this work—the tools and supplies for this work, typically on a workbench. Reasons for rework of electronics include, Poor solder joints due to faulty assembly or thermal cycling, solder bridges—unwanted drops of solder that connect points that should be isolated from each other. The rework may involve several components, which must be worked on one by one without damage to surrounding parts or the PCB itself, all parts not being worked on are protected from heat and damage. Thermal stress on the assembly is kept as low as possible to prevent unnecessary contractions of the board which might cause immediate or future damage. In the 21st century, almost all soldering is carried out with lead-free solder, where this precaution is not necessary, tin-lead solder melts at a lower temperature and is easier to work with. Heating a single SMD with a gun to melt all solder joints between it and the PCB is usually the first step, followed by removing the SMD while the solder is molten. The pad array on the board should then be cleaned of old solder. It is quite easy to remove these residues by heating them to melting temperature, a soldering iron or hot air gun can be used with desoldering braid. The precise placement of the new unit onto the prepared pad array requires skilful use of a highly accurate vision-alignment system with resolution and magnification. The smaller the pitch and size of the components, the more precise working must be, finally the newly placed SMD is soldered onto the board. High quality demands or specific designs of SMDs require the application of solder paste before positioning and soldering the unit. The surface tension of the solder, which is on the boards solder pads, tends to pull the device into precise alignment with the pads if not initially positioned totally correctly. Connecting pins are not accessible from the top for testing, bad connections produced during assembly can be detected and the assembly reworked. Assemblies which fail due to bad BGA connections can be repaired either by reflowing, or by removing the device and cleaning it of solder, reballing, devices can be recovered from scrapped assemblies for reuse in the same way. This may or not resolve the problem, and there is a chance that the board will fail again after some time. For typical devices one repair company estimates that the process, if there are no unexpected problems, reflowing can done non-professionally in a domestic oven or with a heat gun. For the PS3 and Xbox mentioned above, the time is about 120 minutes if all goes well, chips are at risk of being damaged by the repeated heating and cooling of reballing, and manufacturers warranties sometimes do not cover this case
8.
Through-hole technology
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Through-hole technology almost completely replaced earlier electronics assembly techniques such as point-to-point construction. From the second generation of computers in the 1950s until surface-mount technology became popular in the late 1980s, pCBs initially had tracks printed on one side only, later both sides, then multi-layer boards were in use. Through holes became plated-through holes in order for the components to make contact with the conductive layers. Components with wire leads are used on through-hole boards. Axial leads protrude from each end of a cylindrical or elongated box-shaped component. Axial-leaded components resemble wire jumpers in shape, and can be used to short distances on a board. Axial components do not protrude much above the surface of a board, radial leads project more or less in parallel from the same surface or aspect of a component package, rather than from opposite ends of the package. Originally, radial leads were defined as following a radius of a cylindrical component. Over time, this definition was generalized in contrast to axial leads, when placed on a board, radial components stand up perpendicular, occupying a smaller footprint on sometimes-scarce board real estate, making them useful in many high-density designs. The parallel leads projecting from a mounting surface gives radial components an overall plugin-nature. When needed, a component can be effectively converted into a radial component, by bending one of its leads into a U shape so that it ends up close to. Extra insulation with heat-shrink tubing may be used to prevent shorting out on nearby components, conversely, a radial component can be pressed into service as an axial component by separating its leads as far as possible, and extending them into an overall length-spanning shape. These improvisations are often seen in breadboard or prototype construction, but are deprecated for mass production designs and this is because of difficulties in use with automated component placement machinery, and poorer reliability because of reduced vibration and mechanical shock resistance in the completed assembly. While through-hole mounting provides strong mechanical bonds when compared to SMT techniques and they also limit the available routing area for signal traces on layers immediately below the top layer on multilayer boards since the holes must pass through all layers to the opposite side. Design engineers often prefer the larger through-hole rather than surface mount parts when prototyping, however, high-speed or high-frequency designs may require SMT technology to minimize stray inductance and capacitance in wire leads, which would impair circuit function. Ultra-compact designs may also dictate SMT construction, even in the phase of design. Board to board connectors Surface-mount technology Via Through hole Lesser, Roger, Alderton, flexible production cell for led arrays. Fabrication, Visiting a production line of Kingston memory modules, hole sizes for through-hole parts at Wikibooks
9.
Redox
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Redox is a chemical reaction in which the oxidation states of atoms are changed. Any such reaction involves both a process and a complementary oxidation process, two key concepts involved with electron transfer processes. Redox reactions include all chemical reactions in which atoms have their oxidation state changed, in general, the chemical species from which the electron is stripped is said to have been oxidized, while the chemical species to which the electron is added is said to have been reduced. It can be explained in terms, Oxidation is the loss of electrons or an increase in oxidation state by a molecule, atom. Reduction is the gain of electrons or a decrease in state by a molecule, atom. As an example, during the combustion of wood, oxygen from the air is reduced, the reaction can occur relatively slowly, as in the case of rust, or more quickly, as in the case of fire. Redox is a portmanteau of reduction and oxidation, the word oxidation originally implied reaction with oxygen to form an oxide, since dioxygen was historically the first recognized oxidizing agent. Later, the term was expanded to encompass oxygen-like substances that accomplished parallel chemical reactions, ultimately, the meaning was generalized to include all processes involving loss of electrons. The word reduction originally referred to the loss in weight upon heating a metallic ore such as an oxide to extract the metal. In other words, ore was reduced to metal, antoine Lavoisier showed that this loss of weight was due to the loss of oxygen as a gas. Later, scientists realized that the atom gains electrons in this process. The meaning of reduction then became generalized to all processes involving gain of electrons. Even though reduction seems counter-intuitive when speaking of the gain of electrons, it help to think of reduction as the loss of oxygen. Since electrons are charged, it is also helpful to think of this as reduction in electrical charge. The electrochemist John Bockris has used the words electronation and deelectronation to describe reduction and oxidation processes respectively when they occur at electrodes and these words are analogous to protonation and deprotonation, but they have not been widely adopted by chemists. The term hydrogenation could be used instead of reduction, since hydrogen is the agent in a large number of reactions. But, unlike oxidation, which has been generalized beyond its root element, the word redox was first used in 1928. The processes of oxidation and reduction occur simultaneously and cannot happen independently of one another, the oxidation alone and the reduction alone are each called a half-reaction, because two half-reactions always occur together to form a whole reaction
10.
Welding
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In addition to melting the base metal, a filler material is typically added to the joint to form a pool of molten material that cools to form a joint that is usually stronger than the base material. Pressure may also be used in conjunction with heat, or by itself, although less common, there are also solid state welding processes such as friction welding or shielded active gas welding in which metal does not melt. Some of the best known welding methods include, Oxy-fuel welding - also known as oxyacetylene welding or oxy welding, uses fuel gases and oxygen to weld and cut metals. Shielded metal arc welding – also known as stick welding or electric welding, the electrode holder holds the electrode as it slowly melts away. Slag protects the weld puddle from atmospheric contamination, gas tungsten arc welding – also known as TIG, uses a non-consumable tungsten electrode to produce the weld. The weld area is protected from contamination by an inert shielding gas such as argon or helium. Flux-cored arc welding – almost identical to MIG welding except it uses a special tubular wire filled with flux, it can be used with or without shielding gas, submerged arc welding – uses an automatically fed consumable electrode and a blanket of granular fusible flux. The molten weld and the arc zone are protected from contamination by being submerged under the flux blanket. Electroslag welding – a highly productive, single pass welding process for thicker materials between 1 inch and 12 inches in a vertical or close to vertical position. Electric resistance welding - a welding process that produces coalescence of laying surfaces where heat to form the weld is generated by the resistance of the material. In general, an efficient method, but limited to relatively thin material, many different energy sources can be used for welding, including a gas flame, an electric arc, a laser, an electron beam, friction, and ultrasound. While often a process, welding may be performed in many different environments, including in open air, under water. Welding is an undertaking and precautions are required to avoid burns, electric shock, vision damage, inhalation of poisonous gases and fumes. Until the end of the 19th century, the welding process was forge welding. Arc welding and oxyfuel welding were among the first processes to develop late in the century, Welding technology advanced quickly during the early 20th century as the world wars drove the demand for reliable and inexpensive joining methods. Developments continued with the invention of laser welding, electron beam welding, magnetic pulse welding. Today, the continues to advance. Robot welding is commonplace in industrial settings, and researchers continue to develop new welding methods, the history of joining metals goes back several millennia
11.
Air hammer (fabrication)
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An air hammer, also known as an air chisel, is a pneumatic hand tool used to carve in stone, and to break or cut metal objects apart. It is designed to accept different tools depending on the required function, the following are various tools that can be used in the air hammer, Universal joint and tie-rod tool Used to separate universal joints and tie-rod ends. Ball joint separator Used to separate ball joints, shock absorber chisel Used to break loose shock absorber nuts. Exhaust pipe cutter Used to cut through exhaust pipe for disassembly, tapered punch A general tool that can be used to free frozen nuts, insert pins, and align holes. Rubber bushing splitter Used to remove rubber bushings, free-standing air hammers are an adaptation of the hand-held version. An air hammer can stretch or shrink a variety of metals, from thin aircraft aluminums and they are also used for smoothing metal that has already been roughed, shaped or formed. In the 1920s, two devices were invented that would permanently change the way metal and stone were hammered. The pneumatic rivet gun was developed to set hot rivets on girder bridges. This tool was later scaled down for metal, as the 1930s saw the advent of monocoque aluminum aircraft. The other new device, hitting at twice or three times the speed of the gun, was the stone carvers hammer – a great blessing for smooth and rapid dressing of granite. In 1930 F. J. Hauschild adapted the original stone carvers hammer into a portable hand-held steel tube frame for the purpose of straightening auto bodies. For the next 25 years his Rams Head Body and Fender Machine improved and increased production for auto body work men all over the U. S, post-war industry brought many new applications for the air hammer technology. Among these were, sand rammers and tampers for sand casting metal plating rack scalers weld chippers destruction guns for cleaning up concrete needle scalers pavement breakers metal chisels, each of these tools has a different purpose despite nearly identical appearance in many cases. Air Power Hammer shrinking 14-gauge steel demonstrated
12.
Bandsaw
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A bandsaw is a saw with a long sharp blade consisting of a continuous band of toothed metal stretched between two or more wheels to cut material. They are used principally in woodworking, metalworking, and lumbering, advantages include uniform cutting action as a result of an evenly distributed tooth load, and the ability to cut irregular or curved shapes like a jigsaw. The minimum radius of a curve is determined by the width of the band, most bandsaws have two wheels rotating in the same plane, one of which is powered, although some may have three or four to distribute the load. The blade itself can come in a variety of size and tooth pitch which enables the machine to be versatile and able to cut a wide variety of materials including wood, metal. Almost all bandsaws today are powered by an electric motor, line shaft versions were once common but are now antiques. Constant flexing of the blade over the wheels caused either the material or the joint welding it into a loop to fail, nearly 40 years passed before Frenchwoman Anne Paulin Crepin devised a welding technique overcoming this hurdle. She applied for a patent in 1846, and soon sold the right to employ it to manufacturer A. Perin & Company of Paris. Combining this method with new alloys and advanced tempering techniques allowed Perin to create the first modern band saw blade. The first American band saw patent was granted to Benjamin Barker of Ellsworth, Maine, the first factory produced and commercially available band saw in the U. S. was by a design of Paul Prybil. Power hacksaws were once common in the industries, but bandsaws. Many workshops in residential garages or basements and in light industry contain small or medium-sized bandsaws that can cut wood, metal, often a general-purpose blade is left in place, although blades optimized for wood or metal can be switched out when volume of use warrants. Most residential and commercial bandsaws are of the vertical type mounted on a bench or a cabinet stand, Portable power tool versions, including cordless models, are also common in recent decades, allowing building contractors to bring them along on the truck to the jobsite. Saws for cutting meat are typically of all steel construction with easy to clean features. The blades either have fine teeth with heat treated tips, or have plain or scalloped knife edges, bandsaws dedicated to industrial metal-cutting use, such as for structural steel in fabrication shops and for bar stock in machine shops, are available in vertical and horizontal designs. Typical band speeds range from 40 feet per minute to 5,000 feet per minute, although specialized bandsaws are built for friction cutting of hard metals, metal-cutting bandsaws are usually equipped with brushes or brushwheels to prevent chips from becoming stuck in between the blades teeth. Systems which cool the blade with cutting fluid are also common equipment on metal-cutting bandsaws, the coolant washes away swarf and keeps the blade cool and lubricated. Horizontal bandsaws hold the workpiece stationary while the blade swings down through the cut and this configuration is used to cut long materials such as pipe or bar stock to length. Thus it is an important part of the facilities in most machine shops, the horizontal design is not useful for cutting curves or complicated shapes
Choosing a soldering tip at Wikibooks
