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Hand Scraper
A hand scraper is a single-edged tool used to scrape metal or other materials from a surface. This may be required where a surface needs to be trued, corrected for fit to a mating part, retain oil (usually on a freshly ground surface), or be given a decorative finish. Surface plates were traditionally made by scraping. Three raw cast surface plates (plates that have been "seasoned" by having their residual stress relieved and receiving suitable surface treatments, but which remain unfinished), a flat scraper (as pictured at the top of the image), and a quantity of engineer's blue (or red lead) were all that was required in the way of tools. The scraper in the center of the image is a three corner scraper and is typically used to deburr holes or the internal surface of bush-type bearings. Bushes are typically made from bronze or a white metal. The scraper pictured at the bottom is a curved scraper. It has a slight curve in its profile and is also suitable for bush bear ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bronze
Bronze is an alloy consisting primarily of copper, commonly with about 12–12.5% tin and often with the addition of other metals (including aluminium, manganese, nickel, or zinc) and sometimes non-metals (such as phosphorus) or metalloids (such as arsenic or silicon). These additions produce a range of alloys some of which are harder than copper alone or have other useful properties, such as strength, ductility, or machinability. The archaeological period during which bronze was the hardest metal in widespread use is known as the Bronze Age. The beginning of the Bronze Age in western Eurasia is conventionally dated to the mid-4th millennium BCE (~3500 BCE), and to the early 2nd millennium BCE in China; elsewhere it gradually spread across regions. The Bronze Age was followed by the Iron Age, which started about 1300 BCE and reaching most of Eurasia by about 500 BCE, although bronze continued to be much more widely used than it is in modern times. Because historica ... [...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] |
Machine Tool
A machine tool is a machine for handling or machining metal or other rigid materials, usually by cutting, Boring (manufacturing), boring, grinding (abrasive cutting), grinding, shearing, or other forms of deformations. Machine tools employ some sort of tool that does the cutting or shaping. All machine tools have some means of constraining the workpiece and provide a guided movement of the parts of the machine. Thus, the relative movement between the workpiece and the cutting tool (which is called the toolpath) is controlled or constrained by the machine to at least some extent, rather than being entirely "offhand" or "wikt:freehand#Adjective, freehand". It is a power-driven metal cutting machine which assists in managing the needed relative motion between cutting tool and the job that changes the size and shape of the job material. The precise definition of the term ''machine tool'' varies among users. While all machine tools are "machines that help people to make things", not a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surface Tension
Surface tension is the tendency of liquid surfaces at rest to shrink into the minimum surface area possible. Surface tension (physics), tension is what allows objects with a higher density than water such as razor blades and insects (e.g. Gerridae, water striders) to float on a water surface without becoming even partly submerged. At liquid–air interfaces, surface tension results from the greater attraction of liquid molecules to each other (due to Cohesion (chemistry), cohesion) than to the molecules in the air (due to adhesion). There are two primary mechanisms in play. One is an inward force on the surface molecules causing the liquid to contract. Second is a tangential force parallel to the surface of the liquid. This ''tangential'' force is generally referred to as the surface tension. The net effect is the liquid behaves as if its surface were covered with a stretched elastic membrane. But this analogy must not be taken too far as the tension in an elastic membrane i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surface Grinder
Surface grinding is done on flat surfaces to produce a smooth finish. It is a widely used abrasive machining process in which a spinning wheel covered in rough particles (grinding wheel) cuts chips of metallic or nonmetallic substance from a workpiece, making a face of it flat or smooth. Sometimes a surface grinder is known as a ''flick grinder'' if great accuracy is not required, but a machine superior to a bench grinder is needed. Process Surface grinding is a finishing process that uses a rotating abrasive wheel to smooth the flat surface of metallic or nonmetallic materials to give them a more refined look by removing the oxide layer and impurities on work piece surfaces. This will also attain a desired surface for a functional purpose. The components of a surface grinding machine are an abrasive wheel, a workholding device known as a chuck, and a reciprocating or rotary table. The chuck holds the material in place by two processes: ferromagnetic pieces are held in place b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grinding Machine
A grinding machine, often shortened to grinder, is any of various power tools or machine tools used for grinding. It is a type of material removal using an abrasive wheel as the cutting tool. Each grain of abrasive on the wheel's surface cuts a small chip from the workpiece via shear deformation. Grinding as a type of machining is used to finish workpieces that must show high surface quality (e.g., low surface roughness) and high accuracy of shape and dimension. As the accuracy in dimensions in grinding is of the order of 0.000025 mm, in most applications, it tends to be a finishing operation and removes comparatively little metal, about 0.25 to 0.50 mm depth. However, there are some roughing applications in which grinding removes high volumes of metal quite rapidly. Thus, grinding is a diverse field. Overview The grinding machine consists of a bed with a fixture to guide and hold the workpiece and a power-driven grinding wheel spinning at the required speed. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lapping
Lapping is a machining process in which two surfaces are rubbed together with an abrasive between them, by hand movement or using a machine. Lapping often follows other subtractive processes with more aggressive material removal as a first step, such as milling and/or grinding. Lapping can take two forms. The first type of lapping (traditionally often called grinding), involves rubbing a brittle material such as glass against a surface such as iron or glass itself (also known as the "lap" or grinding tool) with an abrasive such as aluminum oxide, jeweller's rouge, optician's rouge, emery, silicon carbide, diamond, etc., between them. This produces microscopic conchoidal fractures as the abrasive rolls about between the two surfaces and removes material from both. The other form of lapping involves a softer material such as pitch or a ceramic for the lap, which is "charged" with the abrasive. The lap is then used to cut a harder material—the workpiece. The abrasive embe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prussian Blue
Prussian blue (also known as Berlin blue, Brandenburg blue, Parisian and Paris blue) is a dark blue pigment produced by oxidation of ferrous ferrocyanide salts. It has the chemical formula . It consists of cations, where iron is in the oxidation state of +3, and anions, where iron is in the oxidation state of +2, so, the other name of this salt is iron(III) hexacyanoferrate(II). Turnbull's blue is essentially identical chemically, excepting that it has different impurities and particle sizes—because it is made from different reagents—and thus it has a slightly different color. Prussian blue was created in the early 18th century and is the first modern chemical synthesis, synthetic pigment. It is prepared as a very fine colloidal dispersion, because the compound is not soluble in water. It contains variable amounts of other ions and its appearance depends sensitively on the size of the colloidal particles. The pigment is used in paints, it became prominent in 19th-century ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
White Metal
The white metals are a series of often decorative bright metal alloys used as a base for plated silverware, ornaments or novelties, as well as any of several lead-based or tin-based alloys used for things like bearings, jewellery, miniature figures, fusible plugs, some medals and metal type. The term is also used in the antiques trade for an item suspected of being silver, but not hallmarked. A white metal alloy may include antimony, tin, lead, cadmium, bismuth, and zinc (some of which are quite toxic). Not all of these metals are found in all white metal alloys. Metals are mixed to achieve a desired goal or need. As an example, a base metal for jewellery needs to be castable, polishable, have good flow characteristics, have the ability to cast fine detail without an excessive amount of porosity and cast at between . Silver In compliance with British law, the British fine art trade uses the term "white metal" in auction catalogues to describe foreign silver items which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bearing (mechanical)
A ball bearing A bearing is a machine element that constrains relative motion to only the desired motion and reduces friction between moving parts. The design of the bearing may, for example, provide for free linear movement of the moving part or for free rotation around a fixed axis; or, it may prevent a motion by controlling the vectors of normal forces that bear on the moving parts. Most bearings facilitate the desired motion by minimizing friction. Bearings are classified broadly according to the type of operation, the motions allowed, or the directions of the loads (forces) applied to the parts. The term "bearing" is derived from the verb " to bear"; a bearing being a machine element that allows one part to bear (i.e., to support) another. The simplest bearings are bearing surfaces, cut or formed into a part, with varying degrees of control over the form, size, roughness, and location of the surface. Other bearings are separate devices installed into a machine or mach ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
