|
Drills
A drill is a tool used for making round holes or driving fasteners. It is fitted with a bit, either a drill or driverchuck. Hand-operated types are dramatically decreasing in popularity and cordless battery-powered ones proliferating due to increased efficiency and ease of use. Drills are commonly used in woodworking, metalworking, construction, machine tool fabrication, construction and utility projects. Specially designed versions are made for miniature applications. History Around 35,000 BC, ''Homo sapiens'' discovered the benefits of the application of rotary tools. This would have rudimentarily consisted of a pointed rock being spun between the hands to bore a hole through another material. This led to the hand drill, a smooth stick, that was sometimes attached to flint point, and was rubbed between the palms. This was used by many ancient civilizations around the world including the Mayans. The earliest perforated artifacts, such as bone, ivory, shells, and antlers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drill Scheme
A drill is a tool used for making round holes or driving fasteners. It is fitted with a bit, either a drill or driverchuck. Hand-operated types are dramatically decreasing in popularity and cordless battery-powered ones proliferating due to increased efficiency and ease of use. Drills are commonly used in woodworking, metalworking, construction, machine tool fabrication, construction and utility projects. Specially designed versions are made for miniature applications. History Around 35,000 BC, ''Homo sapiens'' discovered the benefits of the application of rotary tools. This would have rudimentarily consisted of a pointed rock being spun between the hands to bore a hole through another material. This led to the hand drill, a smooth stick, that was sometimes attached to flint point, and was rubbed between the palms. This was used by many ancient civilizations around the world including the Mayans. The earliest perforated artifacts, such as bone, ivory, shells, and antler ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drill Bit
Drill bits are cutting tools used in a drill to remove material to create holes, almost always of circular cross-section. Drill bits come in many sizes and shapes and can create different kinds of holes in many different materials. In order to create holes drill bits are usually attached to a drill, which powers them to cut through the workpiece, typically by rotation. The drill will grasp the upper end of a bit called the ''shank'' in the chuck. Drills come in standardized drill bit sizes. A comprehensive drill bit and tap size chart lists metric and imperial sized drills alongside the required screw tap sizes. There are also certain specialized drill bits that can create holes with a non-circular cross-section. Characteristics Drill geometry has several characteristics: *The spiral (or rate of twist) in the drill bit controls the rate of chip removal. A fast spiral (high twist rate or "compact flute") drill bit is used in high feed rate applications under low spindle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Core Drill
A modern core drill is a drill specifically designed to remove a cylinder of material, much like a hole saw. The material left inside the drill bit is referred to as the ''core''. Core drills used in metal are called annular cutters. Core drills used for concrete and hard rock generally use industrial diamond grit as the abrasive material and may be electrical, pneumatic or hydraulic powered. Core drills are commonly water cooled, and the water also carries away the fine waste as a slurry. For drilling masonry, carbide core drills can be used, but diamond is more successful when cutting through rebar. The earliest core drills were those used by the ancient Egyptians, invented in 3000 BC. Core drills are used for many applications, either where the core needs to be preserved (the drilling apparatus used in obtaining a core sample is often referred to as a corer), or where drilling can be done more rapidly since much less material needs to be removed than with a standard bit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Drill
A magnetic drilling machine is a portable drilling machine with a magnetic base (either electromagnetic or permanent magnet). It can use twist drill bits, annular cutters, milling cutters, and other rotary cutters. With suitable bits it can also tap threads, ream, and countersink. Its combination of a stable magnetic base and low RPM help resist or reduce torque forces created by large diameter bits. Magnetic drilling machines with reversible motor and variable speed controls can also perform operations like tapping, countersink and reaming. Magnetic drilling machine with cross table base and can also perform light milling. Description A portable magnetic drilling machine is faster and more portable alternative to hole making machines such as the drill press, and is more accurate than a hand drill. A portable magnetic drilling machine is used on steel or other magnetic materials. It gives an accuracy of 0.01 mm to 0.05mm in steel or other magnetic material. The drill bits use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chuck (engineering)
A chuck is a specialized type of clamp used to hold an object with radial symmetry, especially a cylinder. In a drill, a mill and a transmission, a chuck holds the rotating tool; in a lathe, it holds the rotating workpiece. Chucks commonly use jaws to hold the tool or workpiece. The jaws (sometimes called dogs) are typically arranged in a radially symmetrical pattern like the points of a star. Jawed chucks may require a wrench-like device called a ''chuck key'' to be tightened or loosened, but other jawed chucks may be tightened or loosened by hand force alone, offering convenience at the expense of gripping force. Chucks on some lathes have jaws that move independently, allowing them to hold irregularly shaped objects. More complex designs might include specially shaped jaws, greater numbers of jaws, or quick-release mechanisms. Instead of jaws, a chuck may use magnetism, vacuum, or collets, which are flexible collars or sleeves that fit closely around the tool or work ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bow Drill
A bow drill is a simple hand-operated type of tool, consisting of a rod (the ''spindle'' or ''drill shaft'') that is set in rapid rotary motion by means of a cord wrapped around it, kept taut by a bow which is pushed back and forth with one hand. This tool of prehistoric origin has been used both as a drill, to make holes on solid materials such as wood, stone, bone, or teeth, and as a fire drill to start a fire. The spindle can be held in a fixed frame, or by a hand-held block (the ''hand piece'' or ''thimble'') with a hole into which the top of the shaft is inserted. Some lubricant should be used to reduce friction between these two parts. A popular campcraft book of 1920 attributed this invention to the Inuit. In Mehrgarh (Pakistan) it has been dated between the 4th-5th millennium BCE. The string of the bow is wrapped once around the spindle, so that it is tight enough not to slip during operation. In the variation called the Egyptian bow drill, the cord is wound aro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Screwdriver
A screwdriver is a tool, manual or powered, used for turning screws. A typical simple screwdriver has a handle and a shaft, ending in a tip the user puts into the screw head before turning the handle. This form of the screwdriver has been replaced in many workplaces and homes with a more modern and versatile tool, a power drill, as they are quicker, easier, and can also drill holes. The shaft is usually made of tough steel to resist bending or twisting. The tip may be hardened to resist wear, treated with a dark tip coating for improved visual contrast between tip and screw—or ridged or treated for additional 'grip'. Handles are typically wood, metal, or plastic and usually hexagonal, square, or oval in cross-section to improve grip and prevent the tool from rolling when set down. Some manual screwdrivers have interchangeable tips that fit into a socket on the end of the shaft and are held in mechanically or magnetically. These often have a hollow handle that contains various t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mehrgarh
Mehrgarh (; ur, ) is a Neolithic archaeological site (dated ) situated on the Kacchi Plain of Balochistan in Pakistan. It is located near the Bolan Pass, to the west of the Indus River and between the modern-day Pakistani cities of Quetta, Kalat and Sibi. The site was discovered in 1974 by an archaeological team led by the French archaeologists Jean-François Jarrige and his wife, Catherine Jarrige. Mehrgarh was excavated continuously between 1974 and 1986, and again from 1997 to 2000. Archaeological material has been found in six mounds, and about 32,000 artifacts have been collected from the site. The earliest settlement at Mehrgarh—located in the northeast corner of the site—was a small farming village dated between 7000 BCE and 5500 BCE. History Mehrgarh is one of the earliest known sites that shows evidence of farming and herding in South Asia.UNESCO World Heritage. 2004. ''Archaeological Site of Mehrgarh''Hirst, K. Kris. 2005"Mehrgarh". '' Guide to Archaeology'' ... [...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, 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 work piece 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 " 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, as discussed below. While all machine tools are "machines that help people to make things", not all factory machines are machine tools. Today machine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thebes, Egypt
, image = Decorated pillars of the temple at Karnac, Thebes, Egypt. Co Wellcome V0049316.jpg , alt = , caption = Pillars of the Great Hypostyle Hall, in ''The Holy Land, Syria, Idumea, Arabia, Egypt, and Nubia'' , map_type = Egypt , map_alt = , map_size = , relief = yes , coordinates = , location = Luxor, Luxor Governorate, Egypt , region = Upper Egypt , type = Settlement , part_of = , length = , width = , area = , height = , builder = , material = , built = , abandoned = , epochs = , cultures = , dependency_of = , occupants = , event = , excavations = , archaeologists = , condition = , ownership = , management = , public_access = , website = , notes = , designation1 = WHS , designation1_offname = Ancient Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hieroglyphs
A hieroglyph (Greek for "sacred carvings") was a character of the ancient Egyptian writing system. Logographic scripts that are pictographic in form in a way reminiscent of ancient Egyptian are also sometimes called "hieroglyphs". In Neoplatonism, especially during the Renaissance, a "hieroglyph" was an artistic representation of an esoteric idea, which Neoplatonists believed actual Egyptian hieroglyphs to be. The word ''hieroglyphics'' refers to a hieroglyphic script. The Egyptians invented the pictorial script, which refers to any writing system that employs images as symbols for various semantic entities, rather than the abstract signs used by alphabets. The appearance of these distinctive figures in 3000 BCE marked the beginning of Egyptian civilization. Though based on images, Egyptian script was more than a sophisticated form of picture-writing. Each picture/ glyph served one of three functions: (1) to represent the image of a thing or action, (2) to stand for a sound or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flint
Flint, occasionally flintstone, is a sedimentary cryptocrystalline form of the mineral quartz, categorized as the variety of chert that occurs in chalk or marly limestone. Flint was widely used historically to make stone tools and start fires. It occurs chiefly as nodules and masses in sedimentary rocks, such as chalks and limestones.''The Flints from Portsdown Hill'' Inside the nodule, flint is usually dark grey, black, green, white or brown in colour, and often has a glassy or waxy appearance. A thin layer on the outside of the nodules is usually different in colour, typically white and rough in texture. The nodules can often be found along s and |
.jpg "Click for more on -> Chuck (engineering)")
.jpg "Click for more on -> Screwdriver")
