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Drills
A drill is a tool used for making round holes or driving fasteners. It is fitted with a drill bit for making holes, or a screwdriver bit for securing fasteners. Historically, they were powered by hand, and later mains power, but cordless battery-powered drills are proliferating due to increased efficiency and ease of use. Drills are commonly used in woodworking, metalworking, construction, machine tool fabrication, and utility projects. Specially designed versions are made for surgery, dentistry, miniatures, and other 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 earlies ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drill Bit
A drill bit is a cutting tool 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 ... [...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. A magnetic drilling machine with a X-Y table, cross table base 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 d ... [...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 and arrow, 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 (tool), fire drill to Fire making#Friction, start a fire. The spindle can be held into 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, otherwise, it could lead to some trouble when doing it too fast. 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 i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mehrgarh
Mehrgarh is a Neolithic archaeological site situated on the Kacchi Plain of Balochistan, Pakistan, 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, Pakistan, Kalat and Sibi. The site was discovered in 1974 by the French Archaeological Mission led by the French people, French archaeologists Jean-François Jarrige and Catherine Jarrige (archaeologist), Catherine Jarrige. Mehrgarh was Archaeological excavation, 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 in South Asia showing evidence of farming and herding.UNESCO World Heritage. 2004. ' ... [...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] |
Pump Drill
A pump drill is a simple hand-powered device used to impart a rapid rotating motion to a rod (the ''spindle'' or ''drill shaft''). It can be used for fire making or as a drill to make holes in various materials. It consists of: the drill shaft, a narrow board with a hole through the center, a weight (usually a heavy disc) acting as a flywheel, and a length of rope, cord. The weight is attached to the shaft, near the bottom end, and the hole board is slipped over the top. The cord is run through a hole or slot near the top of the shaft and attached to both ends of the hole board. The length of the cord is such that, at its lowest position, the board lies just above the weight. The end of the shaft usually has a slot or hole that can hold a hard bit that does the actual drilling, either by abrasion or by cutting. For wood, the bit may be an auger (drill), auger bit or a simple triangular blade that can cut while rotating in either direction. To use, the shaft is first turned by h ... [...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] |
Ancient Egypt
Ancient Egypt () was a cradle of civilization concentrated along the lower reaches of the Nile River in Northeast Africa. It emerged from prehistoric Egypt around 3150BC (according to conventional Egyptian chronology), when Upper and Lower Egypt were amalgamated by Menes, who is believed by the majority of List of Egyptologists, Egyptologists to have been the same person as Narmer. The history of ancient Egypt unfolded as a series of stable kingdoms interspersed by the "Periodization of ancient Egypt, Intermediate Periods" of relative instability. These stable kingdoms existed in one of three periods: the Old Kingdom of Egypt, Old Kingdom of the Early Bronze Age; the Middle Kingdom of Egypt, Middle Kingdom of the Middle Bronze Age; or the New Kingdom of Egypt, New Kingdom of the Late Bronze Age. The pinnacle of ancient Egyptian power was achieved during the New Kingdom, which extended its rule to much of Nubia and a considerable portion of the Levant. After this period, Egypt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thebes, Egypt
Thebes (, , ''Thēbai''), known to the ancient Egyptians as Waset, was an ancient Egyptian city located along the Nile about south of the Mediterranean. Its ruins lie within the modern Egyptian city of Luxor. Thebes was the main city of the fourth Upper Egyptian nome (Sceptre nome) and was the capital of Egypt for long periods during the Middle Kingdom and New Kingdom eras. It was close to Nubia and the Eastern Desert, with its valuable mineral resources and trade routes. It was a religious center and the most venerated city during many periods of ancient Egyptian history. The site of Thebes includes areas on both the eastern bank of the Nile, where the temples of Karnak and Luxor stand and where the city was situated; and the western bank, where a necropolis of large private and royal cemeteries and funerary complexes can be found. In 1979, the ruins of ancient Thebes were classified by UNESCO as a World Heritage Site. Toponymy The Egyptian name for Thebes was ''w� ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hieroglyphs
Ancient Egyptian hieroglyphs ( ) were the formal writing system used in Ancient Egypt for writing the Egyptian language. Hieroglyphs combined ideographic, logographic, syllabic and alphabetic elements, with more than 1,000 distinct characters.In total, there were about 1,000 graphemes in use during the Old Kingdom period; this number decreased to 750–850 during the Middle Kingdom, but rose instead to around 5,000 signs during the Ptolemaic period. Antonio Loprieno, ''Ancient Egyptian: A Linguistic Introduction'' (Cambridge: Cambridge UP, 1995), p. 12. Cursive hieroglyphs were used for religious literature on papyrus and wood. The later hieratic and demotic Egyptian scripts were derived from hieroglyphic writing, as was the Proto-Sinaitic script that later evolved into the Phoenician alphabet. Egyptian hieroglyphs are the ultimate ancestor of the Phoenician alphabet, the first widely adopted phonetic writing system. Moreover, owing in large part to the Greek and Aramaic scripts ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
