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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] |
Iran
Iran, officially the Islamic Republic of Iran, and also called Persia, is a country located in Western Asia. It is bordered by Iraq and Turkey to the west, by Azerbaijan and Armenia to the northwest, by the Caspian Sea and Turkmenistan to the north, by Afghanistan and Pakistan to the east, and by the Gulf of Oman and the Persian Gulf to the south. It covers an area of , making it the 17th-largest country. Iran has a population of 86 million, making it the 17th-most populous country in the world, and the second-largest in the Middle East. Its largest cities, in descending order, are the capital Tehran, Mashhad, Isfahan, Karaj, Shiraz, and Tabriz. The country is home to one of the world's oldest civilizations, beginning with the formation of the Elamite kingdoms in the fourth millennium BC. It was first unified by the Medes, an ancient Iranian people, in the seventh century BC, and reached its territorial height in the sixth century BC, when Cyrus the Great fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mechanical Hand Tools
Mechanical may refer to: Machine * Machine (mechanical), a system of mechanisms that shape the actuator input to achieve a specific application of output forces and movement * Mechanical calculator, a device used to perform the basic operations of arithmetic * Mechanical energy, the sum of potential energy and kinetic energy * Mechanical system, a system that manages the power of forces and movements to accomplish a task * Mechanism (engineering), a portion of a mechanical device Other * Mechanical (character), one of several characters in Shakespeare's ''A Midsummer Night's Dream'' * A kind of typeface in the VOX-ATypI classification See also * Machine, especially in opposition to an electronic item * ''Mechanical Animals'', the third full-length studio release by Marilyn Manson * Manufactured or artificial, especially in opposition to a biological or natural component * Automation, using machine decisions and processing instead of human * Mechanization, using machine labor inste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brace (tool)
A brace is a hand tool used with a bit (drill bit or auger) to drill holes, usually in wood. Pressure is applied to the top and the tool is rotated with a U-shaped grip. Bits used come in a variety of types but the more commonly used Ridgeway- and Irwin- pattern bits also rely on a snail point (called the snail), which is a tapered screw point shaped the same as a wood screw thread, which helps to pull the bit into the wood as the user turns the brace handle and applies pressure The U-shaped part is a kind of crank. It gives the brace much greater torque than other kinds of hand-powered drills. A brace and bit can be used to drill much wider and deeper holes than can a geared hand-powered drill. The price of the greater torque is lower rotational speed; it is easy for a geared hand drill to achieve a rotational speed of several hundred revolutions per minute, but it requires considerable effort to achieve even 100 rpm with a brace. The front part of the brace consists of 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 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 bits or a simple triangular blade, that can cut while rotating in either directions. To use, the shaft is first turned by hand so that t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drill
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] |
Abrasive
An abrasive is a material, often a mineral, that is used to shape or finish a workpiece through rubbing which leads to part of the workpiece being worn away by friction. While finishing a material often means polishing it to gain a smooth, reflective surface, the process can also involve roughening as in satin, matte or beaded finishes. In short, the ceramics which are used to cut, grind and polish other softer materials are known as abrasives. Abrasives are extremely commonplace and are used very extensively in a wide variety of industrial, domestic, and technological applications. This gives rise to a large variation in the physical and chemical composition of abrasives as well as the shape of the abrasive. Some common uses for abrasives include grinding, polishing, buffing, honing, cutting, drilling, sharpening, lapping, and sanding (see abrasive machining). (For simplicity, "mineral" in this article will be used loosely to refer to both minerals and mineral-like substances ... [...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] |
Ember
An ember, also called a hot coal, is a hot lump of smouldering solid fuel, typically glowing, composed of greatly heated wood, coal, or other carbon-based material. Embers (hot coals) can exist within, remain after, or sometimes precede, a fire. Embers are, in some cases, as hot as the fire which created them. They radiate a substantial amount of heat long after the fire has been extinguished, and if not taken care of properly can rekindle a fire that is thought to be completely extinguished and can pose a fire hazard. In order to avoid the danger of accidentally spreading a fire, many campers pour water on the embers or cover them in dirt. Alternatively, embers can be used to relight a fire after it has gone out without the need to rebuild the fire – in a conventional fireplace, a fire can easily be relit up to 12 hours after it goes out, provided that there is enough space for air to circulate between the embers and the introduced fuel. They are often used for cooking ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charcoal
Charcoal is a lightweight black carbon residue produced by strongly heating wood (or other animal and plant materials) in minimal oxygen to remove all water and volatile constituents. In the traditional version of this pyrolysis process, called charcoal burning, often by forming a charcoal kiln, the heat is supplied by burning part of the starting material itself, with a limited supply of oxygen. The material can also be heated in a closed retort. Modern "charcoal" briquettes used for outdoor cooking may contain many other additives, e.g. coal. This process happens naturally when combustion is incomplete, and is sometimes used in radiocarbon dating. It also happens inadvertently while burning wood, as in a fireplace or wood stove. The visible flame in these is due to combustion of the volatile gases exuded as the wood turns into charcoal. The soot and smoke commonly given off by wood fires result from incomplete combustion of those volatiles. Charcoal burns at a higher temper ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fire Drill (tool)
A fire drill is a primitive device to start a fire by friction between a rapidly rotating wooden rod (the ''spindle'' or ''shaft'') and a cavity on a stationary wood piece (the ''hearth'' or ''fireboard''). The device can be any of the ancient types of hand-operated drills, including a hand drill, bow drill (or strap drill), or pump drill. The spindle is usually 1–2 cm thick and should end in a dull point. The spindle and fireboard should be made from dry, medium-soft non-resinous wood such as spruce, cedar, balsam, yucca, aspen, basswood, buckeye, willow, tamarack, or similar. Principle Whatever the method used to drive the shaft, its lower end is placed into a shallow cavity of the fireboard with "V" notch cut into it. The primary goal is to generate heat by the friction between the tip of the shaft and the fireboard. Rotation speed and pressure are both important to reach this goal. The heat eventually turns the wood at the point of contact into charcoal which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
