ratio of word probabilities predicted from brain for pliers and screwdriver

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pliers

screwdriver

top 10 words in brain distribution (in article):
steel head cut handle form metal tool design hand edge
top 10 words in brain distribution (in article):
type design blade time size head allow steel common century
top 10 words in brain distribution (not in article):
iron blade cell hair type size shape produce century body
top 10 words in brain distribution (not in article):
light drink lamp wine beer water produce bottle animal valve
times more probable under pliers 30 20 10 6 4 2.5 1.25 1 1.25 2.5 4 6 10 20 30 times more probable under screwdriver
(words not in the model)
History. Pliers in the general sense are an ancient and simple invention, no singular point in history or singular inventor can be credited. Early metal working processes from several millennia BC would have required plier-like devices to handle hot materials in the process of smithing or casting. Development from wooden to bronze pliers would have probably happened sometime prior to 3000 BC. Among the oldest illustrations of pliers are those showing the Greek god Hephaestus in his smithy. Today, pliers intended principally to be used for safely handling hot objects are usually called tongs. The number of different designs of pliers grew with the invention of the different objects which they were used to handle: horse shoes, fasteners, wire, pipes, electrical and electronic components. Design. The basic design of pliers has changed little since their origins, with the pair of "handles", the "pivot" (often formed by a rivet), and the "head" section with the gripping jaws or cutting edges forming the three elements. In distinction to a pair of scissors or shears, the plier's jaws always meet each other at one pivot angle. Pliers are an instrument that convert a power grip—the curling of the fingers into the palm of the hand—into a precision grip, directing the power of the hand's grip in a precise fashion on to the objects to be gripped. The handles are long relative to the shorter nose of the pliers. The two arms thus act as first class levers with a mechanical advantage, increasing the force applied by the hand's grip and concentrating it on the work piece. The materials used to make pliers consist mainly of steel alloys with additives such as vanadium or chromium, to improve alloy strength and prevent corrosion. Often pliers have insulated grips to ensure better handling and prevent electrical conductivity. In some lines of fine work (such as jewellery or musical instrument repair), some specialised pliers feature a layer of comparatively soft metal (such as brass) over the two plates of the head of the pliers to reduce pressure placed on some fine tools or materials. Making entire pliers out of softer metals would be impractical, reducing the strength required to break or bend them. The screwdriver'" is a device specifically designed to insert and tighten, or to loosen and remove, screws. The screwdriver is made up of a head or tip, which engages with a screw, a mechanism to apply torque by rotating the tip, and some way to position and support the screwdriver. A typical hand screwdriver comprises an approximately cylindrical handle of a size and shape to be held by a human hand, and an axial shaft fixed to the handle, the tip of which is shaped to fit a particular type of screw. The handle and shaft allow the screwdriver to be positioned and supported and, when rotated, to apply torque. Screwdrivers are made in a variety of shapes, and the tip can be rotated manually or by an electric or other motor. A screw has a head with a contour such that an appropriate screwdriver tip can be engaged in it in such a way that the application of sufficient torque to the screwdriver will cause the screw to rotate. History. Gunsmiths still refer to a screwdriver as a "turnscrew", under which name it is an important part of a set of pistols. The name was common in earlier centuries, used by cabinet makers and shipwrights and perhaps other trades. The Cabinet-Maker's screwdriver is one of the longest-established handle forms, somewhat oval or elipsoid in cross section. This is variously attributed to improving grip or preventing the tool rolling off the bench, but there is no reason to suppose these are not rationalisations. The shape has been popular for a couple of hundred years. It is usually associated with a plain head for slotted screws, but has been used with many head forms. "See Also: "The History of Screws Types and variations. There are many types of screw heads, of which the most common are the slotted, Phillips, PoziDriv SupaDriv (crosspoint), Robertson, TORX, and Allen (hex). Screwdrivers come in a large variety of sizes to match those of screws, from tiny jeweler's screwdrivers up. If a screwdriver that is not the right size and type for the screw is used, it is likely that the screw will be damaged in the process of tightening it. This is less important for PoziDriv and SupaDriv, which are designed specifically to be more tolerant of size mismatch. When tightening a screw with force, it is important to press the head hard into the screw, again to avoid damaging the screw. Some manual screwdrivers have a ratchet action whereby the screwdriver blade is locked to the handle for clockwise rotation, but uncoupled for counterclockwise rotation when set for tightening screws; and vice versa for loosening. Many screwdriver designs have a handle with detachable head (the part of the screwdriver which engages with the screw), called "bits" as with drill bits, allowing a set of one handle and several heads to be used for a variety of screw sizes and types. This kind of design has allowed the development of electrically powered screwdrivers, which, as the name suggests, use an electric motor to rotate the bit. In such cases the terminology for power drills is used, e.g. "shank" or "collet". Some drills can also be fitted with screwdriver heads. Manual screw drivers with a spiral ratchet'" mechanism to turn pressure (linear motion) into rotational motion also exist, and predate electric screwdrivers. The user pushes the handle toward the workpiece, causing a pawl in a spiral groove to rotate the shank and the removable bit. The ratchet can be set to rotate left or right with each push, or can be locked so that the tool can be used like a conventional screwdriver. Once very popular, these spiral ratchet drivers, using proprietary bits, have been largely discontinued by manufacturers such as Stanley, although one can still find them at vintage tool auctions. Companies such as Lara Specialty Tools now offer a modernized version that uses standard 1 /4-inch hex shank power tool bits. Since a variety of drill bits are available in this format, it allows the tool to do double duty as a "push drill". Many modern electrical appliances, if they contain screws at all, use screws with heads other than the typical slotted or Phillips styles. TORX is one such pattern that has become very widespread. The main cause of this trend is manufacturing efficiency: TORX and other types are designed so the driver will not slip out of the fastener as will a Phillips driver. (Slotted screws are rarely used in mass-produced devices, since the driver is not inherently centered on the fastener). A benefit disadvantage of non-typical fasteners (depending on your point of view) is that it can be more difficult for users of a device to disassemble it than if more-common head types were used, but TORX and other drivers are widely available. Specialized patterns of security screws are also used, such as the Gamebit head style used in all Nintendo consoles, though drivers for most security heads are, again, readily available. While screwdrivers are designed for the above functions, they are commonly also used as improvised substitutes for pry bars, levers, and hole punches, as well as other tools. There is no such thing as a "left-handed screwdriver", as the device can easily be wielded in either hand. To be sent on an errand to find a left-handed screwdriver is often a test of stupidity, or is used as a metaphor for something useless. The term "Birmingham screwdriver" is used jokingly in the UK to denote a hammer or sledgehammer. The handle and shaft of screwdrivers have changed considerably over time. The design is influenced by both purpose and manufacturing requirements. The "Perfect Handle" screwdriver was first manufactured by HD Smith & Company that operated from 1850 to 1900. Many manufacturers adopted this handle design world wide. The "Flat Bladed" screwdriver was another design composed of drop forged steel with riveted wood handles? Among slotted screwdrivers, there are a couple of major variations at the blade or bit end involving the profile of the blade as viewed face-on. The more common type is sometimes referred to as keystone'", where the blade profile is slightly flared before tapering off at the end. To maximize access in space-restricted applications, the same edges for the "'cabinet'" variety, in contrast, are straight and parallel, meeting the end of the blade at a right angle.