Screwdriver
Other names | Turnscrew |
---|---|
Classification | Hand tool |
Types | See List of screw drives |
Related | Hex key Wrench |
A screwdriver is a tool, manual or powered, used for turning screws.
Description
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
Handles are typically wood, metal, or plastic[1] 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 types and sizes of tips, and a reversible ratchet action that allows multiple full turns without repositioning the tip or the user's hand.
A screwdriver is classified by its tip, which is shaped to fit the driving surfaces (slots, grooves, recesses, etc.) on the corresponding screw head. Proper use requires that the screwdriver's tip engage the head of a screw of the same size and type designation as the screwdriver tip. Screwdriver tips are available in a wide variety of types and sizes (List of screw drives). The two most common are the simple 'blade'-type for slotted screws, and Phillips, generically called "cross-recess", "cross-head", or "cross-point".
A wide variety of power screwdrivers ranges from a simple "stick"-type with batteries, a motor, and a tip holder all inline, to powerful "pistol" type VSR (variable-speed reversible)
History
The earliest documented screwdrivers were used in the late Middle Ages. They were probably invented in the late 15th century, either in Germany or France. The tool's original names in German and French were Schraubenzieher[2][3][4][circular reference] (screw-tightener) and tournevis (turnscrew), respectively. The first documentation of the tool is in the medieval Housebook of Wolfegg Castle, a manuscript written sometime between 1475 and 1490.[5] These earliest screwdrivers had pear-shaped handles and were made for slotted screws (diversification of the many types of screwdrivers did not emerge until the Gilded Age). The screwdriver remained inconspicuous, however, as evidence of its existence throughout the next 300 years is based primarily on the presence of screws.
Screws were used in the 15th century to construct screw-cutting
The jaws that hold the
The screwdriver depended entirely on the screw, and it took several advances to make the screw easy enough to produce to become popular and widespread. The most popular door hinge at the time was the butt-hinge, but it was considered a luxury. The butt-hinge was handmade, and its constant motion required the security of a screw.
Screws were very hard to produce before the
Meanwhile, in
Handle
The handle and shaft of screwdrivers have changed considerably over time. The design is influenced by both purpose and manufacturing requirements. The "Perfect Pattern Handle"[
The shape and material of many modern screwdriver handles are designed
Some screwdrivers have a short hexagonal section at the top of the blade, adjacent to the handle, so that a ring spanner or open wrench can be used to increase the applied torque. Another option are "cabinet" screwdrivers which are made of flat bar stock and while the shaft may be rounded, will have a large flat section adjacent to the handle which a wrench (often an adjustable) may be used on for additional leverage. The offset screwdriver has a handle set at right angles to the small blade, providing access to narrow spaces and giving extra torque.
Drive tip
Screwdrivers come in a large range of sizes to accommodate various screws—from tiny jeweller's screwdrivers up. A screwdriver that is not the right size and type for the screw may damage the screw in the process of tightening it.
Some screwdriver tips are magnetic, so that the screw (unless non-magnetic) remains attached to the screwdriver. This is particularly useful for small screws, which are otherwise very difficult to attempt to handle. Many screwdriver designs have a handle with a detachable tip (the part of the screwdriver that engages the screw), called bits as with drill bits. This provides a set of one handle and several bits that can drive a variety of screw sizes and types.
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A jeweler's screwdriver
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Screwdriver with magnetic tip
Slotted
The tool used to drive a slotted screw head is called a standard, common blade, flat-blade, slot-head, straight, flat, flat-tip,[6] or "flat-head"[7] screwdriver. This last usage can be confusing, because the term flat-head also describes a screw with a flat top, designed to install in a countersunk hole. Furthermore, the term implies that a screwdriver has a "head"; it does not. Such a flat-headed screw may have a slotted, cross, square recessed, or combination head. Before the development of the newer bit types, the flat-blade was called the "Common-Blade", because it was the most common one. Depending on the application, the name of this screwdriver may differ. Within the automotive/heavy electric industries, it is known as a "flat head screwdriver";[8] within the avionics and mining industries, it is known as a "standard screwdriver".[9] Though there are many names; the original device from 1908 was known as a "flat-head screw turner".[citation needed]
Among slotted screwdrivers, variations at the blade or bit end involve the profile of the blade as viewed face-on (from the side of the tool). The more common type is sometimes called keystone, where the blade profile is slightly flared before tapering off at the end, which provides extra stiffness to the workface and makes it capable of withstanding more torque by gripping deeper in the screw slot. To maximize access in space-restricted applications, the cabinet variant screwdriver blade sides are straight and parallel, reaching the end of the blade at a right angle. This design is also frequently used in jeweler's screwdrivers.
Many textbooks and vocational schools[who?] instruct mechanics to grind down the tip of the blade, which, due to the taper, increases its thickness and consequently allows more precise engagement with the slot in the screw. This approach creates a set of graduated slotted screwdrivers that will fit a particular screw for a tighter engagement and reduce screw head deformation. However, many better-quality screwdriver blades are already induction-hardened (surface heat-treated), coated with black-oxide, black-phosphate, or diamond-coated to increase friction between the screwdriver tip and the screw.[10] Thus tip grinding after manufacture will likely compromise their durability so it is best to select the proper tip and avoid weakening the manufacture's treatments.
Phillips
Phillips screwdrivers come in several standard sizes, ranging from tiny "jeweler's" to those used for automobile frame assembly—or #000 to #4 respectively. This size number is usually stamped onto the shank (shaft) or handle for identification. Each bit size fits a range of screw sizes, more or less well. Each Phillips screwdriver size also has a related shank diameter. The driver has a 57° point and tapered, unsharp (rounded) flutes. The #1 and smaller bits come to a blunt point, but the #2 and above have no point, but rather a nearly squared-off tip, making each size incompatible with the other.
The design is often criticized for its tendency to cam out at lower torque levels than other "cross head" designs, an effect caused by the tapered profile of the flutes which makes them easier to insert into the screw than other similar styles. There has long been a popular belief that this was actually a deliberate feature of the design. Evidence is lacking for this specific narrative and the feature is not mentioned in the original patents.[11] However, a subsequent refinement to the original design described in US Patent #2,474,994[12][13][14] describes this feature.
Robertson
Robertson, also known as a square,
Reed and Prince
Reed and Prince, also called Frearson, is another historic cross-head screw configuration. The cross in the screw head is sharper and less rounded than a Phillips, and the bit has 45° flukes and a sharper, pointed end. Also, the Phillips screw slot is not as deep as the Reed and Prince slot.[19][20] In theory, different size R&P screws fit any R&P bit size.[21]
Pozidriv
Pozidriv and the related Supadriv are widely used in Europe and most of the Far East.[22] While Pozidriv screws have cross heads like Phillips and are sometimes thought effectively the same, the Pozidriv design allows higher torque application than Phillips. It is often claimed that they can apply more torque than any of the other commonly used cross-head screwdriver systems, due to a complex fluting (mating) configuration.
Japanese Industrial Standard (JIS)
Japanese Industrial Standard (JIS) cross-head screwdrivers are still another standard, often inaccurately called Japanese Phillips. Compatible screw heads are usually identifiable by a single depressed dot or an "X" to one side of the cross slot. This is a screw standard throughout the Asia market and Japanese imports. The driver has a 57° point with a flat tip.[23]
Other types
Many modern
Non-typical fasteners are commonplace in consumer devices for their ability to make disassembly more difficult, which is seen as a benefit for manufacturers but is considered a disadvantage by users than if more common head types were used. In microwave ovens, such screws deny casual access to the high-power kilovolt electrical components, which are very dangerous.
However, Torx and other drivers have become widely available to the consumer due to their increasing use in the industry. Some other styles fit a three-pointed star recess, and a five-lobed spline with rounded edges instead of the square edges of the Torx. This is called a Pentalobe.
Specialized patterns of security screws are also used, such as the Line Head (LH) style by OSG System Products, Japan, as used in many Nintendo consoles, though drivers for the more common security heads are, again, readily available. Another type of security head has smooth curved surfaces instead of the slot edges that would permit loosening the screw; it is found in public rest room privacy partitions, and cannot be removed by conventional screwdrivers.
Variations
Torque screwdrivers
Screwdrivers are available—manual, electric, and pneumatic—with a clutch that slips at a preset torque. This helps the user tighten screws to a specified torque without damage or over-tightening. Cordless drills designed to use as screwdrivers often have such a clutch.
Powered screwdrivers
Interchangeable bits allow the use of powered screwdrivers, commonly using an electric or air motor to rotate the bit.
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A rechargeable battery-powered electric screwdriver
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Compact electric screwdriver with extended bit
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Cordless drill being used to drive screw fastener
Ratcheting screwdrivers
Some manual screwdrivers have a ratchet action whereby the screwdriver blade locks to the handle for clockwise rotation, but uncouples for counterclockwise rotation when set for tightening screws—and vice versa for loosening.
Spiral ratchet screw drivers, often colloquially called
Once very popular, versions of these spiral ratchet drivers using proprietary bits have been largely discontinued by manufacturers such as Stanley. Some companies now offer a modernized version that uses standard 1⁄4-inch hex shank power tool bits. Since a wide variety of drill bits are available in this format, the tool can do double duty as a "push drill" or Persian drill.
See also
References
Citations
- ^ "Screwdriver | tool". Encyclopedia Britannica. Archived from the original on 2013-12-19. Retrieved 2013-12-18.
- ^ "Schraubenzieher « atlas-alltagssprache". Archived from the original on 2021-08-20. Retrieved 2021-08-09.
- ^ "Franz Kafka: In der Strafkolonie". Archived from the original on 2021-08-09. Retrieved 2021-08-09.
- ^ "Schraubenzieher". Archived from the original on 2021-08-06. Retrieved 2021-08-09.
- ^ Rybczynski 2000, pp. 90–94.
- from the original on 2017-02-16.
- ISBN 978-0-375-76430-1.
- ISBN 978-0-7607-2719-5. Retrieved 27 September 2018.
- ^ Richards, A.J.; Stephenson, J.H. (1984). Avionic Navigation Systems Specialist. Extension Course Institute, Air University. p. 169. Archived from the original on 30 May 2020. Retrieved 27 September 2018.
- ^ "The 10 Best Screwdriver Sets of 2023, Tested and Reviewed". 15 April 2020.
- hdl:10919/36701.
- ^ U.S. patent 2,474,994
- ^ US 2474994, Tomalis, Joseph & American Screw Company, "Screw Socket", published December 30, 1942, issued July 5, 1949
- ^ "US Patent #2,474,994 Claims, Page 7". Archived from the original on 2017-08-04.
- ISBN 978-1-892836-17-5. Archivedfrom the original on 2013-10-11. Retrieved 2012-03-12.
- ^ Robertson Inc. "Robertson Inc. - The Original Robertson Fastening System". Robertson Inc. main site. Archived from the original on 2011-09-26. Retrieved 2011-09-28.
- ^ Rybczynski 2000, pp. 79–81.
- ^ a b c Rybczynski 2000, pp. 85–86
- ^ "The Phillips screwdriver has about 30° flukes and a blunt end, while the Reed and Prince has 45° flukes and a sharper, pointed end." RECESSED www.tpub.com Archived 2009-04-08 at the Wayback Machine October 2011
- ISBN 978-0-240-81291-5. Archivedfrom the original on 2014-07-07. Retrieved 2014-09-14.
- ^ "Bits From MRO Tools". mrotools.com. Archived from the original on 2012-04-25.
The Frearson recess is designed so that any size bit will fit any size recess.
- ^ "When a Phillips is not a Phillips, step13: Posidriv". instructibles.com. Archived from the original on 2014-09-03.
- ^ "When a Phillips is not a Phillips, step10: JIS – Japanese Industrial Standard". instructibles.com. October 2011. Archived from the original on 2011-08-27.
Works cited
- OCLC 462234518. Various republications (paperback, e-book, braille, etc).