List of screw drives 1

List of screw drives

Part of a series on

Screw drive typesSlot (regular)

PhillipsPH

Pozidriv (SupaDriv)PZ

Square

Robertson (square)

Hex

Hex socket (Allen)

Security hex socket (pin-in-hex-socket)

TorxT & TX

Security TorxTR

Tri-Wing

Torq-set

Spanner head(Snake-eye)

Double-square

Triple squareXZN

Polydrive

One-way

Spline drive

Double hex

Bristol

Pentalobular

List of screw drives 2

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A screw drive is the system used to turn a screw. At a minimum, it is a feature on the screw that allows torque to beapplied to it. Usually it also involves a mating tool, such as a screwdriver, that is used to turn it. The following headsare categorized based on commonality, with the less common drives being classified as "tamper-resistant".Most heads come in a range of sizes, typically distinguished by a number, such as "Phillips #00" or "Torx T5". Thesesizes do not describe a particular dimension of the drive shape, but are arbitrary designations in the same sense as a"Size 8" shoe or dress.

Common types

External typesExternal drives are characterized by a female tool and a male fastener.

Square

Square This screw drive uses square fastener heads. They can be turned with an adjustable wrench,open-end wrench, or 8- or 12-point sockets. Common in the 19th and early 20th centuries, when it waseasier and thriftier to manufacture than most other drives, it is less common today (although still easyto find) because the external hex is now cost-competitive and allows better access for wrenching

despite nearby obstructions, with fewer degrees of swing on each stroke.

Hex

A hex screw drive uses six-sided fastener heads. The fastener is known as a hex head cap screw. It canbe turned with an adjustable wrench, combination wrench, and 6- or 12-point sockets. The hex drive isbetter than square drive for locations where surrounding obstacles limit wrenching access, becausesmaller wrench-swing arcs can still successfully rotate the fastener.

Pentagon

A pentagon screw drive uses five-sided fastener heads. The fastener is known as a penta screw. Theyrequire a special five-point socket in order to be turned. Water meter covers, natural gas valves, andelectrical cabinets are commonly secured with penta fasteners. It is also common in the U.S. for firehydrants to have valves with a pentagon drive.

Thumbscrew

List of screw drives 3

A thumbscrew is a type of screw drive with either a tall head and ridged orknurled sides, or a key-like flat sided vertical head. They are intended to betightened and loosened by hand, and not found in structural applications.They are sometimes also cut for Phillips head and/or slotted screwdrivers aswell as having the knurl for finger grip. ASME 18.6.8 covers dimensions forType A, shoulder under the head, regular and heavy along with Type B,without shoulder, regular and heavy.

Slotted types

Slot

Slot drive tool and fastener sizes

Blade width Fastener size

3⁄32 in (2.4 mm) 0–1

1⁄8 in (3.2 mm) 2

5⁄32 in (4.0 mm) 3

3⁄16 in (4.8 mm) 4–5

1⁄4 in (6.4 mm) 6–7

5⁄16 in (7.9 mm) 8–10

3⁄8 in (9.5 mm) 12–14

7⁄16 in (11 mm) 16–18

1⁄2 in (13 mm) 18–24

The slot screw drive has a single slot in the fastener head and is driven by a flat-bladed screwdriver. It was the firsttype of screw drive to be developed, and for centuries it was the simplest and cheapest to make. The slotted screw iscommon in simple woodworking applications, but is not often seen in applications where a power tool would be usedbecause a power driver tends to slip out of the head and potentially damage the surrounding material. The tool usedto drive a slot is called a standard, flat-blade, slot-head, flat-tip, or flat-head screwdriver.Flat-head in particular can sometimes be confusing, because the term flat-head is also used to describe a screw witha flat top, designed to be installed in a countersunk hole; such a flat-headed screw may have a slotted, cross, squarerecessed, or combination head, causing further confusion about the terminology.

List of screw drives 4

Cross

A cross-recess screw drive has two slots, oriented perpendicular to each other, in the fastener head; aslotted screwdriver is still used to drive just one of the slots. This type is usually found in cheaplymade roofing bolts and the like, where a thread of 5 mm (0.20 in) or above has a large flattened panhead. The sole advantage is that they provide some measure of redundancy: should one slot be

deformed in service, the second may still be used.

Cruciform typesSee also: cross-slotted, Torq-set and Phillips/squareThe following are screw drives based on a cruciform shape, i.e. a cross shape. Other names for these types of drivesare cross-head and cross-point. (Cross-type slotted screw drives are not considered cruciform because the shape isnot recessed.)

Phillips

Phillips drive tool and fastener sizes

Tool size Fastener size

0 0–1

1 2–4

2 5–9

3 10–16

4 18–24

Created by Henry F. Phillips, the Phillips screw drive was purposely designed to cam out when the screwstalled,Wikipedia:Citation needed to prevent the fastener damaging the work or the head, instead damaging thedriver. This was caused by the relative difficulty in building torque limiting into the early drivers.The American Screw Company of Providence, Rhode Island was responsible for devising a means of manufacturingthe screw, and successfully patented and licensed their method; other screw makers of the 1930s dismissed thePhillips concept because it calls for a relatively complex recessed socket shape in the head of the screw — as distinctfrom the simple milled slot of a slotted type screw.Phillips drive sizes (different from the screw size) are designated 0000, 000, 00, 0, 1, 2, 3, and 4 (by order ofincreasing size).

Frearson

The Frearson screw drive, also known as the Reed and Prince screw drive, is similar to a Phillipsbut the Frearson has a sharp tip and larger angle in the V shape. One advantage over the Phillips driveis that one driver or bit fits all screw sizes. It is often found in marine hardware and requires aFrearson

List of screw drives 5

screwdriver or bit to work properly. The tool recess is a perfect, sharp cross,allowing for higher applied torque, unlike the rounded, tapered Phillips head,which was designed to cam out at high torque. It was developed by anEnglish inventor named Frearson in the 19th century and produced from thelate 1930s to the mid-1970s. The Reed & Prince Mfg. Company ofWorcester, Massachusetts, was put into bankruptcy in 1987 and liquidated in1990. Another entity called Reed & Prince Manufacturing Corporation, nowof Leominster, Massachusetts, purchased some of the assets including thename at the liquidation sale.

French recess

French recess driver bit

Also called BNAE NFL22-070 after its Bureau de Normalisation del'Aéronautique et de l'Espace standard number.

JIS B 1012

The JIS B 1012 is commonly found in Japanese equipment. It looks like aPhillips screw, but is designed not to cam out and will, therefore, be damaged

by a Phillips screwdriver if it is too tight. Heads are usually identifiable by a single dot or an "X" to one side of thecross slot.

Specific "JIS" standardized cruciform-blade screwdrivers are available for this type of screw.

Mortorq

The Mortorq drive, developed by the Phillips Screw Company, is a format used in automotive andaerospace applications. It is designed to be a lightweight, low-profile and high-strength drive, with fullcontact over the entire recess wing reducing risk of stripping.[2]

Pozidriv

The Pozidriv, sometimes purposely misspelled Pozidrive to avoid trademark infringement, screwdrive is an improved version of the Phillips screw drive. They can be unscrewed with a regularPhillips screwdriver. It is jointly patented by the Phillips Screw Company and American ScrewCompany. The name is thought to be a portmanteau of positive drive. Its advantage over Phillips

drives is its decreased likelihood to cam out, which allows greater torque to be applied.[3] In ANSI standards it isreferred to as type IA. It is very similar to, and essentially compatible with, the Supadriv screw drive.

List of screw drives 6

Screws with the Pozidriv head.

Phillips drivers have an intentional angle on the flanks and roundedcorners so they will cam out of the slot before a power tool will twistoff the screw head. The Pozidriv screws and drivers have straight sidedflanks.The Pozidriv screwdriver and screws are also visually distinguishablefrom Phillips by the second set of radial indentations set 45 degreesfrom the cross recess. The manufacturing process for Pozidrivscrewdrivers is slightly more complex. The Phillips driver has foursimple slots cut out of it, whereas in the Pozidriv each slot is the resultof two machining processes at right angles. The result of this is that thearms of the cross are parallel-sided with the Pozidriv, and tapered with the Phillips.This design is intended to decrease the likelihood that the Pozidriv screwdriver will slip out, provide a greaterdriving surface, and decrease wear. The chief disadvantage of Pozidriv screws is that they are visually quite similarto Phillips, thus many people are unaware of the difference or do not own the correct drivers for them, and useincorrect screwdrivers. This results in difficulty with removing the screw and damage to the recess, rendering anysubsequent use of a correct screwdriver unsatisfactory. Phillips screwdrivers will fit in and turn Pozidriv screws, butwill cam out if enough torque is applied, potentially damaging the screw head. The drive wings on a Pozidrivscrewdriver will not fit a Phillips screw correctly, and are likely to slip or tear out the screw head.

Supadriv

The Supadriv (sometimes found incorrectly as "Supadrive") screw drive is very similar in functionand appearance to Pozidriv—indeed, the two are often thought to be identical—and is a laterdevelopment by the same company. The description of the Pozidriv head applies also to Supadriv.While each has its own driver, the same screwdriver heads may be used for both types without

damage; for most purposes it is unnecessary to distinguish between the two drives. Pozidriv and Supadriv screws areslightly different in detail; the later Supadriv allows a small angular offset between the screw and the screwdriver,while Pozidriv has to be directly in line.[4][5]

In detail, the Supadriv screwhead is similar to Pozidriv but has only two identification ticks, and the secondaryblades are larger. Drive blades are about equal thickness. The main practical difference is in driving screws intovertical surfaces: that close to a near vertical surface to drive the screws into the drivers, Supadriv has superior bite,making screwdriving more efficient, with less cam out.

Robertson

A Robertson, also known as a square, or Scrulox screw drive has a square-shaped socket in thescrew head and a square protrusion on the tool. Both the tool and the socket have a taper, which makesinserting the tool easier, and also tends to help keep the screw on the tool tip without the user needingto hold it there. (The taper's earliest reason for being was to make the manufacture of the screws

practical using cold forming of the heads, but its other advantages helped popularize the drive.) Robertson screws arecommonplace in Canada, though they have been used elsewhere and have become much more common in othercountries in recent decades. Robertson screwdrivers are easy to use one-handed, because the tapered socket tends toretain the screw, even if it is shaken. They also allow for the use of angled screw drivers and trim head screws. Thesocket-headed Robertson screws are self-centering, reduce cam out, stop a power tool when set, and can be removedif painted-over or old and rusty. In industry, they speed up production and reduce product damage.

List of screw drives 7

Close-up of aRobertson screw

The internal-wrenching square socket drive for screws (as well as the corresponding triangularsocket drive) was conceived several decades before the Canadian P. L. Robertson invented theRobertson screw and screwdriver in 1908 and received patents in 1909 (Canada) and 1911(U.S. Patent 1,003,657 [6]). An earlier patent covering both square-socket- andtriangle-socket-drive wood screws, U.S. Patent 161,390 [7], was issued to one AllanCummings of New York City on March 30, 1875. However, as with other clever drive typesconceived and patented in the 1860s through 1890s, it was not manufactured widely (if at all)during its patent lifespan due to the difficulty and expense of doing so at the time. Robertson'sbreakthrough in 1908 was to design the socket's taper and proportions in such a combinationthat the heads could be easily and successfully cold formed, which is what made such screws avalid commercial proposition. Today cold forming (via stamping in a die) is still the commonmethod used for most screws sold, although rotary broaching is also common now. Linearbroaching to cut corners into a drilled hole (similar to the action of a mortising machine for woodworking) has alsobeen used (less commonly) over the decades.

Robertson had licensed the screw design to a maker in England, but the party that he was dealing with intentionallydrove the company into bankruptcy and purchased the rights from the trustee, thus circumventingRobertson.Wikipedia:Citation needed He spent a small fortune buying back the rights. Subsequently, he refused toallow anyone to make the screws under license. When Henry Ford tried out the Robertson screws he found theysaved considerable time in Model T production, but when Robertson refused to license the screws to Ford, Fordrealized that the supply of screws would not be guaranteed and chose to limit their use in production to Ford'sCanadian division. Robertson's refusal to license his screws prevented their widespread adoption in the UnitedStates, where the more widely licensed Phillips head has gained acceptance. The restriction of licensing ofRobertson's internal-wrenching square may have sped the development of the internal-wrenching hexagon, althoughdocumentation of this is limited.Robertson-head screwdrivers are available in range of tip-sizes. A given driver's suitability for use with a particularsize of screw and recess size is indicated upon its handle according to the following color code:

Color Screw types Fraction Range

Orange (#00) No. 1 & 2 1/16 in.+ ??

Yellow (#0) No. 3 & 4 3/32 in.- 0.0696–0.071 in (1.77–1.80 mm)

Green (#1) No. 5, 6[8] & 7 7/64 in.+ 0.090–0.091 in (2.3–2.3 mm)

Red (#2) No. 8, 9 & 10 1/8 in.+ 0.111–0.1126 in (2.82–2.86 mm)

Black (#3) No. 12 & 1/4 3/16 in.+ 0.1315–0.133 in (3.34–3.38 mm)

Brown (#4) 5/16 and 3/8 3/16 in.+ 0.1895–0.191 in (4.81–4.85 mm)

|+ style="color:black;" | Recess dimensionsDouble-square and triple-square drives are 2 or 3 squares superimposed (respectively), forming an 8-pointed or12-pointed star. In other words, 2 or 3 Robertson squares superimposed at 45° or 30° rotation. The idea is that it'slike a square (Robertson) but can be caught at more frequent angles by the driver bit.

List of screw drives 8

Close-up of Robertson drivers Illustrationfrom

Robertson'spatent

application

Advertisement: “A Study inEvolution”

US patent161390,

AllanCummings,1875, woodscrew drives

Hex socketMain article: Hex key

Hex socket screws

The hex socket screw drive has a hexagonal recess and may be driven by ahex wrench, also known as an Allen Wrench, Allen key, hex key or inbus aswell as by a hex screwdriver (also known as a hex driver) or bit.Tamper-resistant versions with a pin in the recess are available.

Hexalobular socket

Main article: Torx

The hexalobular socket screw drive, often referred to by the original proprietary brand name Torx(pronounced "torks") or by the alternate generic name star drive, uses a star-shaped recess in thefastener with six rounded points. It was designed to permit increased torque transfer from the driver tothe bit compared to other drive systems. Torx is very popular in the automotive and electronics

industries because of resistance to cam out and extended bit life, as well as reduced operator fatigue by minimizingthe need to bear down on the drive tool to prevent cam out. Torx-Plus is an improved version of Torx that extendstool life even further and permits greater torque transfer compared to Torx. A tamper-resistant Torx head has a smallpin inside the recess. The tamper-resistant Torx is also made in a five-lobed variant. These "5-star" Torxconfigurations are commonly used in correctional facilities, public facilities and government schools, but can also befound in some electronic devices.

The drive was developed in 1967[9] by Camcar Textron.[10]

TTAP

Main article: TTAPTTAP is an improved hexalobular screw drive that reduces wobbling between the fastener and thetool. TTAP is backward compatible with standard hexalobular tools.

List of screw drives 9

Double-square

Double-square drive is 2 squares superimposed, forming an 8-pointed star. In other words, 2Robertson squares superimposed at 45° rotation. The concept is similar to that of the triple-square, theidea being that it's like a square (Robertson) but can be caught at more frequent angles by the driverbit.

Combination drivesSome screws have heads designed to accommodate more than one kind of driver, sometimes referred to ascombo-head or combi-head. The most common of these is a combination of a slotted and Phillips head, often used inattaching knobs to furniture drawer fronts. Because of its prevalence, there are now drivers made specifically for thiskind of screw head. Other combinations are a Phillips and Robertson, a Robertson and a slotted, a torx and a slotted,and a triple-drive screw that can take a slotted, Phillips or a Robertson. The Recex drive system claims it offers thecombined non-slip convenience of a Robertson drive during production assembly and Phillips for after marketserviceability. Quadrex is another Phillips/Robertson drive. Phillips Screw Company offers both Phillips andPozidriv combo heads with Robertson.Wikipedia:Citation neededCombined slotted/pozidriv heads are so ubiquitous in electrical switchgear to have earned the nickname 'electriciansscrews' (the first screwdriver out of the toolbox is used - the user does not have to waste valuable time searching forthe correct driver). Their rise to popular use has been in spite of the fact that neither a flat screwdriver or pozidrivscrewdriver are fully successful in driving these screws to the required torque. Some screwdriver manufacturers offermatching screwdrivers and call them 'contractor screwdrivers', although the original concept of not needing to searchfor a particular driver is defeated as a contractor screwdriver is useless for non-combination heads. Slotted/Phillips(as opposed to slotted/pozidriv) heads occur in some North American made switchgear.Wikipedia:Citation needed

Phillips/square

The Phillips/square screw drive, also known as the Quadrex screw drive, is a combination of thePhillips and Robertson screw drives. While a standard Phillips or Robertson tool can be used, there isalso a dedicated tool for it that increases the surface area between the tool and the fastener so it canhandle more torque. This drive was formerly also sold by Home Depot under the name Deck Mate,

which now signifies another drive.

List of screw drives 10

Slotted/Torx

A combined slotted and Torx drive screw was used in electronics manufacturing, notably Compaq used this type tocombine the benefits of Torx in manufacturing and the commonality of flat drive in field repair situations. The slotwas closed on the ends to avoid the flat blade tool slipping and damaging the electronics.

Tamper-resistant types

A set of "secure" or otherwise less commonscrewdriver bits, including secure Torx and

secure hex or "allen" variants.

Most of the following screw drives are considered tamper-resistantbecause of their obscurity. The exceptions to this are the double hexand triple square screw drives that can be removed with standard hexor square screw bits. The first class of tamper-resistant drives iscommonly used on equipment such as home electronics, to preventeasy access, reducing the incidence of damage or improper repair.Equally this can prevent people with the relevant technical knowledgefrom possibly performing a repair without having to return the unit tothe manufacturer. However, widespread recent availability of assorteddrive bits (including security types) minimizes this advantage, at leastfor some security types. True tamper resistant screw drives include thebreakaway head, one way, TA, and TP3 screw drives.

Breakaway headThe breakaway head is a high-security fastener whose head breaks off during installation, immediately afterdriving, to leave only a smooth surface. It consists of a countersunk flat-head screw, with a thin shank and hex headprotruding from the flat head. The hex head is used to drive the screw into the countersunk hole, then either a wrenchor hammer is used to break the shank and hex head from the flat head—or it is driven until the driving head shearsoff, leaving only a smooth screw head exposed. This type of screw is commonly used in prison door locks,automobile ignition switches, and street signs. This drive type has the disadvantage of not being torque controlled;many applications fail due to either too little torque being applied to correctly fasten the joint, or too much torquebeing required to shear the head, resulting in damage to the material being fastened.Wikipedia:Citation needed

Bristol

The Bristol screw drive is a spline with four or six splines, which are not necessarily tamper resistant.The grooves in the wrench are cut by a square-cornered broach, giving a slight undercut to the outercorners of the driver. The main advantage to this drive system is that almost all of the turning force isapplied at right angles to the fastener spline face, which reduces the possibility of stripping the

fastener. For this reason Bristol screw drives are often used in softer, non-ferrous metals. Compared to an Allendrive, Bristol drives are less likely to strip for the same amount of torque; however the Bristol drive is not muchmore strip resistant than a Torx drive.Wikipedia:Citation needed It was created by the Bristol Wrench Company.

This type of drive is commonly used in avionics, higher-end communications equipment, cameras, air brakes,construction and farm equipment, astronomy, and military equipment. Variants with a pin in the center are oftenfound in video game systems: such as PlayStations, Xboxes, and others.

List of screw drives 11

Clutch

A clutch head screw.

There are two types of clutch screw drives: type A and type G. Type A,also known as a standard clutch resembles a bow tie. These werecommon in GM automobiles, trucks and buses of the 1940s and 1950s.Type G resembles a butterfly. This type of screw head is commonlyused in the manufacture of mobile homes and recreationalvehicles.Wikipedia:Citation needed Type G is not necessarily tamperresistant because type G can be removed with a flat-blade screwdriver.

Claw

Two projections opposite each other.

Double hex

Double hex is a screw drive with a socket shaped as two coaxial offset hexes. Its shape is similar totriple square and spline screw drives, but they are incompatible. Standard hex keys can be used withthese sockets.

The radial 'height' of each arris is reduced, compared to a six-point, although their number is doubled.They are potentially capable of allowing more torque than a six-point, but greater demands are placed on themetallurgy of the heads and the tools used, to avoid rounding off.Wikipedia:Citation needed

Line

The line screw drive is a Japanese system with male, female, and female tamper-resistant screwconfigurations. The fasteners are commonly called line head screws. They are also known as game bitscrews, due to their use on videogame consoles. They are found on IBM computers and Nintendosystems. The female sizes are designated: ALR2, ALR3, ALR4, ALR5, ALR6; the male: ALH2,ALH3, ALH4, ALH5, ALH6; and the tamper-resistant female have a "T" at the end of the designation(e.g. ALR3T).

List of screw drives 12

One-way

A one-way slotted screw

One-way screws are special screws that can only be turned in onedirection. They can be installed with a standard flat-blade screwdriver.One-way screws are commonly used in commercial restroom fixturesand on vehicle registration plates, to prevent vandals from tamperingwith them. One-way screws are only practical when the need forremoval is unlikely. They are difficult to remove with conventionaltools because the slot is designed to cause cam out when even minimaltorque is applied in the direction to unscrew it. Instead, a specialremoval tool (a one-way screw extractor) must be used. Alternatively,a one-way screw can be removed by using a drill bit, by using a rotarytool and cutting disk to extend the slot, by using locking pliers, or bydrilling two holes in the slot and removing the screw with a pinspanner (snake-eyes driver).

Pentalobe

Main article: Pentalobe screw

The pentalobe screw drive (often mistaken for 5-point torx screw drives) is a five-pointedtamper-resistant system being implemented by Apple in its products. Apple's first use of the pentalobedrive was in mid-2009. They used a pentalobe screw to secure the battery in the MacBook Pro;smaller versions are now used on the iPhone 4, the iPhone 4S, the iPhone 5, the MacBook Air, and the

MacBook Pro with Retina display. Inexpensive pentalobe screwdrivers, manufactured by third-parties, are relativelyeasy to obtain. Pentalobe screw sizes include TS1 (0.8mm, used on the iPhone 4, the iPhone 4S and the iPhone 5),TS4 (1.2mm, used on the MacBook Air and the MacBook Pro with Retina display), and TS5 (1.5mm, used on the2009 MacBook Pro battery). The TS designation is ambiguous as it is also used for Torq-set screw drive.

Polydrive

The polydrive screw drive, also known as ribe, is spline shaped with rounded ends in the fastenerhead. The tool has six flat-tip teeth at equal spacing; the sizes are determined by the diameter of thestar points. Its primary advantage over older screw drives is that it resists camming out. It is usedprimarily in the automotive industry in high-torque applications, such as brakes and driveshafts.

List of screw drives 13

Proprietary headThere are specialty fastener companies that make unusual, proprietary head designs, featuring matching driversavailable only from them, and only supplied to registered owners. These tend to be confined to industrial uses thatare unavailable to the average layperson. One example familiar to laypersons is the attachment for the wheels and/orspare tires of some types of car; one of the nuts on each wheel may require a specialized socket, provided with thecar, to deter theft. Security fasteners are also available for bicycle wheels and seats.

Protruding obstacle or pin type

A protruding obstacle screw drive is a common modification to socket and cruciform style drives tomake the fastener more tamper resistant by inserting a pin in the fastener screw drive, requiring a toolwith a corresponding hole to drive the fastener. This can also prevent attempts at turning the screwwith a small flat-bladed screwdriver. Sometimes the hole is slightly off-center.Wikipedia:Citationneeded

Spanner

The spanner[11] or snake eyes (trademarked) screw drive uses two round holes opposite each otherand is designed to prevent tampering. This type is seen in elevators and restrooms in the United States,and also the London Underground in the United Kingdom. The driving tool is called a spanner driveror spanner screwdriver[12] in the U.S. and a pin spanner in the UK.Wikipedia:Citation needed They

are also often used for soft spikes on golf shoes.

The knife and gun manufacturer Microtech uses a variation of this with 3 round holes arranged in a triangle shape.

Spline

The spline screw drive has twelve splines in the fastener and tool. Spline drives are sized via numbers.Its primary advantage is its ability to resist camming out, therefore it is used in high-torqueapplications, such as tamper-proof lug nuts, cylinder head bolts, and other engine bolts.

Torq-set

A set of torq-set bits

Torq-set is a cruciform screw drive used in torque-sensitiveapplications. The Torq-set head is similar in appearance to a Phillipsdrive in that it has a cross with 4 arms. In Torq-set however, the linesare offset from each other, so they do not align to form intersectingslots across the top of the head. Because of this, a regular Phillips orflat-blade screwdriver will not fit the head. It is used in aerospaceapplications, e.g., the B-2 stealth bomber. Phillips Screw Companyowns the name and produces the fasteners.

The applicable standards that govern the Torq-set geometry areNational Aerospace Standard NASM 33781 and NASM 14191 for theribbed version. The ribbed version is also known as ACR Torq-set.

List of screw drives 14

TA

The TA is a type of screw drive that uses a triangle-shaped recess in the screw head. Note that thesides of the triangle are straight, which differs from TP3 fasteners. Sizes include TA18, TA20, TA23,and TA27. These screws are often found in children's toys, particularly from fast food restaurants.They can also be found in devices such as vacuum cleaners, fan heaters, elevators and camping stoves,

among others, to help restrict access to the device internals.

TP3

Oral-B rechargeable toothbrush,showing the TP3 headed screw used to

hold the case together. When therechargeable battery is no longer

serviceable, the toothbrush may bedismantled with this screw and the

battery and motor units sent separatelyfor recycling. The battery charger has a

moulded screwdriver on its case.

TP3 is a type of screw drive that uses a Reuleaux Triangle-shaped recess in thescrew head. It is used on fast food promotional toys and video games, die-casttoys and Roomba battery packs. There are four sizes: A = 2 mm, 2.3 mm,2.7 mm, and 3.2 mm.

Tri-point

First row: Tri-Wing bits and screw head.Beneath: Tri-Point/Y-Type.

The tri-point, security screw head is similar to the Phillips screw head,but it has three points rather than four. These specalized screws areusually used on electronics equipment, including the NintendoGamecube, Nintendo Game Boy Advance, Game Boy Advance SP,Sanyo and Kyocera cellular telephones and Fuji digital cameras.

Tri-wing

The tri-wing, also known as triangular slotted, is a screw with threeslotted "wings" and a small triangular hole in the center. The designwas adapted by some parts of the aerospace industry, led by Lockheedin the early 1970s on the L-1011, but met with mixed results due to complaints of insert damage during installation.McDonnell Douglas also used this as a primary fastener on its commercial aircraft. In the present day it is usuallyused on electronics equipment.

A variation has the three "wings" joined in the center, but with no triangular hole. It is commonly used on Nintendo products. Some Nokia Phone chargers use tri-wing screws. Apple uses this on the 2010 and 2011 Macbook Pro

List of screw drives 15

battery access - Y1 size. Microsoft's Zune also uses this type on some models. Nikon also uses this type of screws onsome equipment like the SB-700 flash.A somewhat similar-looking design where three short radial slots are not joined in the center is called a tri-groovescrew drive. The version with same design but reverseWikipedia:Please clarify threads is called an Opsit screw.

Triple square

6 mm and 8 mm triple square drivers

End view of 10 mm triple square screw

The triple square, also known as XZN, is a type of screw drive with 12equally spaced tips, each with a 90 degree angle. Common sizes are 6, 8, 10,and 12 mm. Its name derives from overlaying three equal squares to form sucha pattern with 12 right-angled tips (a 12-pointed star). In other words, 3Robertson squares superimposed at 30° rotation. The concept is similar to thatof the double-square—in both cases, the idea being that it's like a square(Robertson) but can be caught at more frequent angles by the driver bit. Thesescrews can be removed with standard Robertson bits.

Triple square drives are often used in high-torque applications, such as cylinderhead bolts and drive train components. The heads are hardened and temperedto withstand the driving torque without destroying the star points.

Triple square fasteners are commonly found on German vehicles such as Audi,BMW, Mercedes, Porsche, and Volkswagen.[13]

Alternative categorizations

There are various other ways to categorize screw drives. One way is by shapeof the fastener screw drive:•• External

•• Hex•• Line (ALH)•• Square

•• Socket heads•• Bristol

•• Clutch•• Double hex•• Hex socket•• Hexalobular socket•• Line (ALR)•• Polydrive•• Robertson•• Spline•• TP3•• Triple square

List of screw drives 16

Notes[1] http:/ / en. wikipedia. org/ w/ index. php?title=Template:Screw_drives& action=edit[2] Phillips Screw Company (http:/ / www. phillips-screw. com/ Comm_Auto_mortorq_super. htm)[3] Pozidriv page (http:/ / www. phillips-screw. com/ pozidriv. php) at Phillips Screw Company[4] Difference between Pozidriv and Supadriv (in German) (http:/ / www. mindrup. de/ atos/ online/ 9704/ pozidriv. htm)[5] (http:/ / boards. fool. co. uk/ Message. asp?mid=11161184& sort=whole): "Supadrive allow a small angular offset between the screw and the

screwdriver. Pozidrive have to be directly in line"[6] http:/ / www. google. com/ patents/ US1003657[7] http:/ / www. google. com/ patents/ US161390[8][8] Some specialty #6 Robertson screws require a Red #2 driver.[9][9] filed 1967-03-21[10] Camcar eventually became part of Textron Fastening Systems in the 1990s. In 2006 Textron Fastening Systems was sold to Platinum

Equities, LLC, of Beverly Hills, California. They renamed the company Acument Global Technologies (http:/ / www. acument. com/ ), whichas of 2010 includes Avdel, Camcar, Ring Screw, and others.

[11][11] Needs login

[12][12] Needs login

[13] GermanAutoParts.com Volkswagen Tools (http:/ / www. germanautoparts. com/ Tools/ Volkswagen)

References

Bibliography• Rybczynski, Witold (2000), One good turn: a natural history of the screwdriver and the screw, Scribner,

ISBN 978-0-684-86729-8, LCCN  00036988 (http:/ / lccn. loc. gov/ 00036988), OCLC  462234518 (http:/ /www. worldcat. org/ oclc/ 462234518). Various republications (paperback, e-book, braille, etc).

External links• Very comprehensive illustrated and annotated list of screw drive variants (http:/ / www. instructables. com/ id/

When-a-Phillips-is-not-a-Phillips-Plus-So-Much-Mor/ )• Phillips or Pozidriv? (http:/ / www. justbrits. com/ pozi/ pozidriv. html)• Spanner Jaw Sizes (http:/ / www. sat. dundee. ac. uk/ ~psc/ spanner_jaw. html)• Security Fasteners at the University of Wyoming, featuring an extensive list of fastener insert designs (http:/ / w3.

uwyo. edu/ ~jimkirk/ sfast. html)

Article Sources and Contributors 17

Article Sources and ContributorsList of screw drives  Source: http://en.wikipedia.org/w/index.php?oldid=610132585  Contributors: Adamlamee, Alan Liefting, Altaïr, Andy Dingley, ApostropheSheriff, Arthena, Ayeroxor,BrianRecchia, Cabonet, Calvados, Calwiki, Carto308, Catsmeat, Ccgrimm, Ccyg8774, ChrisGualtieri, ChrisHodgesUK, Cloudbound, Coronium, Cpetty-wiki, Cransdell, Crusius2, DMacks,Davefoc, Despatche, Destynova, Dewritech, Dhollm, DocWatson42, Doors International, Dthomsen8, Dtvjho, Ebehn, Edo248, Eric Kvaalen, Flippers, Freckelz43x, GoingBatty, Harryzilber,HodaeeP, Hooperbloob, Inductiveload, Jack mcslay, Jamesx12345, Jdcrutch, Jetpack man, John W. Kennedy, JohnBlackburne, Jonpatterns, Jrvz, Jsaun, Junkyardsparkle, KDS4444,KLWhitehead, Kcdelagarza, KeywordExp, Khazar2, KylieTastic, Lotje, MarmotteNZ, Mattgirling, Mdann52, Michael Minh, Mifield, Mimarx, Modal Jig, Moe Epsilon, Mortense, Mpk, Mufka,Niceguyedc, Nikevich, Nomx7, Nsoranzo, Officiallyover, Oknazevad, Ospalh, P924 CarreraGTS, Pdrake007, Penmachine, Peyre, Piast93, Pol098, Qkasim, R'n'B, RMB1987, Rackham,Raymondwinn, Reify-tech, Rhowryn, Ruudjah2, Ryan8374, Salmanazar, Schneelocke, SixSix, Sm53629, Stillnotelf, Sturmovik, Sumanch, TEXHNK77, TechMaker, Temdor, The PIPE,Theothor32, Three-quarter-ten, Thumperward, Tynam, Tzingca, Ukexpat, Vmkcheat, Voidxor, Vrenator, Webwizard, Why Not A Duck, Whywhenwhohow, Widr, Wikigwil, Wikiuser100,Wizard191, Xen 1986, Yahya Abdal-Aziz, Zmcquaid, 220 anonymous edits

Image Sources, Licenses and ContributorsFile:Screw Head - Slotted.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Screw_Head_-_Slotted.svg  License: unknown  Contributors: Inductiveload, SarangFile:Screw Head - Phillips.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Screw_Head_-_Phillips.svg  License: Public Domain  Contributors: InductiveloadFile:Screw Head - Pozidrive.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Screw_Head_-_Pozidrive.svg  License: Public Domain  Contributors: InductiveloadFile:Screw Head - Square External.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Screw_Head_-_Square_External.svg  License: Public Domain  Contributors: InductiveloadFile:Screw Head - Robertson.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Screw_Head_-_Robertson.svg  License: Public Domain  Contributors: InductiveloadFile:Screw Head - Hex External.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Screw_Head_-_Hex_External.svg  License: Public Domain  Contributors: InductiveloadFile:Screw Head - Hex Socket.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Screw_Head_-_Hex_Socket.svg  License: Public Domain  Contributors: InductiveloadFile:Pin-in-hex socket screw drive 003.png  Source: http://en.wikipedia.org/w/index.php?title=File:Pin-in-hex_socket_screw_drive_003.png  License: Creative Commons Attribution-Sharealike3.0  Contributors: User:Three-quarter-tenFile:Screw Head - Torx.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Screw_Head_-_Torx.svg  License: Public Domain  Contributors: InductiveloadFile:Screw_Head_-_Torx Tamperproof.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Screw_Head_-_Torx_Tamperproof.svg  License: Public Domain  Contributors:InductiveloadFile:Screw Head - Tri-wing.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Screw_Head_-_Tri-wing.svg  License: Public Domain  Contributors: InductiveloadFile:Screw Head - Torq-set.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Screw_Head_-_Torq-set.svg  License: Public Domain  Contributors: InductiveloadFile:Screw Head - Spanner.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Screw_Head_-_Spanner.svg  License: Public Domain  Contributors: InductiveloadFile:Double-square screw drive 001.png  Source: http://en.wikipedia.org/w/index.php?title=File:Double-square_screw_drive_001.png  License: Creative Commons Attribution-Sharealike 3.0 Contributors: User:Three-quarter-tenFile:Screw Head - Triple Square.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Screw_Head_-_Triple_Square.svg  License: Public Domain  Contributors: InductiveloadFile:Screw Head - Polydrive.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Screw_Head_-_Polydrive.svg  License: Public Domain  Contributors: InductiveloadFile:Screw Head - One-way Clutch.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Screw_Head_-_One-way_Clutch.svg  License: Public Domain  Contributors: InductiveloadFile:Screw Head - Spline.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Screw_Head_-_Spline.svg  License: Public Domain  Contributors: InductiveloadFile:Screw Head - Double Hex.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Screw_Head_-_Double_Hex.svg  License: Public Domain  Contributors: InductiveloadFile:Screw Head - Bristol.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Screw_Head_-_Bristol.svg  License: Public Domain  Contributors: InductiveloadFile:Pentalobular.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Pentalobular.svg  License: Creative Commons Attribution 3.0  Contributors: Ruudjah2File:Regular pentagon.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Regular_pentagon.svg  License: Public Domain  Contributors: User:Gustavb/regular_polygon.plFile:Thumbscrews pc.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Thumbscrews_pc.jpg  License: Creative Commons Attribution-Sharealike 2.5  Contributors: Bloodshedder,GreyCatFile:Screw head - cross.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Screw_head_-_cross.svg  License: unknown  Contributors: derivative work:File:Screw Head - Frearson.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Screw_Head_-_Frearson.svg  License: Public Domain  Contributors: InductiveloadFile:Frearson vs Phillips.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Frearson_vs_Phillips.svg  License: Public Domain  Contributors: Original uploader was Doodle77 aten.wikipedia Later versions were uploaded by Sakurambo at en.wikipedia.File:BNAE driver bit.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:BNAE_driver_bit.jpg  License: Public Domain  Contributors: SDCFile:Screw Head - Mortorq.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Screw_Head_-_Mortorq.svg  License: Public Domain  Contributors: InductiveloadFile:Schnellbauschrauben Pozidriv IMGP0880.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Schnellbauschrauben_Pozidriv_IMGP0880.jpg  License: unknown  Contributors:SmialFile:Screw Head - Supadrive.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Screw_Head_-_Supadrive.svg  License: Public Domain  Contributors: InductiveloadFile:Robertson screw.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Robertson_screw.jpg  License: GNU Free Documentation License  Contributors: User:SaforrestFile:robertson screwdrivers.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Robertson_screwdrivers.jpg  License: Public Domain  Contributors: User:Matt DeresFile:Robertson screwdriver patent illustration.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Robertson_screwdriver_patent_illustration.jpg  License: Public Domain Contributors: Library and Archives Canada, Collections Canada website; from Ken Lamb (1998), P.L., inventor of the Robertson screw, Milton Historical Society. ISBN 0969562969.; originalillustration Peter L. Robertson, 1909File:Robertson screw ad.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Robertson_screw_ad.jpg  License: Public Domain  Contributors: Library and Archives Canada, CollectionsCanada website; from Ken Lamb (1998), P.L., inventor of the Robertson screw, Milton Historical Society. ISBN 0969562969.; original illustration Peter L. Robertson, 1909File:US patent 161390 Allan Cummings 1875 wood screw drives.png  Source:http://en.wikipedia.org/w/index.php?title=File:US_patent_161390_Allan_Cummings_1875_wood_screw_drives.png  License: Public Domain  Contributors: Three-quarter-tenFile:Inbus-sruby.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Inbus-sruby.jpg  License: Public Domain  Contributors: Donarreiskoffer, Julo, Tano4595, WikipediaMasterFile:Screw Head - TTAP.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Screw_Head_-_TTAP.svg  License: Creative Commons Zero  Contributors: User:MarmotteNZFile:Screw Head - Quadrex.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Screw_Head_-_Quadrex.svg  License: Creative Commons Attribution-Sharealike 3.0  Contributors:User:Crusius2File:Set of security screw driver bits.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Set_of_security_screw_driver_bits.jpg  License: Creative Commons Zero  Contributors:User:JunkyardsparkleFile:Screw Head - Clutch Type A.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Screw_Head_-_Clutch_Type_A.svg  License: Public Domain  Contributors: InductiveloadFile:Screw Head - Clutch Type G.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Screw_Head_-_Clutch_Type_G.svg  License: Public Domain  Contributors: InductiveloadFile:Clutch head screw.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Clutch_head_screw.jpg  License: Creative Commons Attribution-Sharealike 3.0  Contributors:User:AdamlameeFile:Screw head - line male.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Screw_head_-_line_male.svg  License: Public Domain  Contributors:Screw_head_-_line_female_tamper.svg: *Screw_head_-_line_female.svg: *Screw_Head_-_Polydrive.svg: Inductiveload derivative work: Wizard191 (talk)File:Screw head - line female.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Screw_head_-_line_female.svg  License: Public Domain  Contributors: Screw_Head_-_Polydrive.svg:Inductiveload derivative work: Wizard191 (talk)

Image Sources, Licenses and Contributors 18

File:Screw head - line female tamper.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Screw_head_-_line_female_tamper.svg  License: Public Domain  Contributors:Screw_head_-_line_female.svg: *Screw_Head_-_Polydrive.svg: Inductiveload derivative work: Wizard191 (talk)File:Screws - tamper resistant slotted.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Screws_-_tamper_resistant_slotted.jpg  License: Public Domain  Contributors: Scott EhardtFile:Torx driver secure.png  Source: http://en.wikipedia.org/w/index.php?title=File:Torx_driver_secure.png  License: Public Domain  Contributors: Scott EhardtFile:TorqSet-Bits.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:TorqSet-Bits.jpg  License: Creative Commons Attribution-Sharealike 3.0  Contributors: Afrank99File:Screw Head - TA.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Screw_Head_-_TA.svg  License: Public Domain  Contributors: InductiveloadFile:Oral-B toothbrush with TP3 screw head.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Oral-B_toothbrush_with_TP3_screw_head.jpg  License: Creative CommonsAttribution-Sharealike 3.0  Contributors: Andy DingleyFile:Screw Head - TP3.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Screw_Head_-_TP3.svg  License: Public Domain  Contributors: InductiveloadFile:Tri-Point screw head.png  Source: http://en.wikipedia.org/w/index.php?title=File:Tri-Point_screw_head.png  License: Public Domain  Contributors: Armbrust, Blurred Lines, 1 anonymouseditsFile:TriWing-and-Y-Type-screwdriver-bits-and-screw-heads.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:TriWing-and-Y-Type-screwdriver-bits-and-screw-heads.jpg  License:Creative Commons Attribution-Sharealike 3.0  Contributors: User:TemdorFile:Triple square screw drivers (6mm and 8mm).jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Triple_square_screw_drivers_(6mm_and_8mm).jpg  License: GNU FreeDocumentation License  Contributors: Beao, Binnyswaa, Convivial, Eplack, Skier Dude, SumanchFile:Triple square screw 10mm (TS10b).jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Triple_square_screw_10mm_(TS10b).jpg  License: GNU Free Documentation License Contributors: Jianhui67, Sumanch, 1 anonymous edits

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