Editing Screwdriver (section)

== Drive tip ==
{{Main|List of screw drives}}
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.

{{anchor|Bit|Microbit}}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 bit]]s. This provides a set of one handle and several bits that can drive a variety of screw sizes and types.

<gallery mode=packed>
File:Jeweler's screwdriver.jpg|A jeweler's screwdriver
File:Magnetschraubendreher IMGP1940.jpg|Screwdriver with magnetic tip
</gallery>

===Slotted===
[[File:Big flat screwdriver.jpg|thumb|Screwdriver with rubber handle]]
The tool used to drive a '''slotted''' screw head is called a ''standard'', ''common blade'', ''flat-blade'', ''slot-head'', ''straight'', ''flat'', ''flat-tip'',<ref name="capotosto">{{Citation |last=Capotosto |first=Rosario |title=Screwdriver Basics |journal=[[Popular Mechanics]] |volume=173 |issue=12 |pages=82–83 |date=December 1996 |url=https://books.google.com/books?id=R2YEAAAAMBAJ&pg=PA82 |issn=0032-4558 |postscript=. |url-status=live |archive-url=https://web.archive.org/web/20170216031252/https://books.google.com/books?id=R2YEAAAAMBAJ&pg=PA82 |archive-date=2017-02-16 }}</ref> or "''flat-head''"<ref>{{cite book |last=Review |first=Princeton |title=Cracking the ASVAB |publisher=Random House |location=New York |year=2004 |page=[https://archive.org/details/crackingasvab00prin/page/174 174] |url=https://archive.org/details/crackingasvab00prin |url-access=registration |isbn=978-0-375-76430-1 }}</ref> 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 [[countersink|countersunk hole]].  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";<ref name="Chilton 2001">{{cite book |last=Chilton |first=G. |title=Homebasics: the complete guide to running today's home |publisher=Barnes & Noble Books |year=2001 |isbn=978-0-7607-2719-5 |url=https://archive.org/details/homebasicscomple0000chil |url-access=registration |access-date=27 September 2018 |page=[https://archive.org/details/homebasicscomple0000chil/page/18 18]}}</ref> within the avionics and mining industries, it is known as a "standard screwdriver".<ref name="Richards Stephenson 1984">{{cite book |last1=Richards |first1=A.J. |last2=Stephenson |first2=J.H. |title=Avionic Navigation Systems Specialist |publisher=Extension Course Institute, Air University |year=1984 |url=https://books.google.com/books?id=NZTgrJRYYPQC |access-date=27 September 2018 |page=169 |archive-date=30 May 2020 |archive-url=https://web.archive.org/web/20200530010403/https://books.google.com/books?id=NZTgrJRYYPQC |url-status=live }}</ref> Though there are many names; the original device from 1908 was known as a "flat-head screw turner".{{citation needed|date=August 2017}}

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|date=January 2023}} 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 hardening|induction-hardened]] (surface heat-treated), coated with black-oxide, black-phosphate, or diamond-coated to increase friction between the screwdriver tip and the screw.<ref>{{cite web | url=https://www.bobvila.com/articles/best-screwdriver-set/#:~:text=Black-oxide%2C%20black-phosphate%2C%20and%20diamond-coated%20tips%20increase%20friction%20between,their%20increased%20grip%20strength%20when%20driving%20a%20screw | title=The 10 Best Screwdriver Sets of 2023, Tested and Reviewed | date=15 April 2020 }}</ref> 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.<ref>{{cite thesis |degree=Master's |title=Testing and Understanding Screwdriver Bit Wear |date=1998-05-18 |publisher=Virginia Tech |last=Adler |first=Alexander |hdl=10919/36701 |hdl-access=free}}</ref> However, a subsequent refinement to the original design described in US Patent #2,474,994<ref>{{US Patent| 2474994}}</ref><ref>{{Cite patent |inventor-last=Tomalis |inventor-first=Joseph |inventor2-last=American Screw Company |publication-date=December 30, 1942 |issue-date=July 5, 1949 |title=Screw Socket |country-code=US |patent-number=2474994}}</ref><ref>{{cite web |url=http://pdfpiw.uspto.gov/.piw?PageNum=7&docid=02474994&IDKey=14D96AF311E8&HomeUrl=http%3A%2F%2Fpatft.uspto.gov%2Fnetacgi%2Fnph-Parser%3FSect2%3DPTO1%2526Sect2%3DHITOFF%2526p%3D1%2526u%3D%2Fnetahtml%2FPTO%2Fsearch-bool.html%2526r%3D1%2526f%3DG%2526l%3D50%2526d%3DPALL%2526S1%3D2474994.PN.%2526OS%3DPN%2F2474994%2526RS%3DPN%2F2474994 |title=US Patent #2,474,994 Claims, Page 7 |url-status=live |archive-url=https://web.archive.org/web/20170804055028/http://pdfpiw.uspto.gov/.piw?PageNum=7&docid=02474994&IDKey=14D96AF311E8&HomeUrl=http%3A%2F%2Fpatft.uspto.gov%2Fnetacgi%2Fnph-Parser%3FSect2%3DPTO1%2526Sect2%3DHITOFF%2526p%3D1%2526u%3D%2Fnetahtml%2FPTO%2Fsearch-bool.html%2526r%3D1%2526f%3DG%2526l%3D50%2526d%3DPALL%2526S1%3D2474994.PN.%2526OS%3DPN%2F2474994%2526RS%3DPN%2F2474994 |archive-date=2017-08-04 }}</ref> describes this feature.

=== Robertson ===
{{See also|Robertson screw}}
[[File:Robertson screwdrivers.jpg|thumb|A variety of Robertson sizes]]
'''Robertson''', also known as a '''square''',<ref>{{cite book |url=https://books.google.com/books?id=qWYVk7lSsN4C&pg=PA107 |title=Furniture Projects for the Deck and Lawn |publisher=Cambium Press |date=2004 |access-date=2012-03-12 |isbn=978-1-892836-17-5 |url-status=live |archive-url=https://web.archive.org/web/20131011223753/http://books.google.com/books?id=qWYVk7lSsN4C&pg=PA107 |archive-date=2013-10-11 }}</ref> or '''Scrulox'''<ref>{{cite web |last=Robertson Inc. |title=Robertson Inc. - The Original Robertson Fastening System |url=http://www.robertsonscrew.com/ |work=Robertson Inc. main site |access-date=2011-09-28 |url-status=live |archive-url=https://web.archive.org/web/20110926201148/http://www.robertsonscrew.com/ |archive-date=2011-09-26 }}</ref>  screw drive has a [[Square (geometry)|square]]-shaped socket in the screw head and a square protrusion on the tool. Both the tool and the socket have a taper, which makes inserting the tool easier, and also tends to help keep the screw on the tool tip. (The taper's earliest reason for being was to make the manufacture of the screws practical using [[cold forming]] of the heads,<ref name="Rybczynski2000pp79-81">{{Harvnb|Rybczynski|2000|pp=79–81}}.</ref> but its other advantages helped popularize the drive.) Robertson screws are commonplace in [[Canada]], though they have been used elsewhere,<ref name="Rybczynski2000pp85-86">{{Harvnb|Rybczynski|2000|pp=85–86}}</ref> and have become much more common in other countries in recent decades. Robertson screwdrivers are easy to use one-handed, because the tapered socket tends to retain the screw, even if it is shaken.<ref name="Rybczynski2000pp85-86" /> They also allow for the use of angled screw drivers and trim head screws. The socket-headed Robertson screws are self-centering, reduce cam out, stop a power tool when set, and can be removed if painted over or old and rusty.<ref name="Rybczynski2000pp85-86" /> In industry, they speed up production and reduce product damage.  One of their first major industrial uses was the Ford Motor Company's Model A & Model T production.  Henry Ford found them highly reliable and saved considerable production time, but he could not secure licensing for them in the United States, so he limited their use solely to his Canadian division. Robertson-head screwdrivers are available in a standard range of tip sizes, from 1.77mm to 4.85mm.

===Reed and Prince===
[[File:Frearson vs Phillips.svg|thumb|upright|Comparison of Phillips and Frearson screw heads]]
'''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.<ref>"The Phillips screwdriver has about 30° flukes and a blunt end, while the Reed and Prince has 45° flukes and a sharper, pointed end."  [http://www.tpub.com/content/aviation/14001/css/14001_39.htm RECESSED www.tpub.com] {{webarchive|url=https://web.archive.org/web/20090408004919/http://www.tpub.com/content/aviation/14001/css/14001_39.htm |date=2009-04-08 }} October 2011</ref><ref>{{cite book |url=https://books.google.com/books?id=Lnpf1TcuH7IC&q=reed+prince+screwdriver+degree&pg=PA135 |title=The Grip Book |author=Michael Uva |publisher=Taylor & Francis |year=2010 |isbn=978-0-240-81291-5 |access-date=2014-09-14 |url-status=live |archive-url=https://web.archive.org/web/20140707075955/http://books.google.com/books?id=Lnpf1TcuH7IC&pg=PA135&lpg=PA135&dq=reed+prince+screwdriver+degree&source=bl&ots=DQ3IxZxuZQ&sig=tP57CRP7AQX8vm72K2vRr435X5Y&hl=en&ei=AMitTrmhBZLRiAKBkvWABA&sa=X&oi=book_result&ct=result&resnum=1&ved=0CCwQ6AEwAA#v=onepage&q=reed%20prince%20screwdriver%20degree&f=false |archive-date=2014-07-07 }}</ref> In theory, different size R&P screws fit any R&P bit size.<ref>{{cite web |quote=The Frearson recess is designed so that any size bit will fit any size recess. |url=http://mrotools.com/apex-frearson-reed-and-prince-screwdriver-bits.aspx |title=Bits From MRO Tools |website=mrotools.com |url-status=live |archive-url=https://web.archive.org/web/20120425134342/http://mrotools.com/apex-frearson-reed-and-prince-screwdriver-bits.aspx |archive-date=2012-04-25 }}</ref>

===Pozidriv===
[[File:PHILLIPS and POZIDRIV screwdrivers and screw.JPG|thumb|Phillips and Pozidriv compared]]
'''Pozidriv''' and the related '''Supadriv''' are widely used in Europe and most of the Far East.<ref>{{cite web |url=http://www.instructables.com/id/When-a-Phillips-is-not-a-Phillips/step13/Posidriv/ |title=When a Phillips is not a Phillips, step13: Posidriv |website=instructibles.com |url-status=live |archive-url=https://web.archive.org/web/20140903151750/http://www.instructables.com/id/When-a-Phillips-is-not-a-Phillips/step13/Posidriv/ |archive-date=2014-09-03 }}</ref>  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.<ref>{{cite web |url=http://www.instructables.com/id/When-a-Phillips-is-not-a-Phillips/step10/JIS-Japanese-Industrial-Standard/ |title=When a Phillips is not a Phillips, step10: JIS – Japanese Industrial Standard |website=instructibles.com |date=October 2011 |url-status=live |archive-url=https://web.archive.org/web/20110827090123/http://www.instructables.com/id/When-a-Phillips-is-not-a-Phillips/step10/JIS-Japanese-Industrial-Standard |archive-date=2011-08-27 }}</ref>

===Other types===
[[File:Set of security screw driver bits.jpg|thumb|A set of "secure" or otherwise less common screwdriver bits, including secure Torx and secure hex or "Allen" variants]]
Many modern [[electrical appliance]]s, if they contain screws, use screws with heads other than the typical slotted or Phillips styles.  '''[[Torx]]''' is one such pattern that has become widespread. It is a spline tip with a corresponding recess in the screw head.  The main cause of this trend is manufacturing efficiency: Torx screwdriver tips do not slip out of the fastener as easily as would a Phillips or slotted driver.

Non-typical fasteners are commonplace in consumer devices for their ability to make disassembly more difficult. In microwave ovens, such screws deny casual access to the high-power kilovolt electrical components.

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.