Editing Knife (section)

====Folding blade features====
[[File:Swiss army knife open 20050612 (cropped).jpg|thumb|alt=Folding pocket knife with multiple exposed tools|A [[Swiss Army knife]]]]
{{Main|Pocketknife}}
A folding knife connects the blade to the handle through a [[Lever|pivot]], allowing the blade to fold into the handle. To prevent injury to the knife user through the blade accidentally closing on the user's hand, folding knives typically have a locking mechanism. Different locking mechanisms are favored by various individuals for reasons such as perceived strength (lock safety), legality, and ease of use.
Popular locking mechanisms include:
* ''Slip joint'' – Found most commonly on traditional pocket knives, the opened blade does not lock, but is held in place by a spring device that allows the blade to fold if a certain amount of pressure is applied.<ref name="Kertzman2013sj">{{cite book|last=Kertzman|first=Joe|title=Knives 2014: The World's Greatest Knife Book|url=https://books.google.com/books?id=wS7UAAAAQBAJ&pg=PA7|year=2013|publisher=F+W Media|location=Iola, WI|isbn=978-1-4402-3700-3|page=7}}</ref>
* ''Lockback'' – Also known as the ''spine lock'', the lockback includes a pivoted latch affixed to a spring, and can be disengaged only by pressing the latch down to release the blade.
* ''[[Walker Linerlock|Linerlock]]'' – Invented by [[Michael Walker (knifemaker)|Michael Walker]], a Linerlock is a folding knife with a side-spring lock that can be opened and closed with one hand without repositioning the knife in the hand. The lock is self-adjusting for wear.<ref name=winter>{{cite book|last=Warner|first= Ken|title=Knives 91|date=1991|page =31}}</ref>
* ''Compression Lock'' – A variant of the Liner Lock, it uses a small piece of metal at the tip of the lock to lock into a small corresponding impression in the blade. This creates a lock that does not disengage when the blade is torqued, instead of becoming more tightly locked. It is released by pressing the tab of metal to the side, to allow the blade to be placed into its groove set into the handle.<ref name=winter/>
* ''Frame Lock'' – Also known as the ''integral lock'' or ''monolock'', this locking mechanism was invented by a custom knifemaker [[Chris Reeve]] for the [[Sebenza]] as an update to the liner lock. The frame lock works in a manner similar to the liner lock but uses a partial cutout of the actual knife handle, rather than a separate liner inside the handle to hold the blade in place.<ref name="NKM93">Dick, Steven, The National Knife Magazine, "The Chris Reeve Sebenza Folding Hunter", September 1993, pp. 16–18.</ref><ref name="KI2000">Lang, Bud, Knives Illustrated, "Chris Reeve's Classic 2000", April 2000, pp. 22–24.</ref>
* ''Collar lock'' – found on [[Opinel knife|Opinel knives]].<ref name="Media1996">{{cite journal|title=American Woodworker|journal=The American Woodworker. Magazine.|url=https://books.google.com/books?id=MfcDAAAAMBAJ&pg=PA43|date=1996|publisher=New Track Media|page=43|issn=1074-9152}}</ref>
* ''Button Lock'' – Found mainly on automatic knives, this type of lock uses a small push-button to open and release the knife.[[Image:BM-AxisLock.jpg|thumb|alt=Close-up of the pivot joint of a folding knife, showing locking barrel inserted through holes in the handle|The Benchmade Axis Lock mechanism]]
* ''Axis Lock'' – A locking mechanism patented by [[Benchmade|Benchmade Knife Company]] until 2020.<ref>{{cite web | url=https://patents.google.com/patent/US5093995A/en | title=Knife lock mechanism }}</ref> A cylindrical bearing is tensioned such that it will jump between the knife blade and some feature of the handle to lock the blade open.<ref name="Ahern2010">{{cite book|last=Ahern|first=Jerry|title=Gun Digest Buyer's Guide to Concealed-Carry Handguns|url=https://books.google.com/books?id=ulWbH-4xtd8C&pg=PA107|date= 2010|publisher=F+W Media, Inc|location=Iola, WI|isbn=978-1-4402-1767-8|page=107}}</ref>
* ''Arc Lock'' – A locking mechanism exclusively licensed to [[SOG Specialty Knives]]. It differs from an axis lock in that the cylindrical bearing is tensioned by a rotary spring rather than an axial spring.<ref name="ShidelerSigler2008">{{cite book|last1=Shideler|first1=Dan|last2=Sigler|first2=Derrek|title=The Gun Digest Book of Tactical Gear|url=https://books.google.com/books?id=zrG2AgAAQBAJ&pg=PA41|year=2008|publisher=F+W Media|location=Iola, WI|isbn=978-1-4402-2429-4|page=41}}</ref>
* ''Ball Bearing Lock'' – A locking mechanism exclusively licensed to [[Spyderco]]. This lock is conceptually similar to the axis and arc locks but the bearing is instead a [[ball bearing]].<ref name="Suermondt2004">{{cite book|last=Suermondt|first=Jan|title=Illustrated guide to knives|url=https://archive.org/details/illustratedguide0000suer|url-access=registration|year=2004|publisher=Grange Books|isbn=978-1-84013-694-4|page=[https://archive.org/details/illustratedguide0000suer/page/12 12]}}</ref>
* ''Tri-Ad Lock'' – A locking mechanism exclusively licensed to [[Cold Steel (company)|Cold Steel]]. It is a form of lockback which incorporates a thick steel stop pin between the front of the latch and the back of the tang to transfer force from the blade into the handle.<ref name="Kertzman2012-cs">{{cite book|last=Kertzman|first=Joe|title=Knives 2013: The World's Greatest Knife Book|url=https://books.google.com/books?id=wtl1UuSk9GEC&pg=PT553|year=2012|publisher=Krause Publications|location=Iola, WI|isbn=978-1-4402-3064-6|page=553}}</ref>
* ''PickLock'' – A round post on the back base of the blade locks into a hole in a spring tab in the handle. To close, manually lift (pick) the spring tab (lock) off the blade post with your fingers, or in "Italian Style Stilettos" swivel the bolster (hand guard) clockwise to lift the spring tab off the blade post.

Another prominent feature of many folding knives is the opening mechanism. Traditional pocket knives and [[Swiss Army Knife|Swiss Army knives]] commonly employ the nail nick, while modern folding knives more often use a stud, hole, disk, or ''flipper'' located on the blade, all of which have the benefit of allowing the user to open the knife with one hand.

The "wave" feature is another prominent design, which uses a part of the blade that protrudes outward to catch on one's pocket as it is drawn, thus opening the blade; this was patented by [[Ernest Emerson]] and is not only used on many of the Emerson knives, but also on knives produced by several other manufacturers, notably [[Spyderco]] and [[Cold Steel (company)|Cold Steel]].<ref name ="cutler">{{cite journal|last=Shackleford|first= Steve |year=1997|title=Cutler of Fortune|journal=Blade Magazine|issue=10|volume=22|page=50}}</ref>

''Automatic'' or ''[[switchblade]]'' knives open using the stored energy from a spring that is released when the user presses a button or lever or other [[actuator]] built into the handle of the knife. Automatic knives are severely restricted by law in the UK and most American states.<ref name="Inc.1994">{{cite journal|last=Brown|first=Carl|title=Martial Arts Weapon Laws|url=https://books.google.com/books?id=QNADAAAAMBAJ&pg=PA82|volume=32|date=August 1994|journal=Black Belt|pages=82, 112–14|issue=8|issn=0277-3066}}</ref>

Increasingly common are ''[[Assisted opening knife|assisted opening]]'' knives which use springs to propel the blade once the user has moved it past a certain angle. These differ from automatic or switchblade knives in that the blade is not released by means of a button or catch on the handle; rather, the blade itself is the actuator. Most assisted openers use flippers as their opening mechanism. Assisted opening knives can be as fast or faster than automatic knives to deploy.<ref>{{cite book|title=Blade's Guide to Knives & Their Values|first=Steve |last=Shackleford|edition=7|page =232|publisher=Krause Publications|year=2010|isbn=978-1-4402-0387-9}}</ref>

=====Common locking mechanisms=====
[[File:Folding knife locking mechanisms.svg|framed|right]]
In the '''lock back''', as in many folding knives, a stop pin acting on the top (or behind) the blade prevents it from rotating clockwise. A hook on the tang of the blade engages with a hook on the rocker bar which prevents the blade from rotating counter-clockwise. The rocker bar is held in position by a torsion bar. To release the knife the rocker bar is pushed downwards as indicated and pivots around the rocker pin, lifting the hook and freeing the blade.

When negative pressure (pushing down on the spine) is applied to the blade all the stress is transferred from the hook on the blade's tang to the hook on the rocker bar and thence to the small rocker pin. Excessive stress can shear one or both of these hooks rendering the knife effectively useless. Knife company Cold Steel uses a variant of the lock back called the '''Tri-Ad Lock''' which introduces a pin in front of the rocker bar to relieve stress on the rocker pin, has an elongated hole around the rocker pin to allow the mechanism to wear over time without losing strength and angles the hooks so that the faces no longer meet vertically.

The bolt in the '''bolt lock''' is a rectangle of metal that is constrained to slide only back and forward. When the knife is open a spring biases the bolt to the forward position where it rests above the tang of the blade preventing the blade from closing. Small knobs extend through the handle of the knife on both sides allowing the user to slide the bolt backward freeing the knife to close. The '''Axis Lock''' used by knife maker Benchmade is functionally identical to the bolt lock except that it uses a cylinder rather than a rectangle to trap the blade.<ref name="Ahern2010"/> The '''Arc Lock''' by knife maker SOG is similar to the Axis Lock except the cylinder follows a curved path rather than a straight path.<ref name="ShidelerSigler2008"/>

In the '''liner lock''', an L-shaped split in the liner allows part of the liner to move sideways from its resting position against the handle to the centre of the knife where it rests against the flat end of the tang. To disengage, this leaf spring is pushed so it again rests flush against the handle allowing the knife to rotate.<ref name=winter/> A '''frame lock''' is functionally identical but instead of using a thin liner inside the handle material uses a thicker piece of metal as the handle and the same split in it allows a section of the frame to press against the tang.<ref name=winter/>