Assisted Opening Knives

Assisted Opening Knives

shrade assisted opening knife image

An assisted-opening knife is a type of folding knife which uses an internal mechanism to finish the opening of the blade once the user has partially opened it using a flipper or thumb-stud attached to the blade. 

Assisted opening knives merge function and speed to create a mechanism that opens a blade as fast and smooth as a switchblade. The difference between automatic knives and spring assisted knives is how the blade is deployed. An automatic knife deploys the blade on its own (no exterior finger force) with a trigger/button. A spring assisted knife needs an external force to engage the spring. When the knife is in the closed position, the blade is held in place by means of torsion springs and an additional blade lock (optional). As the user applies manual pressure to the thumbstud to open the knife, a mechanism such as a torsion spring moves along a track in the liner and rapidly rotates the blade into the open and locked position.

Other trade names for assisted-opening knives are: Forward Action Spring Technology, A/O Knife, Torsion Assist Knife, Assisted Knife, Spring Assist Knife, Spring Assisted Knife, Quick Release, Quick Draw, Alternative Automatic, Outburst, SpeedSafe, Blade Launcher, S.A.T (SOG Assisted Technology), and the Semi-Auto.

Assisted Opening Knives

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1660 Kershaw Leek Knife silver plain Blade handle *New Blem* assisted opener

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Kershaw Leek RED Snap On 1660RAT Flipper Assisted Opening Knife USA 1660RATSO

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Kershaw Leek Flipper Speed Assisted Opening Orange Knife CLAM Pack 1660OR USA

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Kershaw 1600 Chive Assisted Opening Ken Onion Knives Knife New *Blem*

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Kershaw Blur Tanto Blackwash Assisted Opening Knife NEW IN BOX USA 1670TSTBW

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Gerber Highbrow Compact Flat Sage FE Assisted Opening Knife 7Cr Steel 2.8” Blade

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Kershaw Speedsafe Assisted Opening 8Cr13MoV Dagger Blade Folding Pocket Knife

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Kershaw Outright Blue PVD 8Cr13MoV Plain Edge Framelock Tactical Knife 8320

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Gerber Highbrow Compact Urban Blue FE Assisted Opening Knife 7Cr Steel 2.8 Blade

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Smith & Wesson M&P MAGIC Flipper Assisted Opening Knife with Safety Lock SWMP6B

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8100 Kershaw Funxion EMT pocket knife knives Assisted opener

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USMC Combat Master Assisted Open Kukri Huge Folding Pocket Knife UC3367 12 1/2"

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Kershaw Flourish Assisted Opening 8Cr13MoV Blade Folding Flipper Pocket Knife

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SOG Fielder Assisted Open Folding Pocket Knife 5Cr15 G10 FF3002-CP 7.8" Open New

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SOG Reactor Multi-tool Pliers Assisted Knife Drivers Cap Lifter RC1001-CP New

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Kershaw 1670BLK Blur Black Handle Plain Edge Assisted Open Folding Pocket Knife

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SOG FLA1001 Flare Assisted Opening Pocket Knife Black Handle Satin Plain Edge

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KERSHAW "USA" - Black LEEK Assisted SPEEDSAFE Knife w/ SAFETY LOCK KS 1660CKT

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KERSHAW 1336 HALOGEN SPEED SAFE ASSISTED OPENING KNIFE CARBON FIBER

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Kershaw USA KnockOut Sandvik Assisted Opening Olive Green Knife 1870OLBLK

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Zero Tolerance 0300 Assisted Opening Knife Black G-10 (3.75" Black) ZT

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Kershaw BlackWash Amplitude Assisted Open 8Cr13MoV Blade Folding Pocket Knife

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Kershaw Scrambler 8Cr13MoV Assisted Opening Blackwash Blade Folding Pocket Knife

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Kershaw pocket knife SpeedSafe assisted opening Wastin Free Shipping USA

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Kershaw Blur Camo Handle Sandvik SpeedSafe Assisted Opening Knife USA 1670CAMO

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Kershaw USA Link Tanto Stonewash Flipper Speed Assisted Opening Knife Clam 1776T

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Kershaw - Halogen CARBON FIBER Spring Assisted FLIPPER Knife SPEEDSAFE KAI 1336

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Kershaw LARGE Cryo II Tanto Blackwash Speed Assisted Opening Knife 1556TBW

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Kershaw NATRIX Black Flipper SpeedSafe Assisted Opening 4.25" Knife BOX 7007BLK

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Kershaw 1555G10 Cryo Assisted EDC Hunting Pocket Folder Folding Knife

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Gerber Highbrow Compact ONYX FE Assisted Opening Knife 7Cr Stainless 2.8" Blade

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KERSHAW 1660BLKW LEEK BlackWash assisted open linerlock knife 1660BWWM USA NEW!

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KERSHAW 1660 LEEK Speed-Safe assisted open linerlock knife USA

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Gil Hibben Fast EDC Ball Bearing Assisted Opening Hurricane Folding Pocket Knife

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1776GRYBW Kershaw Link Drop Point pocket knife assisted opening New Blem USA

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SOG Trident Assisted Open Arc Lock Knife Plain Edge Tanto Blade

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Kershaw 1336 Halogen Black G10/Carbon Fiber Handle Assisted Open Folding Knife

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Kershaw Speed Bump A/O Folding Knife 1595

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Kershaw 2335 Al Mar AM-3 Black G-10 Assisted Open Satin Finish Plain Edge Knife

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KERSHAW 1660 LEEK Speed-Safe assisted open linerlock knife USA

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Kershaw Dividend Folding Knife 420HC Steel Blade Gray Anodized Aluminum Handle

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ALBATROSS Ball Bearing Assisted Open Pocket Folding Knife D2 Blade G10 Handle

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CRKT Ruger Crack-Shot Assisted Open Tactical Pocket Knife 8Cr13MoV R1201K GRN

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Assisted Opening Knife Reviews

More About Assisted Opening Knives

A common source of confusion for new knife enthusiasts is the difference between a spring assisted knife and a switchblade knife. Even those who are familiar with pocket knives or fixed blade knives often don’t know the difference between a switchblade and an assisted knife. The confusion is easy to understand as in both cases the knife may seem to release from the handle on its own. But when you look more closely at the mechanisms which open each blade, you can quickly see the difference.

Although commonly confused with switchblade knives, a switchblade can be opened automatically simply with the push of a button, but the user of an assisted-opening knife must open it about one-quarter of the way (45°) before the mechanism opens the knife the rest of the way. The difference is important legally; because the blade does not open simply "by the push of a button or by force of gravity" the assisted-opening knife is typically not considered a switchblade, and may escape the restrictions applying to those in many places.

The switchblade, or automatic knife, has a button or a lever which releases the blade. The button or lever releases the tension held by a spring inside the knife handle. When the lever or button is pushed, the tension from the spring releases and launches the blade from the handle and into a locked position. Some switchblades release the blade from the side of the handle like a spring assisted or a folding knife, while others release out the front of handle (Out-the-Front or OTF).  There are very strict laws concerning the ownership and carry of automatic knives, and you should always check local regulations before purchasing to avoid problems.

The spring assisted knife, or assisted opening knife, doesn’t rely on a button or lever for opening. Instead, it uses a spring or torsion bar which doesn’t engage until the knife blade has opening momentum from another source. The best source is obviously human power engaging a thumb stud, thumb hole, thumb disc, or flipper, moving the blade forward until the spring or torsion bar engages and moves the blade open the rest of the way.

The simplest way to tell the difference is whether or not there is a button or lever. An assisted opening knife does not have a button or lever. It has some form of initializing action that requires human effort. Your thumb has to push on a flipper, a thumb stud, a thumb disc, or a thumb hole to start moving the blade. If there is a push button or a slide that releases the blade, that makes it an automatic.

The first assisted opening knife was designed by Blackie Collins in 1995 and was named the "Strut-and-Cut"; it was based on the strut of his Ducati motorcycle. A similar concept was developed three years later by knifemaker Ken Onion with Onion's idea based on a similar mechanism in his Harley Davidson motorcycle. Onion applied for a patent on his design in 1998.


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