How does a Spring Assisted Knife work?

Spring Assisted Knife vs Automatic Knives

If you live in an area that restricts the use and carry of automatic knives you may want to consider a spring assisted knife. These knives differ from automatic knives in that you use your hand to partially open the blade rather than a button or lever. Anything with a button on the handle is considered an automatic switchblade and is subject to stricter regulations. The mechanism inside the knife is what makes a spring assisted knife a spring assisted knife and not an automatic knife. Despite the difference in the mechanism, the overall deployment of a spring assist knife is very similar to that of an automatic knife.

Most spring assisted knives have a thumb stud so you can partially open the blade before the spring takes over and springs it into locked position. These knives require you to open the blade out (up to 10%) before the spring engages and fires the blade. Spring assisted knives may also have a flipper on the back of the handle that will flip the blade into place. Carrying a spring assist knife is a great choice if you live in a location that is strict on automatic knives.

There are many different variations on the mechanism that makes a spring assist knife work. But typically they will have a spring or tension bar that is designed to spring open the blade into locked position (see diagram below). What makes them different from an automatic knife is there is resistance after the blade is closed that will keep it closed until the resistance is overcome. Once the resistance is overcome – by manually pushing (ie pushing the blade open with your finger) the blade past the resistance point—the spring engages and does the rest of the work opening the knife for you. Spring assisted knives function much in the same way an automatic knife does. However due the different opening mechanism, a spring assisted knife is not subjected to the same strict laws. If you want to learn more about the spring mechanisms of spring assisted knives I highly recommend our Knife Locking Mechanisms: Spring Assisted Knives post.

Diagram of a spring assisted mechanism for a spring assisted knife. Spring assisted knives can be bought at

The quickest and easiest spring assisted knives to open are ones featuring a flipper. This is an extra piece of steel at the back of the blade that can be used to flip the knife into place. You push the flipper past the point of resistance and the spring takes over and fires the blade into place. There are knives that open with thumb studs (a piece of stainless steel on the bottom side of the knife), the Spyderco Opening Hole (literally a hole that allows your thumb to ‘grip’ the blade to open), and flipper (explained above).  You can easily get these knives to open as fast or faster than an average automatic knife.

If you’re wanting an automatic knife but live in a state where automatics are illegal, I definitely suggest to get a spring assisted knife instead. Spring assisted knives are available at Bladehq as side opening knives or out-the-front knives.

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The Top 7 Spring Assisted Knives by Benchmade


Spring assisted knives are a great choice if you live in an area that has restrictions on fully automatic knives. Because you have to use your finger to activate the blade rather than a firing button, they are not considered full automatics. Some of the best spring assisted knives are made by Benchmade. Benchmade is known for their high quality automatics and folding knives but they also have a few impressive spring assisted models available for sale.

The Best of Benchmade Spring Assisted Knives

Nitrous Stryker Mini-Barrage Torrent Subrosa Barrage 581 Aphid Emissary

Benchmade 913SD2 Nitrous Stryker Spring Assisted Knife (3.7" Satin Serr)

Nitrous Stryker


This first knife on the list is the Benchmade Nitrous Stryker. This unique version of the Stryker knife features the Nitrous Assist mechanism. The spring is actuated by moving the blade out slightly with your hand or the thumb stud. This will forcefully fire the blade into locked position. Benchmade equipped this knife with a modified titanium liner lock frame, G-10 handle scales, thicker liners and thumb studs for easy use. The Nitrous Stryker is a little harder to find than other Benchmades but its unique design and powerful spring action make it a great choice.


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Benchmade Warn 587-1 Mini-Barrage Knife Spring Assist Tanto (Satin PLN)

Warn Mini-Barrage


The Benchmade Warn Mini Barrage is the perfect size for an EDC knife and it comes equipped with a powerful spring assist mechanism. Benchmade teamed up with Warn Industries to create a knife that combines speed and strength into one easy to carry knife. This knife includes a safety switch on the back and a fully reversible clip. Benchmade and Warn products are known for their durability and strength and this is reflected in the Mini Barrage.


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Benchmade 890BK Torrent Spring Assist Knife (Black / PLN)



The Benchmade Torrent is a slim, light knife that makes for the perfect EDC spring assisted knife. This knife is a special design by Ken Steigerwalt that has a streamlined look and amazing spring action. You just have to slightly nudge the thumb stud to activate the Nitrous spring assisted system and lock the blade into place. The torrent comes equipped with G-10 handles, steel liner locks, lanyard hold, and an extended pocket clip for deep pocket carrying. If you’re looking for something small and lightweight that still has a lot of power, the Benchmade Torrent is a great choice.


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Benchmade 790 Subrosa Titanium Knife Spring Assist Monolock (Satin / PLN)



The Benchmade Subrosa is the first titanium monolock that Benchmade has released with a spring assist feature. Like other Benchmade models it is equipped with the Nitrous spring assisted feature that will require the lightest touch to spring the blade into place. The handles are made of machined titanium that makes the knife extremely strong but not too heavy. The knife also has a thumb stud for quick release, S30v stainless steel blade and a steel clip. The Benchmade Subrosa has a unique design that makes it a great choice for collectors and a flawless construction that makes it a good choice for everyday use.


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Benchmade Barrage 581 Knife Spring Assist Axis G10 Handle (3.6" Satin Plain)

Barrage 581


The 581 version of the Benchmade Barrage has some special additions that make it stand apart from other Barrage models. This model features a combo G-10/ Aluminum handle with a new M390 super steel blade. It comes with a safety on the back of the knife, Axis-Lock, spring assist mechanism, ambidextrous thumb studs and a fully reversible pocket clip that makes for easy carrying. The Benchmade Barrage is a beautiful knife that is powerful and comfortable to carry.


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Benchmade Aphid Spring Assisted Knife 340 (2.38" Satin Plain)



The Benchmade Aphid is a small lightweight knife with a powerful spring assist feature. This knife is equipped with the Benchmade Optimiser Assist mechanism. It has a locking liner and a 440C stainless steel blade. The slim Valox handles make the knife very light and easy carry. It also comes with an ambidextrous thumb stud and a reversible pocket clip. This is a great choice for anybody looking for a every day carry knife that can still spring quickly into action when necessary.


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Benchmade 470 Emissary Knife Axis Spring Assist (3" Satin Plain)


One of the best all around spring assisted knives is the Benchmade Emissary. It has a beautiful streamlined design and a compact, smooth firing action. This one of a kind knife comes equipped with a S30V steel blade, reversible tip up pocket clip, safety lock and ambidextrous thumb studs for quick opening. The handle is made of an aluminum alloy that is strong without being to heavy. The Emissary combines all of the best features of spring assisted and EDC knives into one small convenient package.


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No matter which spring assisted knife you choose you will always get the highest quality from Benchmade spring assisted knives. This includes knife design, construction, materials and most importantly functionality. In addition to all of this you will also get Benchmade’s lifetime warranty in case any issues arise with your knife. These things make Benchmade one of the best brands out there for spring assisted or any other type of knife. At Bladehq you can find all the best Benchmade spring assisted knives available.

Which is your favorite Benchmade Spring Assist?

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