Spring Assisted Knives – a Practical Guide


Spring assisted knives (also known as assisted-opening knives) are knives that use internal mechanisms to complete the opening process of the knife after it has been started by using a thumbstud attached to the blade or flipper.

The blade on spring assisted knives are held in place by torsion springs when in the closed position, or sometimes additional blade locks on some models. The person operating the knife applies pressure to the thumbstud to start opening the knife, the mechanism then rapidly rotates the blade into a fully open position. This is done by the internal torsion spring moving along a track liner inside the handle.

Spring assisted knives are often confused with switchblade knives. Switchblades are opened automatically by pushing a button on the handle. With spring assisted knives however, the person operating the knife needs to open it about one-quarter of the way before the mechanism takes over.

The classification between spring assisted knives and switchblades needs to be clear, there are legal restrictions on carrying switchblades across many US states and countries. While the legal restrictions on spring assisted knives are a lot more relaxed.

Many knife manufacturers have trademarked their own terminology for the mechanism they use on their spring assisted knives, although the principles of how they work are very similar.

How Much Do Spring Assisted Knives Cost?

There is no straight answer for this as they can range from a few dollars all the way up to thousands of dollars. Generally speaking the price will be relevant to the quality of the knife though, so if you have a budget you should look for knives around that range and read our reviews on this site.

The mechanism itself used in spring assisted knives is not expensive to implement on a basic level. It is advisable to look past the cheaper versions however, as it is unlikely they will come with warranties and are prone to failing after many repetitions.

US made models from companies like Kershaw, Buck and Benchmade are made through a high quality process, come with limited lifetime warranties and have a reputation for longevity.

Three examples of highly rated spring assisted knives are as follows:

Kershaw Cryo Knife assisted opening

Kershaw Cryo Assisted Opening Knife

The Kershaw Cryo is a great example of a good quality spring assisted knife made by a respected manufacturer. It is an affordable, small, functional pocket knife aimed at EDC use. Ideal as a first time knife or part of a larger collection, there is a wide range of uses for the Cryo.

Here is a quick summary of the pros:

  • Small, compact EDC pocket knife
  • Smooth look and color matched handle and blade
  • Very competitively priced, hard to find a cheaper knife of this quality
  • Has a Hinderer lockbar stabilizer to prevent over extension
  • Assisted safe flipper opening makes it quick and easy to deploy the blade
  • Carrying the Kershaw name you are assured of quality
  • Frame lock locking system

Full review and specs coming soon, for now view it on Amazon.

SOG Flash II with S A T assisted opening knife

SOG Flash II with S.A.T.

SOG have their own spring assisted system called SOG Assisted Technology (S.A.T.). It incorporates opposing high-tension coil springs that trigger when the opening action is kicked off by the user.

With the Flash II model you are getting a partially serrated 3.5” blade crafted out of AUS-8 stainless steel, and a fiberglass-reinforced nylon handle. It’s an excellent all round knife with a lot of positive feedback from users.

Here is a quick summary of the pros:

  • Incredibly light for its size
  • Super quick to deploy the blade
  • Sharp and ready to go out of the box
  • Easy to sharpen at home steel
  • Built to SOG’s excellent high standard
  • Pocket clip enables deep pocket concealment
  • Great value for money
  • An awesome all-rounder

Full review and specs coming soon, for now view it on Amazon.

Benchmade 585 Mini-Barrage Osborne assisted opening knife

Benchmade Mini-Barrage 585 with Assisted Opening

The Benchmade Mini-Barrage 585 is smaller than your average EDC pocket knife, hence the ‘mini’ part of the name. The Benchmade assisted opening mechanism is incredibly smooth and quick, deploying the blade at a seconds notice is not a problem.

It currently has a 5 out of 5 rating on Amazon from user feedback, I strongly recommend you read the full review or take a look at availability.

Here is a quick summary of the pros:

  • Lightweight and compact
  • Blade deploys quickly
  • Sharp and ready to go out of the box
  • Easy to sharpen at home steel
  • Built to Benchmade’s excellent high standard
  • Well balanced to sit comfortably in hand
  • Great all round EDC knife

Click here to see the full review and specs.