Opening Systems

Most Zero Tolerance knives offer fast and easy one-handed opening, either with our KVT ball-bearing system or assisted opening. However, some ZT have different systems, as well as a variety of ways to access them. Learn more about our current opening systems below. For more about ZT locking systems and how to use them, see Lock Types.

Opening Action

The opening action is determined by the internal mechanisms around the folder's pivot. ZT pocketknives provide smooth opening action using a variety of opening mechanisms.

Manual with KVT Ball Bearings 

Relies on a ring of “caged” ball bearings that surround the knife’s pivot and enable the blade to move out of the handle smoothly. KVT makes opening manual knives as smooth, easy, and often as fast as assisted opening.

Manual with Washers

No springs, torsion bars, or caged ball-bearings, these folders rely on washers for a simple pivot open with a thumb stud, thumb disk, flipper, or nail nick in the blade.

Assisted Opening

ZT assisted opening relies on a torsion bar to help you smoothly open the knife with a manual push on the thumb stud or pull back on the flipper. When closed, the torsion bar in the handle creates a bias toward the closed position. When opening, the torsion bar adds to the pressure from your finger, and pushes the blade open.

How to Open a Zero Tolerance Folding Knife

There are different ways to open your pocketknife, depending on its external mechanism. Here's how to open ZT folders with our most common mechanisms.

Flipper

The flipper is a metal extension found at the back of the blade near the pivot. It can be found on both assisted and manual folders.

Opening with a Flipper, Assisted:

1. Hold the knife handle vertically in one hand.
2. Place your index finger on the top of the flipper.
3. Gently apply downward pressure on the flipper.
4. SpeedSafe opens the knife quickly and easily, and the blade locks into place.

Opening with a Flipper, Manual:

1. Hold the knife handle in one hand with the butt end resting firmly in the palm of your hand.
2. Place your index finger on the highest point of the flipper.
3. Push down strongly and quickly on the flipper.
4. The blade will move out of the handle and lock into place. If you have trouble moving the blade fully out of the handle, add a slight flip of the wrist.

Nail Nick

The nail nick is a groove in the top of the blade, usually halfway down the length of the blade. It is found on manual folders.

Opening with a Nail Nick:

1. Hold the knife handle in one hand.
2. With your other hand, hold the blade at the nail nick.
3. Slowly open the knife, following the path of the blade until the blade is fully open.
4. The blade on most manual folders will lock into position. A slipjoint model will not have a locking mechanism.

Thumb Stud

The thumb stud is a small stud at the top of the blade near the pivot. It may be on one or both sides of the blade.

Opening with a Thumb Stud, Assisted:

1. Hold the knife handle vertically in one hand.
2. Place your thumb on the thumb stud.
3. Gently push outwards on the thumb stud.
4. The SpeedSafe assisted opening mechanism opens the knife quickly and easily, and the blade locks into place.

Opening with a Thumb Stud, Manual:

1. Hold knife handle in one hand.
2. Place thumb on the thumb stud.
3. Push outward on the thumb stud.
4. Continue pushing and follow as you rotate the blade out of the handle and lock it into place.

Thumb Disk

The thumb disk is a small disk found at the top of the blade.

Opening with a Thumb Disk, Manual:

1. Hold knife handle in one hand.
2. Place thumb on the thumb disk.
3. Push outward on the thumb disk.
4. Continue pushing and follow as you rotate the blade out of the handle and lock it into place.

Emerson Wave Shaped Feature®

This is a wave-shaped hook built into the back end of the blade, similar to the flipper.

Opening with an EWSF, Manual:

1. Make sure closed knife is snugged up against the rear seam of your pants pocket, tip-up, as shown.
2. Reach into the pocket to hold the handle of the knife, keeping your fingers away from the blade.
3. Pulling toward the rear seam, withdraw the knife from your pocket quickly and steadily so that the Emerson Wave Shaped Feature hooks on the rear seam of the pocket.
4. This will automatically open the blade. By the time it’s fully out of the pocket, the knife will be open and ready for use. Pull back quickly and smoothly to ensure blade lock up.

SLT (Spring-Loaded Tab)

The SLT is a small folding tab found at the base of the blade near the pivot. It provides all the function of a flipper, but without a visible flipper to interrupt the visual lines of the knife.

Opening with SLT:

1. Hold the knife in one hand.
2. The SLT flipper is concealed, held in place with a spring.
3. Pull back on the concealed tab to overcome the spring’s resistance.
4. Continue pulling back to fully open the knife.