The Back Lock mechanism, also known as the Lockback, features a pivoting lock bar or spine located within the knife's handle. When the blade is fully opened, a notch on the blade's tang engages with a hook on the lock bar, securely locking the blade in place. To close the knife, the user presses down on the exposed part of the lock bar at the spine's rear, which disengages the hook from the tang, allowing the blade to fold back into the handle.

The Bolster Lock mechanism integrates the locking system into the knife's bolster, offering a sleek and efficient design. When the blade is opened, a segment of the bolster shifts to secure the blade in place, utilizing the structural part of the knife for the lock. To close the blade, pressure is applied to the movable part of the bolster, disengaging the lock. This design provides a secure lock-up while maintaining the knife's aesthetic and ergonomic integrity.

The Button Lock mechanism features a push-button, typically located on the handle, that controls the locking and unlocking of the blade. When the blade is deployed, the button engages a spring-loaded plunger that fits into a notch on the blade, securely locking it in place. To fold the blade back into the handle, the button is pressed again, releasing the lock and allowing the blade to move freely. This system offers a quick and user-friendly method for operating the knife, providing a secure lock for both opening and closing actions.

The clasp lock operates as a lightweight locking system, utilizing a pin located on the blade's tang. This pin fits into a corresponding lock hole in the rocker arm, also known as the "clasp," securing the blade in its open position. The mechanism functions similarly to a back lock, with the key difference being that the lock is positioned externally on the handle, rather than embedded within it.

The Collar Lock mechanism features a rotating collar around the knife's pivot point, providing a unique and secure locking system. When the blade is opened, the user rotates the collar, which moves into position to block the blade from closing. This action locks the blade securely in the open position. To fold the blade back into the handle, the collar is rotated in the opposite direction, releasing the lock. This intuitive design ensures a robust lock-up with a simple twist, blending functionality with ease of use.

The Compression Lock is a sophisticated locking mechanism developed by Spyderco that utilizes a small, wedge-shaped piece of metal positioned behind the blade. This piece slides into place as the blade fully opens, wedging itself between the stop pin and the tang, effectively locking the blade in the open position. To disengage the lock and fold the blade back into the handle, the user simply presses on the exposed part of the metal piece. This design offers a strong, reliable lock-up, with the added advantage of keeping fingers away from the blade's path when closing, enhancing safety.

The Frame Lock mechanism is an evolution of the liner lock, designed to enhance the knife's structural integrity. In this system, a portion of the knife's handle frame, made from metal, acts as the locking mechanism. When the blade is deployed, this frame piece moves inward and presses against the blade's base, securely locking it in place. To close the knife, the user applies pressure to the frame segment, moving it outward to release the lock, allowing the blade to fold back smoothly into the handle. This design not only ensures a robust lockup but also simplifies the operation, making it highly favored for its durability and ease of use.

The Friction Lock mechanism relies on simple physics, using friction between the blade and the handle to hold the blade in the open or closed position without a traditional locking system. When the knife is opened, the tight fit between the blade's pivot and the handle creates sufficient resistance to prevent accidental closure. To close the knife, the user applies a deliberate force to overcome this resistance. This type of lock is appreciated for its simplicity, durability, and ease of maintenance, making it a favorite in traditional and minimalist knife designs.

The Lever Lock features a distinctive mechanism where a lever, typically flush with the handle when closed, flips up to lock the blade open. This action engages a spring mechanism that securely holds the blade in position, preventing accidental closure during use. The user simply flips the lever down to fold the blade back into the handle, disengaging the lock. This type of lock combines ease of use with a classic aesthetic, offering quick one-handed operation and a secure locking system.

The Liner Lock is a popular locking mechanism in folding knives, characterized by its simplicity and effectiveness. It features a thin, spring-like metal liner within the handle that moves into position behind the blade when it's fully opened. This action locks the blade securely in place. To disengage the lock and close the knife, the user manually pushes the liner to the side, freeing the blade to fold back into the handle. The liner lock is favored for its ease of use, allowing for smooth one-handed operation.

The Slip Joint Lock is a classic knife mechanism that doesn't lock the blade in the open position but instead relies on spring tension to hold it in place. A back spring exerts pressure on the blade's tang, keeping it either fully open or closed. To close the blade, the user simply applies pressure to overcome the spring's resistance. This traditional design is commonly found in pocket knives, offering a simple, reliable means of blade stabilization without a true locking mechanism.

The Tri-Ad Lock, developed by Cold Steel, is renowned for its exceptional strength and durability. It enhances the traditional back lock mechanism by incorporating a stop pin that redistributes force from the blade to the handle, significantly reducing stress on the locking bar. When the blade is opened, the lock snaps into place, securing the blade with unparalleled stability. Disengaging the lock requires pressing down on the release lever at the spine, allowing the blade to fold. This innovative design ensures the knife can withstand extreme pressure and use, making it one of the most reliable locking mechanisms available.