If you carry a folding knife for personal defense, one skill you absolutely need to develop is the ability to open it quickly and reliably under stress using only one hand. Without that skill, your knife won’t be available when you need it most. Opening your folding knife with one hand is possible with various methods, but for this episode of Street Smarts, we will focus on inertial opening.
Using Inertial Energy to Open Your Folding Knife
Most modern tactical folding knives include some kind of feature that allows them to be manually opened with one hand. Typically, these include studs, holes, or disks that provide a purchase for thumb opening, or flipper tab for index-finger opening. While they certainly work, they also require you to hold the knife in a specific way before initiating the opening. Likewise, they rely on fine motor skills that disappear under stress.
With an inertial opening, you never touch the blade. Instead, the closed knife is rapidly rotated around the blade’s pivot pin. When your hand and the knife stop, the inertia imparted to the blade allows it to continue its movement, overcoming the detent force that keeps it closed and rotating it into the open, locked position.
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To perform a standard-grip inertial opening, grip the closed knife between your fingertips and thumb with your fingers extended and perpendicular to the knife’s handle. Holding the knife in front of you and your elbow slightly bent, raise your elbow slightly above horizontal, then lower it quickly until it touches your ribs.
As you do this, make sure the knife’s pivot pin stays in the same place in space. The blade will always rotate around the pivot pin, so everything else must rotate around that point.
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Performed explosively, this movement will transfer inertia to the blade and open it quickly and positively. Like any other skill, however, it takes practice. It’s also easiest to learn by starting with heavy-bladed folders with light lock detents and building your skills from there.
