Buck Rush Knife Dismantled Assisted Opening Knives Information

Assisted opening knives are often confused with automatic knives. Automatic knives have spring loaded blades which open at the press of a button and these are illegal in the UK. The blade of an assisted opening knife does not open at the press of a button. The blade is held closed until it has been manually opened past the thirty degree position. Once the blade has been partially opened, it then engages a spring to rapidly open the blade.

Several manufacturers have developed their own assisted opening technology. These include the Benchmade 'Optimiser' and Kershaw 'Speed Safe' designs. In the case of the Buck Rush Knife, the force which fully opens the blade is provided by a pair of coiled springs, built into each aluminium handle slab. These act to open the blade fully once it has been manually opened past 30 degrees.

The action of the springs is controlled by an eccentric cam pivot in the blade tang behind the pivot pin. In the closed position, the direction of the force is such that it keeps the blade closed. As the blade is manually opened past the 30 degree position, the force of the springs gradually increases to rotate the blade open. The speed of opening may be adjusted by tightening or loosening slightly the pivot pin retaining screw (a size T7 Torx fixing).

Handy Niknaks

The Rush is one of Buck's knives which features their patented 'ASAP' assisted opening technology. As the blade is not activated by a button and has to be partly opened by manual force, this is not an automatic knife. The blade has a safety lock to prevent accidental closure. This is in the form of a liner lock, consisting of a tensioned phlange of the steel handle liner, which engages with the offset ground blade heel.

The knife may either be opened using one of the ambidexterous thumb studs or by pressing the flipper extension on the front of the blade tang. In addition to the liner lock there is an opening safety lock which prevents accidental opening of the blade. This is an oval shaped steel sprocket which locks into the concavity in front of the blade flipper extension, and prevents the blade from rotating forwards.