Ball Bearing Lock Secures 2 Pieces Into 1

From left, the ball bearing slides into the channel formed by the blade and the handle as the Spyderco Polliwog is closed. The ball bearing self-adjusts when the knife is opened and/or closed. (David Jung photo)

    

     The idea of a ball bearing used as a knife lock may seem like a contradiction. Ball bearings are designed to keep things in motion, not freeze them in place. However, it is the shape of the ball bearing that gives the Spyderco Ball Bearing Lock some of its greatest strengths.

     Since variations on knife shapes and handle materials are harder to patent, that leaves lock designs. Borrowing such a design involves paying a royalty. Devising your own lock negates paying the royalty but involves many hours of research, design and testing.

     The Ball Bearing Lock began on paper, progressed to plastic models and then to the metal prototype stage. Throughout the process, the lock’s patentability was considered—though holding a patent does not mean the patent holder is free and clear. Competitors love to pore over a design to look for loopholes to exploit. Defending a patented design is crucial to its economic success. In the end, Spyderco CEO Sal Glesser, a Blade Magazine Cutlery Hall-Of-Fame© member, said he felt his Ball Bearing Lock was different enough to warrant a patent, and the design would be difficult to copy.

     The Ball Bearing Lock and the evolutionary caged Ball Bearing Lock comprise Spyderco’s attempt to develop a robust lock that meets martial blade craft (MBC) standards without being too bulky or hard to open or close. The hardened ball bearing, which is the main element, is allowed to rotate freely throughout its travel. Because it will always be in a different position, wear and tear is greatly reduced. Another benefit is the lock continually self-adjusts with each use. Because of its design, it can be operated on either side of the handle. An additional benefit is the lock is hard to accidentally disengage, which adds to its safety.

     One look at the Ball Bearing Lock reveals the creative thought process required in its creation. “The design objective,” Glesser noted, “was to have a fairly simple, very strong, very reliable folding knife lock.”

 

How It Works

When the knife is closed, the ball bearing sits in a slightly curved channel. The channel provides the track for the ball bearing, which is pushed toward the blade due to pressure from a small shaft surrounded by a coil spring. Opposite the slightly curved ramp is the other side of the channel, which is formed by the knife blade.

     As the blade pivots, the ball bearing pushes past the resistance of the closed position detent and follows a circular path until the knife approaches the open position. When the knife is nearly open, the blade channel drops away, allowing the ball bearing to push out into the channel formed at the top of the blade. Throughout the travel, the ball bearing rolls unobstructed with the outward spring pressure, providing the resistance to allow the blade to swing freely. In the open position, the pressure to close is surmounted by the ball bearing locking in place, on top by the liner and below by the blade. When the user removes the outward spring pressure by pulling back on the ball bearing, the blade can be pivoted to the closed position. The hardened ball bearing is unyielding under normal use. In the case of the newer models, a cage of a durable proprietary polymer blend surrounds and centers a smaller ball bearing. The lock action is the same.

 

The Knives

The Ball Bearing Lock debuted in 2002 on Spyderco’s World Trade Center (WTC) Knife, a non-profit fundraiser for victims of 9/11. On the WTC knife and the follow-up D’Allara knife, Spyderco used FRN (fiberglass-reinforced nylon) handles. The FRN made for a fairly thick, though comfortable, knife. Subsequent knives with the Ball Bearing Lock, including the Polliwog, Phoenix and Dodo, used such “flat” handle materials as stainless steel and G-10, which addressed the thickness concerns.

     The first-generation version had a large, hardened ball bearing. Some seemed concerned it took two fingers to easily slide the ball bearing back in its channel. Eric Glesser, Sal’s son, designed the newer version, which addressed the concern by making the ball bearing smaller and enclosing it in the cage that has more grip and a much thinner profile.

     The original Ball Bearing Lock was visibly different than any other lock, and some of the first models using it did not look traditional. Eric’s Polliwog design allows the ball-bearing channel to be open when the knife is closed, making it appear the ball bearing could slip out. Eric’s Dodo design features an ergonomic handle. It is scheduled to return in Spyderco’s carbon fiber and orange G-10 “Sprint Run” versions. The Phoenix, designed by knifemaker Howard Viele, also used the larger Ball Bearing Lock.

     The P’Kal has the caged Ball Bearing Lock, The knife is based on an edged martial arts technique from the Philippines, which involves an “ice-pick” grip with corresponding downward pulling thrusts. Lock strength is crucial in knives used in the martial arts, so the P’Kal needs the MBC-rated lock.

     The knife that has received the most attention of the caged series is the Manix 2. The original Manix knives featured a massive, heavy-duty design. By moving to the caged version of the Ball Bearing Lock, Spyderco changed the Manix in a positive way for everyday carry.

 

Use & Maintenance

The Ball Bearing Lock takes some getting used to if you are accustomed to LinerLocks™ or traditional lockbacks. Opening is the same as with other Spyderco knives via the blade hole. The difference is in closing. While it is possible to unlock the blade using one side of the lock, the best way is to pull the lock cage back with the thumb and index finger until it releases. Once the lock disengages, the blade can be pivoted closed. “People either like it or they don’t,” Sal observed. “They like the smooth action. They like the strong lock-up. We wanted it functional and easy to open, but I guess ‘not too easy’ would be one way of saying it.”

     Among the advantages of having an exposed lock is ease of cleaning. “We usually just rinse them out and add a drop of oil here and there,” Sal said. “We’ve never had an issue with the spring. These coil springs go a long time, so really there is not much maintenance, other than occasional oil.”

     The Ball Bearing Lock is one of many locks on the market. Others that share similar characteristics include the Bolt Action Lock designed by Cutlery Hall-Of-Famer Blackie Collins, and the Axis lock designed by Bill McHenry and Jason Williams and found on several Benchmade folders.

     “I think all locks compete and have advantages and disadvantages, so I don’t know that one would be better than another,” Sal opined. “Most locks will either slide or rotate; I guess [the Ball Bearing Lock] would be considered sliding, although it is more rolling than sliding that is the action of the lock.”

     Hence, the Ball Bearing Lock takes the contradictory rolling motion of a ball bearing and the sliding of a piston into a channel to lock two pieces of metal into one. It is a contradiction that works.—by David Jung

 

For more information on the Ball Bearing Lock and the Spyderco knives that have it, contact Spyderco, attn: J. Laituri, 820 Spyderco Way, Golden, CO 80403 800.525.7770 www.spyderco.com, customerservice@spyderco.com.

 

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