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EDC Press Room

February 2000

Space Age Technology Leads

The Kershaw "Black Out" Into The Next Millenium

BY KATE McPHERRON-Knives Illustrated

Kershaw's new Black Out folder is more like a hand-crafted knife than a factory model, blending expert design with state-of-the-art craftsmanship and production technologies—truly a knife for the new millennium. Here's the story behind how Kershaw's most successful knife and winner of Blade Magazine's 1999 Best Buy award, came to be.

In 1998, Kershaw Knives invited top knife designer Ken Onion to design a signature knife that would bring Onion's "custom" feel to a mass-produced, lower cost knife. To assure a truly unique product, Kershaw embarked on its first U.S. injection-molded handle. They brought in plastics injection molder PolyCast Inc., of Tigard, Oregon, to incorporate the state-of-the-art design and materials that would assure the power and subtlety of Onion's design would carry through the production process. As a result, the Black Out incorporates a wide range of sophisticated technology never before used in knife production.

"We drew on our experience in the automotive and aerospace industries to build this knife, looking at parts like nylon truck hub control dials that engage four-wheel drive and put up with wear and heat stress," says Rick Thomas, business development manager for PolyCast. "But we knew a utility knife would be subjected to harsh conditions that would never occur in an automotive setting."

PolyCast worked with Portland, Oregon based Engineering Design Consultants, Ltd. (EDC) to design the knife handle, knowing that they could rely on EDC's experience designing aerospace and heavy truck parts to help with material selection and appearance and to design function based on empirical testing. In fact, the Black Out uses the same design, testing and production methods used in parts for high performance cars, military jets and even the space shuttle.

Kershaw supplied a box of knives and a two-dimensional prototype sketch. In about a week, using the highly sophisticated CATIA computer-aided design (CAD) system and a process familiar to aerospace engineers, EDC created a three-dimensional model of the handle. Then, using a rapid protoyping (LOM) machine, they automatically created a solid three-dimensional prototype from the computer-based model. Ken Onion took the prototype and made it his own, sanding off ends and carving refinements. EDC then took Onion's customized prototype and scanned it, taking thousands of cross-sections from the physical shape to create a new 3-D CAD model. The handle's two parts include a checkering texture like a gun grip on the outside and attachment points on the inside for brass inserts, hidden fasteners that keep the outside appearance clean with only two fasteners at the ends and a third mid-way, visible from only one side.

From the outer shape, EDC worked to fit the blade, liners and Speed-Safe opening mechanism inside, while keeping in mind strength and ease of molding. Again, using aerospace technology, they field tested the handle designs with FEA (finite element analysis), checking the handle's rigidity under simulated load and looking for failures, all using a computer.

Kershaw wanted the whole package to be less than one half of an inch and have a contoured handle, which posed a challenge to EDC because the blade and liners are close to one half of an inch themselves. "We had limits as far as aesthetics in this small physical envelope," said Rodger Garner, CEO of EDC. "Luckily, handles are usually over-designed, so just like in aircraft parts, we took weight out by trimming the liners and using a rib design."

"We spent a lot of time with EDC to design this knife to make our job, the molding process, easy," said Thomas. "Most designers who create an asymmetrical shape have varying wall thicknesses in the part that can cause a lot of challenges for us in the injection molding. EDC designed around these challenges, creating a flat part with low molded-in stress that molds perfectly, reduces manufacturing time and is very strong and cost-effective."

"The ribs strengthen the part, but also allowed us to incorporate fastening techniques on the inside that keep the outside of the knife free of fasteners," Garner added. For instance, the handle mold includes a sunken 1/4 inch hex shape on one side of the pivot that holds the bolt head and allows one-handed tightening.

Like many truck and airplane parts, the material used in the Black Out handle is nylon, offering weatherability and touch impact strength. PolyCast chose a 30% glass-filled Bylon 6 because glass fill gives the handles stiffness and structural integrity, while Nylon 6 offers the best cosmetic qualities, disguising the glass in its matte finish.

The final design results in a knife that not only optimizes handle material and the injection molding process, but also makes the best possible use of parts once assembled. The way the liners are screwed into the tow halves of the handle reinforces it and makes the knife extremely rigid, yet as light as possible. And molded-in features, like the recessed pivot-screw head that allows on-wrench adjusting, help simplify production.

The Kershaw Black Out knife pushes a lot of parameters, from the very rapid 11 week concept-to-production turn-around time to the intergration of craftsmanship and high technology into a mass-produced knife.

"What I put into products with craft and care, these guys were able to amplify with precision and technology," said Ken Onion, reflecting on the fascinating process of working with EDC and PolyCast.

The Kershaw Black Out is one of Ken Onion's latest designs being marketed by Kershaw Knives. In addition to featuring a state-of-the-art handle, it sports a partially serrated 440A stainless blade. Weighing only four ounces, you won't even feel the weight if its pocketed. A pocket clip is also a part of this knife, which features a Speed Safe action.

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