Benchmade 3551 Stimulus Auto Knife — New Product Announcement

Based in Oregon, the epicenter of U.S. knife production, Oregon City’s Benchmade ranked second when Knife News conducted a brand-awareness survey of blade enthusiasts in 2015. Formulated and refined over Benchmade’s 30-year history, the company’s strategy applies state-of-the-art manufacturing and production processes to custom knife designs from industry-leading knife makers, making high-quality implements available to a larger customer base than previously could obtain them and at price points that reflect higher-scale production. Benchmade also elevates the standards applied to everyday carry knives, transforming production hardware into gear that meets the standards often applied to custom equipment.

 

Benchmade founder Les de Asis’ knife-making history began in 1979 when he embarked on an effort to improve upon the butterfly knives he had used in his youth. After some setbacks, he applied the Benchmade name to the second of his cutlery companies, reflecting the combination of handmade quality with precision-fabricated materials. Relocated from California to Oregon to take advantage of the acceptance of styles of knives that face legal restrictions in other jurisdictions, the company pioneered the use of laser cutters to work with steels that were too hard to produce with stamping equipment. Benchmade earned, and still holds, a world-leading position in the manufacture of automatic knives.

 

Among its products, Benchmade offers three separate hand-assembled knife series, each made in the U.S. and crafted to match the expectations of a differing group of users. Benchmade’s Blue Class targets the recreational knife enthusiast who needs a blade for tasks that qualify as light duty. Benchmade’s Gold Class consists of custom-made, limited-edition creations. The Black Class aims at professionals, including those who work in law enforcement, public safety, and the military. In establishing its product lineups, Benchmade has partnered with numerous master designers, including Mel Pardue of Repton, Alabama, the senior-most custom craftsman associated with Benchmade, with a 40-year career filled with outstanding knives. Pardue’s offerings through Benchmade highlight clean lines and upscale simplicity, along with a diligent focus on hard-working utility.

 

Within the Benchmade Black Class, the 3551 Stimulus is a Mel Pardue design that represents a refinement of the popular 3550 automatic knife that preceded it. With a new name and an enhanced feature set, the Benchmade 3551 Stimulus continues to constitute an everyday knife with tactical capabilities—or a tactical knife suitable for use as an everyday carry. The Benchmade 3551 Stimulus features the lifetime LifeSharp warranty coverage that accompanies all Benchmade products. Under this program, an owner can ship a Benchmade knife back to the company for a complete reconditioning process, provided at no charge by a technician team dedicated to this service. Each knife undergoes complete disassembly, after which a technician replaces or tunes up any parts that show signs of wear. Lubricated and reassembled, the knife receives a factory sharpening prior to shipment back to the customer.

 

 

Blade Profiles and Finishes

 

The Benchmade 3551 Stimulus continues the Benchmade 3550’s spear-point blade design. Spear-point blades offer a symmetrical profile that narrows to a tip positioned at the midpoint of the blade height. They combine much of the strength of a drop-point blade with some of the piercing ability of a dagger-like needle-point profile. A spear-point blade may not offer the expanding cutting surface of a blade with a large curved belly, but spear-points serve a specific need and purpose for users who want to combine cutting and piercing capabilities in a single knife.

 

Like the 3550, the 3551 comes in models with plain edges or with one partially serrated edge, and in satin or coated black finishes. It favors the right-handed user in the placement of its automatic controls.

 

Blade Steel

 

Benchmade’s 3551 Stimulus uses Crucible Industries’ U.S.-manufactured 154 CM stainless steel. Currently based outside Syracuse, New York, Crucible Industries traces its history back to late 19th-century England and forward to a merger among 13 crucible-steel companies at the turn of the 20th century. This merger produced a steel giant known as the Crucible Steel Company of America.

 

Crucible began creating steel for knife makers early in the 21st century. By this time, the company had invested many innovative decades in the creation of alloys for use in the manufacture of tools and automobiles. Crucible also excelled in the production of more-exotic materials, such as a titanium alloy for use in Robert Jarvik’s implantable artificial heart design. As the years progressed, the company’s fortunes reflected the ups and downs of the industries it served and the world economy as a whole, culminating in the emergence of what had been the Crucible Specialty Metals Division as Crucible Industries in 2009.

 

Crucible’s 154 CM formula adds a mixture of carbon, chromium, manganese, molybdenum, and silicon to the iron that forms the basis of stainless steel. At 1.05 percent carbon, 154 CM qualifies as a high-carbon steel. The inclusion of carbon in a steel alloy raises the hardness and increases the wear resistance of the resulting metal at the potential expense of reduced toughness. At 14 percent chromium, 154 CM exceeds the minimum of 12 percent to 13 percent that qualifies an alloy as a stainless steel. Thanks to chromium’s ability to raise a blade’s corrosion resistance, stainless steels have become mainstays of knife production. Chromium also heightens tensile strength and hardness. Additionally, the 0.50 percent manganese in 154 CM fosters hardness, tensile strength, and wear resistance. With 4 percent molybdenum, 154 CM gains high-temperature strength and demonstrates improved edge retention. The addition of 0.30 percent silicon also helps increase hardness and ward off pitting.

 

Crucible’s 154 CM consists of a variation on the high-carbon martensitic stainless steel alloy called 440C. The terms “martensite” and “martensitic” reference a very hard crystalline structure in a steel produced by a diffusionless transformation, or phase change, that occurs when the molten alloy quenches rapidly enough to produce a metal that is supersaturated with carbon. The production of martensitic steel begins with austenization, a high-heat process that changes the crystalline structure of the alloy. The quenching techniques that produce martensitic steel follow this heating process. The corrosion resistance, wear resistance, and hardness of 154 CM exceed the equivalent properties of 440C, an alloy often used in knife blades because of its high level of corrosion resistance.

 

At 58-61 RC on the Rockwell HRC scale, a measure of hardness, the 154 CM stainless steel alloy in the Benchmade 3551 Stimulus blade offers the toughness and edge retention that combine to make a knife reliable in two respects: Resistance to chipping and other forms of damage that can plague overly hard blades, and the ability to hold a sharp edge well. The tougher the steel alloy, the more difficult it can be to sharpen, but the payoff comes in the durability of that edge sharpness. The Rockwell C measurement scale determines material hardness through a laboratory test that involves indenting the steel with a test instrument and measuring how far the instrument penetrates the surface of the metal.

 

The combination of noteworthy hardness and edge retention with good toughness have made Crucible’s 154 CM a popular choice in knife production, as well as in the manufacture of valve ports, bearings, and bushings. Along with the chemical composition of this alloy, the nature of the heat treatment applied during production makes or breaks its attributes and determines its suitability as a knife-making material.

 

To protect knives made out of 154 CM from the corrosion that can accrue on this alloy, keep your Benchmade 3551 Stimulus dry and away from humidity. Particularly in humid climates, periodically apply a light coat of oil to keep oxygen away from blade metal.

 

Handle Material

 

The Benchmade 3551 Stimulus features a black anodized 6061-T6 billet aluminum handle similar to the handle on the Benchmade 3550. 6061-T6 constitutes a heat-treatable wrought aluminum alloy that incorporates magnesium and silicon. It excels in applications that require both strength and toughness, additionally exhibiting high degrees of corrosion resistance in atmospheric conditions and in salt water. The suffix “T6” in the alloy designation shows that it was solution heat-treated and artificially aged.

 

In its pure form, aluminum displays too much softness to make it a viable choice for parts such as knife handles that see use in a wide range of ruggedly demanding scenarios. As an alloy, however, 6061-T6 offers the durability produced by the addition of other elements in a metal with a high strength-to-weight ratio that makes it ideal for use in aircraft and boat construction, heat exchangers, piping, tubing, and bicycle frames, as well as knife handles.

 

Perhaps the most famous application of 6061-T6’s lightweight strength came when NASA chose it as the material from which to craft the gold-anodized plaques for spacecraft that explored Jupiter, Saturn, and Venus beginning in the early 1970s. Launched in 1972 and 1973 respectively, Pioneer 10 and Pioneer 11 included plaques fabricated from 6061-T6, and engraved with pictorial representations of human figures, a diagram of the solar system, a drawing representing the Sun’s position relative to the center of its galaxy and 14 stars, and a chemical schematic, all drawn by Linda Salzman Sagan, then the wife of the late astronomer and astrophysicist Carl Sagan. In the event that the Pioneer spacecraft reached any destination that included intelligent life, the plaques were meant to serve as a pictographic introduction to the Earth, its location, and its dominant species. NASA used 6061-T6 aluminum in a far more exotic application than a knife handle, providing a testament to the lightness and durability that also make this alloy an attractive choice in more mainstream production situations.

 

As a billet aluminum part, the handle for the Benchmade 3551 Stimulus takes its shape not through a casting process but by machining the parts out of a bar of aluminum alloy. Billets are cast or extruded into flat and cylindrical shapes. Creating the handle from billet aluminum produces highly precise fabrication, smooth surfaces finishes, and greater structural strength than a cast part could offer. Benchmade uses CNC machining equipment and advanced manufacturing techniques to produce handles that display absolute adherence to specifications, beyond the fidelity that cast parts could accomplish. The Benchmade 3551 Stimulus also includes a lanyard hole positioned at the end of the handle.

 

The anodized black finish on the Benchmade 3551 Stimulus handle comes from an electrochemical process that adds a protective coating of aluminum oxide to the 6061-T6 aluminum alloy. This finish contributes to corrosion resistance and abrasion resistance. To apply an anodized finish, aluminum parts are immersed in an acid electrolyte bath through which an electric current passes. Oxygen ions from the chemical solution combine with the aluminum atoms on the surface of each part. Aluminum oxide runs thicker than aluminum itself, so the anodizing process actually adds fractionally to the dimensions of the part. The durably hard coating it produces neither peels off nor wears out. Because of its strength, the coating is applied only after a part is machined, reducing the amount of effort required for tooling and the potential wear and tear on production equipment. Ironically, this desirable finish actually constitutes a controlled form of naturally occurring oxidation, the chemical process that underlies the corrosion that all knife owners try to keep from encroaching on their blades.

 

Knife Dimensions and Weight

 

Like the 3550, the Benchmade 3551 Stimulus packs big performance into a small (and now a little bit lighter) package. Its lightweight handle and flat blade profile put a versatile tool in your hand without any excess weight or volume.

 

Slightly thinner and lighter than its longtime predecessor, the Benchmade 3550, the Benchmade 3551 Stimulus measures nearly the same dimensions as the 3550. Overall length stays unchanged at 7.1 inches, as does closed length at 4.1 inches. Blade length on the 3551 Stimulus runs one one-hundredth of an inch longer at 2.99 inches, and blade thickness runs two one-hundredths of an inch thinner at 0.088 inches. Handle thickness also decreases by one one-hundredth of an inch on the Benchmade 3551 Stimulus to 0.46 inches. Subtle changes in design dimensions put the 3551 Stimulus at 2.71 ounces, down from 2.8 ounces on the 3550.

 

Updated Push-Button Automatic Package

 

The Benchmade 3551 Stimulus combines a slim shape with a flat profile and a responsive automatic blade action. Benchmade has updated the push-button automatic blade action on the 3551 Stimulus to offer greater reliability than the version found on its predecessor, the 3550. The new design enlarges the side-mounted pushbutton, making it easier to operate. The spine-mounted sliding plunge lock safety mechanism combines quick, smooth functionality with the security you expect on an automatic knife.

 

Reversible Pocket Clip

 

Mounted with a trio of Torx-head screws, the reversible, removable pocket clip on the Benchmade 3551 Stimulus accommodates tip-up or tip-down use.

 

The Long and Short of It

 

The Benchmade 3551 Stimulus evolves and refines the design and materials used in the company’s popular 3550 automatic knife. It may not appeal to the general-purpose knife user, but for the professional who needs its specific strengths, it can combine everyday carry adaptability with tactical functionality in a sleek, compact, lightweight package.

 

	3550	3551
Weight	2.80 oz.	2.71 oz.
Overall length	7.10″	7.10″
Closed length	4.10″	4.10″
Blade length	2.98″	2.99″
Blade thickness	0.09″	0.088″
Handle length	4.10″	4.10″
Handle thickness	0.47″	0.46″
Handle material	Anodized 6061-T6 billet aluminum	Anodized 6061-T6 billet aluminum
Handle color	Black	Black
Blade material	154 CM stainless steel	155 CM stainless steel
Blade hardness	58-60 RC	58-61 RC
Blade style	Spear-point	Spear-point
Blade grind	Flat	Flat
Blade finish	Satin (3550 and 3550S) or Black (3550BK and 3550SBK)	Satin (3551 and 3551S) or Black (3551BK and 3551SBK)
Blade edge type	Plain (3550 and 3550BK) or serrated (3550S and 3550SBK)	Plain (3551 and 3551BK) or serrated (3551S and 3551SBK)
Pocket clip	Black, removable, tip-down	Black, removable, reversible, tip-up or tip-down
Lock mechanism	Auto open with safety	Auto open with safety
Opener	Push button automatic	Push button automatic with larger button
Lock type	Plunge lock	Plunge lock
Sheath material	Sheath sold separately	Sheath sold separately
Benchmade product class	Black Class	Black Class
User	Right handed	Right handed
Best use	Tactical	Tactical
Manufacturer’s suggested retail price	$200	$210

 

Interested in owning your own Benchmade Stimulus knife?  Check out our product page here and pick up one for your collection.