Knife Handle Materials: Understanding Your Options

While the blade is unquestionably the soul of a knife, the design and construction of its handle are every bit as important in defining its function as a cutting tool. Historically, the materials used to craft knife handles have had a profound effect on their durability, user friendliness, and visual appeal. Exotic and highly sophisticated materials can further elevate a knife’s aesthetics, uniqueness, and value. Well-educated knife enthusiasts therefore owe it to themselves to understand the intricacies of knife handle materials and the myriad options currently available.

During our 50-year history, Spyderco has explored a wide variety of handle materials in the production of our knives. That experience has given us some hard-won wisdom when it comes to choosing materials best-suited for specific knife designs and applications. In addition to cost, we also have to consider factors such as machinability, strength, dimensional stability, vulnerability to chipping and cracking, water and chemical resistance, resistance to color fading and wear, consistency, and long-term availability. With all those complex factors in mind, here’s a brief overview of some of our most popular handle materials and the advantages and disadvantages of each.

Botanists estimate there are more than 60,000 different species of trees on Earth. No doubt the “original” knife handle material, the wood from those trees comes in a dizzying variety of colors, hardnesses, and grain patterns. Because its quality and appearance are determined by nature, as a manufacturing material, wood is also an inherently inconsistent material. While one piece may have a beautiful, complex grain pattern, another may be very plain. Depending upon its rarity, the availability and price of a particular type of wood for large-scale production can also vary significantly, especially over time.

The greatest challenge with wood, however, is its dimensional stability. Changes in temperature and humidity can cause it to shrink, swell, and warp—especially when it is cut into thin pieces to make knife handles and scales. Although stabilizing the wood—drying it in a kiln and then impregnating it with an acrylic resin in a vacuum chamber—can greatly improve wood’s long-term stability, it’s no guarantee.

Animal bone is another very traditional material that has historically been used for knife handles. The dense leg bones of animals such as cattle, camels, and giraffes are among the most prized sources of bone. This material is typically cut to form scales and may be either polished or “jigged” (carved with a textured pattern) to improve its grip. To enhance their appearance, bone scales are often dyed to achieve attractive colors. 

Like wood, bone is handsome, very traditional, and adds tremendous character to a knife. Since it is a natural material, it is often impregnated with resin and vacuum-treated to maximize its dimensional stability.

One way to mitigate the dimensional unpredictability of wood is to laminate it. By slicing hardwood—usually birch—into thin layers and gluing those layers together, the result is a material that is much more stable than a solid, homogenous piece of wood. The layers are typically soaked in a phenolic resin and compressed under high pressure while the resin cures. This not only bonds them together permanently but also seals their grain more effectively than ordinary stabilized wood. Additionally, this treatment allows the material to take an exceptionally high polish. When contoured, this laminated wood reveals its layered construction, so its layers are often stained different colors before laminating to create a contrasting color theme.

G-10, or G10, is a high-pressure fiberglass laminate created by stacking multiple glass cloth layers, soaking them in epoxy resin, and applying pressure and heat to cure them. Originally developed as a substrate for printed circuit boards, its designation, G-10, comes from the National Electrical Manufacturers Association (NEMA) NEMA LI-1 “Industrial Laminated Thermosetting Products” standard. This standard was revised in 1999 to mirror and ultimately replace a similar military specification for laminated materials, MIL-I-24768. Based on these standards, the formal description of G-10 is “a fully cured, stock shape, form of composite material from continuous filament fiberglass cloth (plain weave, e-glass) with a non-brominated (not flame retardant) epoxy resin system.”

G-10 is extremely strong, dimensionally stable, and offers high levels of electrical insulation and chemical resistance. It also does not tend to absorb moisture, especially when polished. Although originally available in a limited number of colors, today G-10 is produced in a full spectrum of color choices. In addition to solid hues, it is also available in layered, multi-color formats. Conventional G-10 can be readily machined to yield complex shapes and textures and can also be bead blasted, sanded smooth, or polished. It is also available in a “peel ply” form that includes a pre-textured top layer. Once the scale is machined to shape, this layer is peeled off to reveal a non-slip checkered texture.

Micarta is a trademarked brand name for composites made with linen, canvas, paper, or other fabric impregnated with phenolic resin. Developed by George Westinghouse at least as early as 1910, it originally used phenolic resins invented by Leo Baekeland, “The Father of the Plastics Industry” and inventor of Bakelite. These resins were used to impregnate paper and various fabrics, which were then cured under high pressure and temperature to produce laminates. Micarta was widely used in industrial applications such as electrical insulators and printed circuit board substrates. It was first used for knife handles on handmade World War II “Theater” knives and on Randall knives as early as 1959. Later, legendary knifemaker Robert W. Loveless popularized it by using it on his iconic custom knives.

Although not as structurally strong as G-10, Micarta is durable and very dimensionally stable. It can be sanded, bead blasted, or polished to achieve different finishes and textures and develops a handsome patina with age and use. Polishing makes it more water resistant and highlights the distinctive character of its layered construction, especially when it is made with coarse-textured fabrics like canvas and burlap.

Carbon fiber, also known as graphite fiber, is lightweight material that is five-times stronger than steel and twice as stiff. Composed mostly of carbon atoms bonded together into crystals, a single carbon fiber is typically 5 to 10 microns (0.00020–0.00039 in) in diameter (for comparison, a single strand of spiderweb silk is usually between 3 to 8 microns thick). When several thousand carbon fibers are bundled together, it forms a “tow”—a thread that may be used by itself or woven into a fabric.

Like G-10, layers of carbon fiber fabric can be impregnated with epoxy, stacked, and cured under pressure and heat. This can be done in a mold to create a part of a particular shape or in a flat press to create the flat carbon fiber sheet used for knife handle scales. Although carbon fiber is black, more recently a number of material manufacturers have added metal, ceramic, and other materials to create dramatic colored patterns.

Carbon fiber is extremely strong, rigid, dimensionally stable, and lightweight. It is also durable, resistant to chemicals and corrosion, electrically conductive, and invisible to X-rays. Since carbon fiber tow can be woven into many different patterns, it offers a stunning appearance and visual variety. Like G-10, carbon fiber sheet can also be manufactured with a “peel ply” top layer that provides increased texture. Unfortunately, all these remarkable qualities don’t come cheap. Although specific material costs vary, in general, carbon fiber sheet costs about five times as much as the same size sheet of G-10.

Because of the high cost of carbon fiber sheet, using it as a handle material can have a dramatic impact on the ultimate price of a knife. For this reason, laminate manufacturers have borrowed a page from furniture makers. For literally thousands of years, furniture has been made using a thin veneer of hardwood glued over a less-expensive solid-wood base material. This approach provides a sturdy piece of furniture with the beauty of hardwood at a much more affordable price.

In this same spirit, a thin layer of carbon fiber sheet can be laminated to a base layer of G-10 to create a scale material. Since both layers are dimensionally stable and strong, there is no discernable difference in the performance of the scale material and its external appearance still showcases the qualities of carbon fiber. From a cost perspective, however, the price of the knife can be kept much more affordable than if its scales were made from solid carbon fiber sheet.

Aluminum is a non-ferrous metal that is lightweight, strong, corrosion-resistant, ductile, and easy to machine into intricate detail. The most abundant metal in the Earth’s crust, it is also easily alloyed with other metals, including iron, copper, manganese, silicon, magnesium, titanium, chromium, and zinc to achieve specific performance properties.

For knife handles, the most commonly used aluminum is 6061-T6, a medium to high-strength heat-treatable alloy. In addition to its excellent machining and finishing qualities, T6 is also very suitable for color anodizing, an electrochemical process that can be used to create durable coatings in a broad spectrum of colors.

Stainless steel is an extremely strong, corrosion-resistant material that makes an excellent knife handle. Unlike blade steels, the stainless steel suitable for knife handles has a very low carbon content and is significantly softer. It takes an excellent finish and provides a great canvas for engraving and other aftermarket embellishment; however, it will show scratches and develop considerable “character” with extended carry and use. Compared to other handle materials, stainless steel is also relatively heavy and does not provide much grip texture. The original handle material of Spyderco’s earliest knives, it is still a sentimental favorite and the choice of end users who prefer greater “heft” in their knives.

Titanium has the highest strength-to-density ratio of any metallic element. It is also extremely corrosion-resistant, paramagnetic (very weakly attracted by the poles of a magnet, but not retaining any permanent magnetism), and has relatively low thermal and electrical conductivity. Pure titanium is classified into six different grades, but it is more commonly combined with other metals to yield four varieties of titanium alloys. These alloys typically contain trace amounts of aluminum, vanadium, molybdenum, niobium, tantalum, zirconium, manganese, iron, chromium, cobalt, nickel, and copper.

For knife handles, the most commonly used titanium alloy is 6AL-4V, which is enhanced with aluminum and vanadium, as well as carbon, iron, nitrogen, oxygen, and hydrogen. This alloy recipe makes it much stronger than commercially pure titanium, while retaining the same stiffness and most of the same thermal properties. Very importantly, it allows it to be heat treated to enhance its strength, toughness, and dimensional stability.

The most common use of titanium in knife handles is in folders featuring the Reeve Integral Lock (R.I.L.) mechanism, which was popularized by renowned knifemaker Chris Reeve. Similar in operation to Michael Walker’s LinerLock, it uses an integrally machined lock bar instead of a separate liner. It also takes advantage of one of titanium’s other properties—its ability to gall or “stick” to other metals under pressure. This property promotes strong engagement of the titanium lock bar with the ramp on the blade’s tang.

Titanium offers the same strength as steel, but in a material that is 45 percent lighter. It can be intricately machined while maintaining exceptional structural strength and can be heat treated to enhance its hardness. It can be polished, bead blasted, and tumbled to create a variety of attractive finishes and is also well suited to anodizing, nitriding, and other specialized coatings.

Once again, these remarkable properties are not inexpensive. Extracting titanium from its various ores is costly and laborious, as are the processes of alloying it and rendering it into readily usable form. When you crunch the numbers, titanium is generally about 35-50 times more expensive than stainless steel.

FRN is a nylon-based plastic that is reinforced with glass fibers. While pure nylon can be easily injection molded to shape, it does not withstand heat or ultraviolet light well, so it is often modified to improve its specific properties. Adding glass fibers to the nylon creates “glass-filled” or “fiberglass-reinforced” nylon, which offers increased rigidity and dimensional stability, improved hardness, and superior tensile strength. Unlike other materials, which often come in limited color choices, FRN can also be dyed to create almost any color imaginable.

The use of injection-molded nylon to create knife handles goes back at least to the 1960’s and the Hackman Camp Knife. A non-flipping form of butterfly knife called the Linkkupuukko ("latch-knife") in Finnish, this curious knife was marketed by Hackman as a retkiveitsi ("camping knife") and later as Eräpuukko ("wilderness puukko"). According to military historians, Hackman Camp Knives were also issued to some CIA operatives during the Vietnam War.

In 1981, legendary knife designer Blackie Collins redesigned Gerber’s FS1 folding knife to incorporate a one-piece, injection-molded handle made from Zytel®, a glass-filled nylon material developed by DuPont®. The resulting knife—the LST (for “Light, Strong, Tough”)—revolutionized modern folding knife design. In 1990, Spyderco revolutionized it again by adding an integrally molded pocket clip. Our original Endura® and Delica® models combined injection-molded FRN construction with the advantages of our CLIPIT® platform to set a new standard in lightweight, affordable, everyday-carry cutting tools.

Although nylon can be dyed practically any color, in solid parts it is an opaque material. When Spyderco began developing the Manix® 2 Lightweight, one of our goals was to make the handle transparent or translucent to highlight its internal mechanism. To do that, we had to find a different injection-moldable material that offered the same advantages as FRN, but was clear or translucent.

Working in close cooperation with leading plastics experts, we chose fiberglass-reinforced copolymer (FRCP) as the best material for the Manix 2 Lightweight project. Copolymers are substances created by chemically combining two or more simple compounds (monomers) into a long chain of molecules. The exact chemistry of this process and the specific molecular structures it creates can be manipulated to combine the desirable qualities of the simple compounds. For example, one compound may offer strength and resistance to weathering and chemicals, but not accept dyes well. When combined with another compound that can be readily dyed, the resulting copolymer offers the best qualities of both.

This was the exact process we used to fine-tune the attributes of the FRCP used in the Manix 2 Lightweight’s handle. The result was a lightweight, translucent material that could be injection molded into the handle’s desired shape, while still meeting our demanding standards of strength and durability.

Natural rubber is made from the milky sap of the rubber tree, called latex, and processed for a variety of manufacturing uses. Widespread commercial demand for rubber later led to the development of modern synthetic elastomers, like Kraton®.

Kraton is an extremely versatile material for knife handles because it is resilient, durable, and moisture-resistant. It can be readily injection molded into complex shapes and offers an excellent non-slip texture. Kraton can be used in grip panels supported by other materials or molded to form complete knife handles.

Polypropylene is a versatile, lightweight thermoplastic polymer. It has an excellent strength-to-weight ratio, high heat tolerance, and is resistant to most chemicals. Widely used in manufacturing for food-safe containers, medical devices, and packaging, it also makes an excellent knife handle. Polypropylene can be dyed to achieve a wide range of colors and can be injection-molded to create intricate patterns and non-slip textures.

This is by no means an exhaustive list of all possible knife handle materials. Other natural materials, including stag, pearl, abalone, coral, and leather, as well as other man-made synthetic materials, have all been successfully used to craft knife handles. Hopefully, however, this overview gives you an insight into the most common handle materials, their pros and cons, and the complex economics of hafting a factory-made knife.