Part 4: Handle Materials
Alright, we're up to part 4 - handles and handle materials. Besides providing decorative touches, handle materials can also contribute significantly to the stiffness and overall build of a knife. Some materials like carbon fiber and bone are only used as decorative handles on top of steel liners for strength reasons, while other materials, such as G10, FRN and Micarta can be used with or without steel reinforcement.
Again, before we start just some vocabulary:
Liners: When we call a handle "lined" or "unlined" it means whether or not there are reinforcing steel liners have been placed in the knife handle. In some case they provide structure to prevent the force of the lock from torquing the knife, in other cases they provide ductile strength to prevent handle materials from cracking under stress. Nested liners are hidden, generally in cutouts in the handle. Unnested liners are generally not hidden. All slipjoint knives employe steel liners to prevent the backsprings from moving out of place.
Nylon and Nylon Composite Handles
Nylon/Thermoplastic: A basic, heat-formed hardened plastic, pure nylon or thermoplastic handles are rarely if ever used. They tend to lack any kind of toughness or wear resistance, and as such are easily damaged through abuse. Only found on the very cheapest of knives, or, paradoxically, on some high-end survival knives where handle strength is of limited concern.
Fibreglass Reinforced Nylon (AKA FRN, Glass-Reinforced Nylon, Zytel, Grivory, Valox): Probably the most popular handle material used for making pocket knives, FRN uses fibreglass reinforcement to add strength and wear resistance to nylon. This type of handles material has some very significant advantages: It's inexpensive to make and machine, it's highly resistant to wear, shock, acid, damage and abrasion, as well as being extremely resistant to temperature changes.
There are a couple of downsides to FRN, however. The major issue with most forms of FRN (though specific formulations may change this) is that they lack hardness - they're tough, but extremely flexible. As such, FRN often needs some sort of stiffening element such as aluminium or steel liners to support the stresses of the lock. FRN is also diffcult to texture for grip and in many people's minds, feels cheap. FRN remains one of the most popular handle materials for knives.
G10: G10 is another extremely popular handle material use to make knife handles. G10 is actually an epoxy resin laminate of fibreglass reinforced nylon, and as such has many of the major advantages, including resistance to wear, temperature, abrasion and acid. G10, being a layered material, is also much easier to texture using CNC machining techniques. G10 also has signficantly more structural hardness than FRN. In essence, G10 is FRN that's been cut in to extremly thin strips, and then laminated together using an epoxy. G10 IS nominally FRN, but with an extra manufacturing process.
There are some negatives to G10, however. G10 can be extremely brittle and as such generally requires some sort of strengthening element to prevent cracking with use (not always the case - some Cold Steel knives have G10-only handles). Since G10 doesn't flex, it can also create "hot spots" in grip if not designed properly - spots in the grip that become painful after prolonged usage.
Metal Handles
Stainless Steel: Generally made from 410-series or 300 series stainless steel, stainless steel handles are a popular choice for knives that are made to be extremely thin, use frame locks, or for gentleman's knives. Properly hardened steel has many useful properties, including high wear resistance, structural strength, toughness and looks. Stainless steel also rarely has the "hot spot" problem inherent with G10.
There are many negatives with stainless steel handles, however. Weight is a prime concern. Grip is also a major issue, as texturing stainless steel to provide grip often leads to corrosion issues. This problem is generally fixed with some sort of rubber handle insert. Stainless steel are also sensitive to temperature changes and can warp.
Titanium: Used on higher-end production knives and custom folders, titanium is generally used in place of stainless steel in making handles. It has many of the benefits of stainless steel, with the major improved benefit is that titanium (and many of it's alloys) are impervious to corrosion.
Titanium also has many of the major negative issues of stainless steel, including decreased grip, sensitivity to temperature chances and warping. Titanium, due to it's flexibility, also generally needs to be much thicker than a comparable stainless steel handle to provide the same strength, which generally does away with any desired weight gains. Last but certianly not least, titanium does not have the wear resistance of stainless steel, so lock components made of titanium will wear and fail MUCH faster than those made of steel.
Aluminum: Aluminum has again many of the major benefits of stainless steel, but is considerably lighter.
The major negative point to aluminum is that it does not have the structural strength to make a lock out of the material. Generally knives that use aluminum handles will use nested steel liners to create the lock components. Aluminum also scratches extremely easily.
Other Composite Handles
Micarta: A trademarked name, micarta actually refers to an exposy resin composite made of fibrous, natural materials in sheet form. As such, it's possible to have paper micarta, denim micarta, canvas micarta or any number of other choices, including rarer forms such as silk micarta (normally made of parachute silk) or carbon fiber micarta. Micarta is generally used for looks in a handle material and generally includes some sort of strengthening liner. It otherwise has many of the benefits of FRN, including resistance to acid, abrasion and temperature changes.
There are many negative points to micarta, however. Because of the difference in materials used, micarta is difficult to form and machine. The material is extremely finicky in machining and generally requires some sort of final polishing stage done by hand (which significantly increases cost). Micarta tends to be brittle and will crack if great care is not taken in production (such as drilling holes for screws), and is susceptible to breakage from normal wear and tear.
Pakkawood (aka Dymondwood): Pakkawood, not a real wood, is in fact a compressed expoxy mixed with sawdust to create a machinable handle. Pakkawood can be "brushed" during production to create the appearance of wood grain, and takes dyes extremely easily. Generally pakkawood is machined and then finished with some sort of lacquer after dying. Pakkawood can also be laminated to create a multicolor effect. Pakkawood is an extremely strong, extremely stable material the can be used alone to create knife handles without strengthening liners. Pakkawood is so stable in usage that it's an acceptable handle material the world over for creating chef's knives for working in restaurants.
The major negative point to pakkawood is that like real wood, it can be damaged with enough force and as such is rarely used in hard working knives. Some people also find it really cheesy looking. Dymondwood, a trademarked form of pakkawood, adds thermoplastic elements to the sawdust to increase the tensile strength of the material.
Carbon Fiber: Carbon fiber is generally used for looks alone, as it lacks the requisite structural strength to form a handle material on it's own. It is also extremely difficult to texture for grip and can be prohibitively expensive. Carbon Fiber dust is also poisonous, making the material difficult to work with.
Natural Materials
Wood: Wood's been used a knife handle for many, many hundreds of years, and that practice continues today. Mostly wood is used for looks, or wear significant handle strenght is not a huge concern (mostly used on fixed blade knives and not folders). When wood is used on folding knives it's always attached to some sort of metal liner. Wood is extremely tough, easily found and easily shapable, and finished properly it can be very beautiful.
Wood can also crack or rot, or dry out if not cared for properly. Just about all wood-handled knives on the market are pre-finished to help prevent these types of problems.
There are two types of wood handles on the market, stabilized and unstabilized. Stabilized wooden handles are generally soaked in water to remove the oils, and then soaked or injected with some sort of stabilizing resin for long-term wear resistance. This is extremely popular for knives used in bushcrafting or survival work. Unstabilized wood handles use kiln-dried wood covered in a lacquer, and is common on custom made knives.
Bone: Another material that's been used for many years to make knife handles, bone is generally used to makes scales (decorative or grip elements) rather than the entire handle as bone tends to dry up and lose tensile strength over time. Jigged or burnt bone handles are common on slipjoint knives and custom made knives.
Antler: Generally made from the antlers of the Indian Sambar, antler handles are another classic knife scale material. Like bone they tend to lose tensile strength as they age and as such are used only for decorative elements. Antler handles are also made from reindeer, white-tailed deer and other more common species of deer. In Africa it's common to make knife handles from antelopes such as Kudu or Rhebok.
And here ends part 4!
