The Linerlock is a locking mechanism for folding pocket knives. A Linerlock is a folding knife with a side-spring lock that can be opened and closed with one hand without repositioning the knife in the hand. The lock is self-adjusting for wear. The modern Linerlock traces its lineage to the late 19th century, but in the 1980s the design was improved by American custom knifemaker Michael Walker.
Linerlock knives have been around since the late 19th century. The Cattaraugus liner locking patent, 825,093 was issued on July 3, 1906. After 1923 when the patent expired, it was used by other manufacturers such as in the common military and lineman's issue two-blade electrician’s knife; the Camillus TL-29 for the locking screwdriver-stripper blade, until 2007 when the Camillus Cutlery Company went out of business. [1]
Walker refined and popularized the design, [2] [3] eventually securing a trademark [4] for the name "Linerlock" in March 1990. [5] [6] Walker's improvement to the design was to facilitate true one handed opening of the knife. [7] This was accomplished by removing the weak back spring and adding a heat-treated stop pin to align the blade in the open position. [7] Walker added a detent ball to hold the blade in the closed position using the same spring force from the liner. [7] [8]
Linerlock mechanisms are most commonly composed of titanium alloy or steel. [8] The linerlock's locking side liner is split from the top toward the bottom, similar to an automotive leaf spring (also called a lock bar) that butts up against the tang of the blade to prevent the blade from closing. [9] In an interview with Blade in 1988, Walker stated, “This long leaf-spring effect cuts down on stress on the locking mechanism". [9] As the lock on the original electrician's knife was mostly to hold a screwdriver blade open (the knife blade, itself was secured by a slip joint method), Walker's refinements prevented the knife blade from closing on the user's hand and converted it into a true lock. [8] [10]
To release the lock, the user presses the lock bar back toward the handle side, at which time the blade is free to close. In the closed position the lock bar (leaf spring) rests alongside the handle and the blade. [9]
There are a number of other variations on the Linerlock or locking liner, depending on the knife manufacturer. One example would be the frame lock, sometimes called the Reeve Integral Lock and used on the Sebenza. With the "frame lock," the frame rather than the liner acts like the leaf spring/lock bar. Another variation, known as the inset Linerlock has the leaf spring embedded into the plastic scales of the handle, technically forgoing a metal liner. Kershaw Knives uses "a pin-and-dimple lock" on a knife designed by custom knifemaker RJ Martin called the "Nerve" to keep the blade closed. [11]
Some of the many knife makers and knife manufacturing companies that utilize the Linerlock, in alphabetical order, include:
A knife is a tool or weapon with a cutting edge or blade, usually attached to a handle or hilt. One of the earliest tools used by humanity, knives appeared at least 2.5 million years ago, as evidenced by the Oldowan tools. Originally made of wood, bone, and stone, over the centuries, in step with improvements in both metallurgy and manufacturing, knife blades have been made from copper, bronze, iron, steel, ceramic, and titanium. Most modern knives have either fixed or folding blades; blade patterns and styles vary by maker and country of origin.
A pocketknife is a knife with one or more blades that fold into the handle. They are also known as jackknives (jack-knife), folding knives, EDC knife, or may be referred to as a penknife, though a penknife may also be a specific kind of pocketknife. Blade lengths typically range from 5 to 15 centimetres. Some pocketknives have multiple tools in addition to one or more blades.
The Camillus Cutlery Company was one of the oldest knife manufacturers in the United States as its roots date back to 1876. The Company produced millions of knives until it filed for bankruptcy in 2007. Its brand name and intellectual property rights were purchased by Acme United Corporation, which re-launched the Camillus brand in May 2009 using modern materials.
Spyderco is an American cutlery company based in Golden, Colorado, producing knives and knife sharpeners. Spyderco pioneered many features that are now common in folding knives, including the pocket clip, serrations, and the opening hole. Spyderco has collaborated with 30 custom knife makers, athletes, and self-defense instructors for designs and innovated the usage of 20 different blade materials.
An assisted-opening knife is a type of folding knife which uses an internal mechanism to finish the opening of the blade once the user has partially opened it using a flipper or thumbstud attached to the blade.
Ernest R. Emerson is an American custom knifemaker, martial artist, and edged-weapons expert. Originally an engineer and machinist in the aerospace industry, Emerson became a knifemaker by producing knives for a martial arts class and making art knives early in his knifemaking career. In the 1980s he became better known for his combat knives and popularizing a style of knife known as the Tactical-folder.
Blade is a consumer magazine about knife collecting. The magazine is based in Appleton, Wisconsin.
Ken Onion is an American custom knifemaker based in Kaneohe, Hawaii, United States who invented the "SpeedSafe" assisted opening mechanism for Kershaw Knives. Ken Onion was the Premier Knife Designer for Kershaw Knives.
Cold Steel, Inc. is an American retailer of knives/bladed tools, training weapons, swords and other martial arts edged and blunt weapons. Founded in Ventura, California, the company is currently based in Irving, Texas after an acquisition by GSM Outdoors in 2020. Cold Steel products are manufactured worldwide, including in the United States, Japan, mainland China, Taiwan, India, Italy and South Africa.
SHARPFINGER® is a brand of knife modeled after the Schrade 152 OT. The SHARPFINGER trademark is designated to a variety of knives in this design by a number of makers.
Chris Reeve Knives is an American knife manufacturing corporation with international sales and distribution headquartered in Boise, Idaho, that designs, develops, and sells folding pocket knives and fixed-blade knives. Its products include the Sebenza, Inkosi, Umnumzaan, TiLock, Mnandi folding knives, Impinda slip joint, and the Green Beret, Pacific, Professional Soldier, Nyala, and Sikayo fixed blade knives. Chris Reeve Knives' industry contributions include the Integral Lock, contributions to the blade steels CPM-S30V and CPM-S35VN, and has won Blade Magazine's Blade Show Manufacturing Quality Award 15 times. Their motto is Think Twice, Cut Once.
Columbia River Knife & Tool, Inc. (CRKT) is an American knife company established in 1994, and currently based in Tualatin, Oregon, United States. The company's president and sales executive is Rod Bremer and the finance executive is Peggy Bremer.
The CQC-6 or Viper Six is a handmade tactical folding knife with a tantō blade manufactured by knifemaker Ernest Emerson. Although initially reported as the sixth design in an evolution of fighting knives and the first model in the lineup of Emerson's Specwar Custom Knives, Emerson later revealed that the knife was named for SEAL Team Six. It has a chisel-ground blade of ATS-34 or 154CM stainless steel and a handle made of titanium and linen micarta. The CQC-6 is credited as the knife that popularized the concept of the tactical folding knife.
The SARK or NSAR is a folding knife designed by knifemaker Ernest Emerson for use as a search and rescue knife by the US military. It has a hawkbill with a blunt tip in order to cut free trapped victims without cutting them in the process. There is a variant with a pointed-tip designed for police, known as the P-SARK.
Michael Leon Walker is an American custom knifemaker and sculptor based in Taos, New Mexico. Walker is the inventor of more than 20 different knife mechanisms including the Walker Linerlock for which he secured a trademark in 1980.
A fighting knife has a blade designed to most effectively inflict injury in close-quarters physical confrontations. The combat knife and the trench knife are examples of military fighting knives.
Walter Wells "Blackie" Collins was an American knife maker who designed and popularized the assisted opening mechanism and various automatic knife designs within the art of knifemaking. He is cited by other knifemakers and collectors as one of the most innovative knife designers in the world and was an author and the founder of what became Blade Magazine. Collins died July 20, 2011 in a motorcycle accident near North, South Carolina.
Robert G. Terzuola is an American knife maker who popularized the type of knife known as the tactical folding knife.
The Blade Show is an annual tradeshow for the cutlery industry. It is the largest event of its type in the world. The show is owned by Caribou Media Group and is hosted by Blade Magazine. The event has over 1,000 exhibitors and is the host for inductees into the annual Cutlery Hall of Fame. It also hosts the annual Blade HQ Balisong Competition, BladeSports International Cutting World Championships, Blade University, Knife of the Year Awards, and a variety of knifemaking classes and demos. The event takes place every year over the course of several days and brings in knifemakers and knife companies from all parts of world.
Mike Snody is a Southern Texas knife maker who is known for his use of exotic materials in his custom knives. He is currently based in Walsenburg, Colorado.