A mortise lock (also spelled mortice lock in

British English British English (BrE, en-GB, or BE) is, according to Lexico, Oxford Dictionaries, "English language, English as used in Great Britain, as distinct from that used elsewhere". More narrowly, it can refer specifically to the English language in ...

) is a

lock Lock(s) may refer to: Common meanings *Lock and key, a mechanical device used to secure items of importance *Lock (water navigation), a device for boats to transit between different levels of water, as in a canal Arts and entertainment * ''Lock ...

that requires a pocket—the mortise—to be cut into the edge of the

door A door is a hinged or otherwise movable barrier that allows ingress (entry) into and egress (exit) from an enclosure. The created opening in the wall is a ''doorway'' or ''portal''. A door's essential and primary purpose is to provide security b ...

or piece of

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into which the lock is to be fitted. In most parts of the world, mortise locks are found on older

building A building, or edifice, is an enclosed structure with a roof and walls standing more or less permanently in one place, such as a house or factory (although there's also portable buildings). Buildings come in a variety of sizes, shapes, and fun ...

s constructed before the advent of bored cylindrical locks, but they have recently become more common in commercial and upmarket residential construction in the United States. The design is widely used in domestic properties of all vintages in Europe.

History

Mortise locks have been used as part of door hardware systems in the US since the second quarter of the eighteenth century. In these early forms, the mortise lock mechanism was combined with a pull to open the unlocked door. Eventually, pulls were replaced by knobs. Until the mid-nineteenth century, mortise locks were only used in the most formal rooms in the most expensive houses. Other rooms used box locks or

rim lock A rim lock is a locking device that attaches to the surface of a door. It is the oldest type of lock used in the United Kingdom and Ireland. It is of a basic design using (usually) a single lever and a sliding bolt. Wards can be used for addi ...

s; in contrast with embedded mortise locks, the latch itself is in a self-contained unit that is attached to the surface of the door. Rim locks have been used in the United States since the early eighteenth century. An early example of the use of mortise locks in conjunction with rim locks within one house exists at

Thomas Jefferson Thomas Jefferson (April 13, 1743 – July 4, 1826) was an American statesman, diplomat, lawyer, architect, philosopher, and Founding Fathers of the United States, Founding Father who served as the third president of the United States from 18 ...

Monticello Monticello ( ) was the primary plantation of Founding Father Thomas Jefferson, the third president of the United States, who began designing Monticello after inheriting land from his father at age 26. Located just outside Charlottesville, V ...

. In 1805, Jefferson wrote to his

joiner A joiner is an artisan and tradesperson who builds things by joining pieces of wood, particularly lighter and more ornamental work than that done by a carpenter, including furniture and the "fittings" of a house, ship, etc. Joiners may work in ...

listing the locks he required for his home. While closets received rim locks, Jefferson ordered 26 mortise locks for use in the principal rooms. Depictions of available mortise lock hardware, including not only lock mechanisms themselves but also escutcheon plates and door pulls, were widely available in the early nineteenth century in trade catalogues. However, the locks were still expensive and difficult to obtain at this time. Jefferson ordered his locks from Paris. Similarly, mortise locks were used in primary rooms in 1819 at

Decatur House Decatur House is a historic house museum at 748 Jackson Place in Washington, D.C., the capital of the United States. It is named after its first owner and occupant Stephen Decatur. The house (built, 1818) is located at the northwest corner of ...

in Washington, DC while rim locks were used in closets and other secondary spaces. Warded locked

The mortise locks used at Monticello were

warded lock A warded lock (also called a ward lock) is a type of lock that uses a set of obstructions, or ''wards'', to prevent the lock from opening unless the correct key is inserted. The correct key has notches or slots corresponding to the obstructions in ...

s. The term "warded lock" refers to the lock mechanism, while the term "mortise lock" refers to the bolt location. Warded locks contain a series of static obstructions, or wards, within the lock box; only a key with cutouts to match the obstructions will be able to turn freely in the lock and open the latch.Bill, Phillips. The Complete Book of Locks and Locksmithing. pp. 60, 62. Warded locks were used in Europe throughout the medieval period and up until early 19th century. Three British locksmiths,

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Joseph Bramah Joseph Bramah (13 April 1748 – 9 December 1814), born Stainborough Lane Farm, Stainborough, in Barnsley, Yorkshire, was an English inventor and locksmith. He is best known for having improved the flush toilet and inventing the hydraulic pr ...

, and

Jeremiah Chubb A Chubb detector lock is a lever tumbler lock with an integral security feature, a re-locking device, which frustrates unauthorised access attempts and indicates to the lock's owner that it has been interfered with. When someone tries to pick th ...

, all played a role in creating modern lever tumbler locks. Chubb's lock was patented in 1818. Again, the term refers to the lock mechanism, so a lock can be both a mortise lock and a lever tumbler lock. In the modern lever tumbler lock, the key moves a series of levers that allow the bolt to move in the door. Pin tumbler with key

The next major innovation to mortise lock mechanisms came in 1865.

Linus Yale, Jr. Linus Yale Jr. (April 4, 1821 – December 25, 1868) was an American mechanical engineer, manufacturer, and co-founder with Henry R. Towne of the Yale Lock Manufacturing Company, which became the premier manufacturer of locks in the United ...

's pin tumbler mortise cylinder lock put not only the latch or bolt itself inside the door, but also the tumblers and the bolt mechanism. Up to this point, the lock mechanism was always on the outside of the door regardless of the bolt location. This innovation allowed keys to be shorter as they no longer had to reach all the way through a door. Pin tumbler locks are still the most common kind of mortise lock used today.

Mechanism

Mortise locks may include a non-locking sprung latch operated by a door handle. Such a lock is termed a sash lock. A simpler form without a handle or latch is termed a dead lock. Dead locks are commonly used as a secure backup to a sprung non-deadlocking latch, usually a pin tumbler rim lock.The type commonly called a "Yale" lock. Mortise locks have historically, and still commonly do, use

lever lock A lever is a simple machine consisting of a beam or rigid rod pivoted at a fixed hinge, or ''fulcrum''. A lever is a rigid body capable of rotating on a point on itself. On the basis of the locations of fulcrum, load and effort, the lever is div ...

s as a mechanism. Older mortise locks may have used warded lock mechanisms. This has led to popular confusion, as the term "mortise lock" was usually used in reference to lever keys in traditional European terminology. In recent years the

Euro cylinder The pin tumbler lock is a lock mechanism that uses pins of varying lengths to prevent the lock from opening without the correct key. Pin tumblers are most commonly employed in cylinder locks, but may also be found in tubular pin tumbler locks (al ...

lock has become common, using a pin tumbler lock in a mortise housing. The parts included in the typical US mortise lock installation are the lock body (the part installed ''inside'' the mortise cut-out in the door); the lock trim (which may be selected from any number of designs of

doorknob A door handle or doorknob is a handle used to open or close a door. Door handles can be found on all types of doors including exterior doors of residential and commercial buildings, internal doors, cupboard doors and vehicle doors. There are many ...

lever A lever is a simple machine consisting of a beam or rigid rod pivoted at a fixed hinge, or '' fulcrum''. A lever is a rigid body capable of rotating on a point on itself. On the basis of the locations of fulcrum, load and effort, the lever is d ...

s, handle sets and pulls); a

strike plate This is a glossary of locksmithing terms. Glossary References External links {{Locksmithing Locksmithing Locksmithing is the science and art of making and defe ...

(or box keep), which lines and reinforces the cavity in the door jamb or frame into which the bolt fits; and the keyed cylinder which operates the locking/unlocking function of the lock body.

Selection and installation

The installation of a mortise lock can be undertaken by an average homeowner with a working knowledge of basic

woodworking Woodworking is the skill of making items from wood, and includes cabinet making (cabinetry and furniture), wood carving, woodworking joints, joinery, carpentry, and woodturning. History Along with Rock (geology), stone, clay and animal parts, ...

tools and methods. Many installation specialists such as carpenters use a dedicated mortising jig which makes precise cutting of the pocket a simple operation, but the subsequent installation of the external trim can still prove problematic if the installer is inexperienced. Although the installation of a mortise lock actually ''weakens'' the structure of the typical timber door, the embedded lock is typically stronger and more versatile than the newer bored cylindrical lock format, both in external trim, and functionality. Whereas the newer mechanism lacks the physical volume and mechanical stability required for ornate and solid-cast knobs and levers, the mortise lock can accommodate a heavier return spring and a more substantial internal mechanism. Mortise locks are available in a wide range of functional security configurations, and are widely installed in industrial, commercial, and institutional environments. Furthermore, a typical mortise lock typically accepts a wide range of other standardized manufacturers' cylinders and accessories, allowing architectural and functional conformity with other lock hardware already on site. Manufacturers of mortise locks in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

include Accurate, Arrow, Baldwin, Best, Corbin Russwin,

Emtek Products, Inc Emtek Products is a door and cabinet hardware manufacturer based in the City of Industry, Los Angeles County. They are a subsidiary of Swedish company Assa Abloy. The brand produces a range of residential lock products, including tubular lock ...

, Falcon, Penn,

Schlage Schlage (pronounced ) is an American lock manufacturer founded in 1920 by Walter Schlage. Schlage was headquartered in San Francisco from its inception until it relocated to Colorado Springs, Colorado in 1997. Schlage also produces high-securi ...

, Sargent, and

Yale Yale University is a private research university in New Haven, Connecticut. Established in 1701 as the Collegiate School, it is the third-oldest institution of higher education in the United States and among the most prestigious in the wor ...

. Distributors such as Nostalgic Warehouse carry a wide range of decorative trim and accessories to dress up the appearance of a lock installation. Also, many European manufacturers whose products had previously been restricted to "designer" installations have recently gained wider acceptance and use.

Notes

References

*Peter Brett. ''Carpentry and Joinery'' Nelson Thornes, 2004.

External links

* http://www.lockwiki.com/index.php/Main_Page {{Locksmithing Locks (security device) Door furniture