What Is Mortise Lock? Installation Of Mortise Lock
What Is Mortise Lock?
A mortise lock is a type of lock that requires a pocket, called a mortise, to be cut into the door or furniture where the lock will be installed. While they were once more common in older buildings before cylindrical locks became popular, they are now making a comeback in higher-end residential and commercial construction in the US. In Europe, however, mortise locks are still widely used in homes of all ages.
History Of Mortise Lock
Mortise locks have been a staple in door hardware systems in the US since the mid-18th century. At the time, these locks were combined with door pulls to open the door when unlocked. Over time, the pulls were replaced by knobs.
In the early days, mortise locks were only used in the most luxurious homes and the most formal rooms. The other rooms used box locks or rim locks, which are self-contained units attached to the surface of the door, unlike mortise locks which are embedded in the door itself.
One of the earliest examples of the use of both mortise and rim locks in a single home can be seen at Thomas Jefferson’s Monticello. In 1805, Jefferson wrote to his joiner asking for locks for his home, where he specified that the closets were to be fitted with rim locks, while 26 mortise locks were to be used in the main rooms.
Trade catalogues of the early 19th century featured depictions of different mortise lock hardware, including lock mechanisms, escutcheon plates, and door pulls. However, these locks were still expensive and difficult to obtain, with Jefferson ordering his locks from Paris.
The same pattern can be seen at Decatur House in Washington D.C. where mortise locks were used in the primary rooms and rim locks in closets and secondary spaces.
At Monticello, the mortise locks used were warded locks, which were widely used in Europe from the medieval period until the early 19th century. The term “warded lock” refers to the lock mechanism, while “mortise lock” refers to the location of the bolt.
These locks were secured by a series of obstructions within the lock box, and a key with matching cutouts was required to turn the lock and open the latch.
Three British locksmiths, Robert Barron, Joseph Bramah, and Jeremiah Chubb, played a crucial role in the development of modern lever tumbler locks, with Chubb’s lock being patented in 1818.
The term “lever tumbler lock” refers to the lock mechanism, so a lock can be both a mortise lock and a lever tumbler lock. The key moves a series of levers to allow the bolt to move in the door.
The next major development in mortise locks came in 1865 with Linus Yale Jr.’s pin tumbler mortise cylinder lock, which moved the tumblers, latch or bolt, and the bolt mechanism inside the door, as opposed to the previous designs where the lock mechanism was always on the outside.
This allowed for shorter keys, as they no longer had to reach all the way through the door. Pin tumbler locks are still the most widely used type of mortise lock today.
Installation Of Mortise Lock
A mortise lock can be installed by a homeowner with basic woodworking skills and knowledge. The use of a dedicated mortising jig makes the cutting of the pocket an easy task, but inexperienced installers may struggle with the external trim.
Despite weakening the structure of a timber door, a mortise lock is stronger and more versatile than the newer bored cylindrical lock. The newer lock format lacks the physical volume and mechanical stability required for heavy knobs and levers, while the mortise lock can accommodate a heavier spring and more substantial internal mechanism.
Mortise locks are available in various security configurations and are commonly used in industrial, commercial, and institutional settings. They also accept a range of standardized cylinders and accessories from various manufacturers, allowing for architectural and functional conformity.
Major manufacturers in the US include Accurate, Arrow, Baldwin, Best, Corbin Russwin, Emtek, Falcon, Penn, Schlage, Sargent, and Yale. Distributors like Nostalgic Warehouse offer decorative trim and accessories to enhance the appearance of the lock. European manufacturers are also gaining wider acceptance and use.
Mechanism Of Mortise Lock
A mortise lock is a type of lock that is typically installed on doors. It consists of several components that work together to secure the door. The most basic form of a mortise lock is called a dead lock, which has no handle or latch.
A more advanced version of a mortise lock is called a sash lock, which includes a non-locking sprung latch that is operated by a door handle.
Historically, mortise locks used lever locks as their mechanism, but more recently the use of Euro cylinder locks, which use a pin tumbler lock in a mortise housing, has become more common. In the United States, the typical components of a mortise lock installation include the lock body, the lock trim, the strike plate or box keep, and the keyed cylinder.
The lock body is installed inside the mortise cut-out in the door, the lock trim can be any number of designs, and the strike plate reinforces the cavity in the door jamb or frame.
