What Is a Mortise Lock – Understanding the Core of Door Security | All Security Equipment

As burglars continue to get access to more sophisticated lock-picking tools like universal master keys, the need for homeowners like you to secure their properties with more complex, high-security locks like the mortise lock remains ever-prevalent.

The mortise lock, also spelled as the mortice lock, is known as a mystery lock among locksmiths, and it’s for a good reason.

We curated this article to help demystify the mortise lock and give you several reasons to have one or more mortise lock sets installed at your property.

What Is a Mortise Lock?

The mortise lock gets its name from the nature of its installation. Mortise locks are door locks that are installed in a dedicated lock pocket situated in the thickness of a door. This pocket is also known as the mortise or mortice, depending on who you ask.

Since a mortice door can only be installed in a door with considerable thickness, it is typically not found in internal doors but is ubiquitous in entrance doors. However, many modern internal doors provide adequate thickness for

Mortice locks have been in existence for a very long time and are mostly found in older constructions and properties, as they predate bored cylindrical locks. However, many commercial and modern residential properties in the United States now feature mortise lock sets in their doors.

Mortise locks are now found in commercial door hardware due to the heightened security that they offer.

How Does a Mortise Lock Work?

Mortise locks (or mortice locks) are known as mystery locks because of how the lock mechanisms are typically hidden within the pockets created for them along the edge of the doors on which they are installed.

The lock mechanism of a mortise lock consists of a large, flat compartment that the bolt system retreats into, connecting levers that connect to the bolt via bolt stops, strike plates to help protect the door material, the face plate that surrounds the mortise, and the escutcheon plates that helps maintain the door’s aesthetics.

The simplest explanation of how a mortise lock works is that it relies on a key and, in some cases, a handle to retract or extend its bolts, which enter the opposing holds and lock the door.

A professional locksmith should carry out the installation of a mortise lock as it requires that a precise cut be made into the door’s edge and the box keep (the second half of a mortise lock’s mechanism) be installed in the doorjamb.

The installation of a mortise lock requires experience, precision, and specialized tools like a mortising jig.

Mortise Deadlock vs Mortise Sash Lock – What’s the Difference?

Many kinds of mortise locks exist today, but the two most commonly used ones are the mortise deadlock and mortise sash locks.

Mortise deadlocks offer the simplest kind of locking mechanics with just a keyhole and a locking bolt that goes in and out of the mortise locking mechanism. Mortise sash locks feature an extra latch mechanism, which is operated using a handle, allowing you to open and close the door without a key. However, internal doors featuring sash locks can still be locked using a key.

Other Types of Mortise Locks

  • Mortise Night Latches – This mortise lock automatically locks itself when the door is closed and requires a key to open the door from outside.
  • Mortise Electric Locks – Different electric lock mechanisms, including push buttons, key switches, intercom, and biometrics, can operate these mortise locks.

Why Should You Consider Installing a Mortise Lock for Improved Home Security?

Two prominent features offered by mortise locks are durability and dependable security.

Dependable Security

Mortise locks for the significant security that they offer regardless of the type. However, not every mortise lock offers the same level of security as the next. Some are more secure than others.

The more levels there are inside the mortise lock mechanism, the more secure it is. Typically, a three-lever mortise lock is more secure than a two-lever. The five-lever mortise lock and higher are commonly used in commercial buildings that require a higher level of security and breach protection.


If you need a lock that works well for the harsh usage conditions of commercial doors or entrance doors, mortise locks may be the right option for you. These locks hold up well when subjected to constant use and abuse and typically last a long time due to their internally mounted nature.

Mortise locks are typically made from copper, heavy-gauge steel, and reinforced aluminum.

Mortise Lock Brands to Consider

Depending on where you are situated, the mortise lock is a very common type of lock used by many for their homes and businesses. However, not all locks are created equally. Some mortise locks are of a higher quality than others. This is why we recommend shopping for your lock sets from verified and reputable lock brands.

Here are two brands we highly recommend you check out when shopping for your next set of door accessories:


The Schlage brand is perhaps one of the most well-known names in the lock and door accessories industry. The first Schlage patent was developed in 1909, and since then, the company has served millions of customers around the world with premium locks and door accessories. Schlage mortise locks are some of the best highly secured locks in the United States.

The popular Schlage slogan, “Didn’t invent the lock, they perfect it,” tells you all you have to know about the brand’s manufacturing standards.

Adams Rite

Adams Rite is a company with over 100 years of experience manufacturing aluminum-based hardware. It is safe to say you can trust the team at Adams Rite to provide you with mortise locks and other door accessories like bolts, pull latches, door hinges, door handles, and more that would last for a very long time.

Where to Buy Mortise Locks

The best way to ensure the absolute security of your building is by installing only genuine mortise locks from trusted manufacturers with decades of experience designing and developing high-level security locks with tons of extra features.

All Security Equipment is your one-stop shop for all things security-related. It doesn’t matter if your building requires special mortise locks with unique mortise lock functions or perhaps you double cylinder locks over the many variants of mortise lock sets that we offer. Our team has got you covered.

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