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Lock Blog

A resource for consumers, locksmiths, and security professionals

3 Easy Steps For Mortise Lock Replacement

by Wesley March 23, 2022

Making sure every door in your home has a secure lock is critical to the safety and well-being of everyone. It is your responsibility to keep up with the maintenance and working conditions of your locks over time. And a big part of that is knowing when mortise lock replacement is necessary.

You might be thinking to yourself, what is a mortise lock? As a popular lock type, you have probably used a mortise door lock handle thousands of times throughout your life. You may have even picked one out in a catalog or at a home improvement retail store.

The purpose of this article is to get you familiar with mortise locks so that when it is time for a mortise lock replacement, you will know exactly what to do. Mortise lock replacement is simple, and when you follow these three easy steps:

  1. Assess Existing Lock
  2. Replacement Benefits
  3. Hire A Locksmith 

Before we get into the details of mortise lock replacement and the lock installment process, there are a few basic materials we need to cover. Certain terminology can get confusing, so let us first go over some mortise lock concepts.


What is a mortise lock?

Although you may not know it by name, chances are you have both seen and used a mortise lock countless times. As we said in the beginning, mortise locks are one of the most popular residential door lock types. They can be found in homes, businesses, stores, warehouses, and every other space that has doors.

Mortise locks typically have a uniquely shaped door handle that connects to its internal locking mechanism. In fact, the door handle is probably what most people would consider as the mortise lock’s defining quality. This door lock hardware has been around since the 18th century and has made its way into the modern marketplace.

We will get into more specifics later about the exact parts of mortise locks, but essentially they use a rectangular lock body that fits into a pocket. These lock bodies are quite complex, with multiple moving parts inside of them that work together to lock the door. That is why knowing exactly what you are doing is vitally important to mortise lock replacement.  

Are mortise locks universal?

In general, mortise locks are versatile pieces of hardware. Most often used as commercial locks but sometimes appear on homes or as apartment door locks. You can find mortise locks on both the back and front doors as well as on interior doors that lead to bedrooms, bathrooms, and basements. 

For commercial use, mortise locks work well on office doors, public restrooms, and workshop entryways. Keep in mind there is no limit on the number of mortise locks you can install. But for a better understanding of where to place them, a certified locksmith can offer expert advice and properly perform mortise lock replacement.

Are all mortise locks the same size? 

Mortise locks typically come in two different sizes, 2 ½ inches and 3 inches, which is what can make mortise lock replacement a simple process. The measurements are based on how far the keyhole is from the edge of the door.

Only having to worry about two different size options is nice, but you have to determine which size your door will need. It is not as simple as how big your door frame is. There are a bunch of factors like which parts you need (We will touch on this part later). This is something a professional locksmith can help you with when undergoing mortise lock replacement.

Is a mortise lock more secure than other locks?

On the security scale of door locks, mortise locks rank toward the top for their strength and reliability. Now, it also depends on what kind of application you are seeking. Companies would never use a mortise lock on something like a bank vault because that is not what they are meant for.

Mortise locks are manufactured specifically for commercial and residential uses, and they are very effective in both arenas. Any locksmith or security expert will tell you the complexity of its internal locking mechanism makes a mortise lock fully capable of securing your home or business.

1.  Assess Existing Lock

The first step in understanding mortise lock replacement is figuring out what kind of lock your doors currently have. If you already have mortise locks installed, then replacement procedures will be much more simple. However, changing from a different door lock type will require a little more effort and craftiness.

There are six common types of residential door locks that you will not only find in homes but across offices and commercial spaces everywhere. Mortise locks are one of those six types, which means there are multiple approaches to mortise lock replacement. Let us start with replacing an existing mortise lock.  

Familiarizing yourself with the different parts of a mortise lock for basic knowledge purposes is important before you open any toolbox or pick up the phone to call a locksmith. Components of a mortise lock have solid metal construction, large springs, and are built out of hardy materials for optimal function.

Mortises are a combination of many different pieces that must be placed into a pocket in the door. Perfect mortise lock replacement assembles the pieces around the pocket. The parts of the lock are:

  • Lock Body: The housing for the bolt work, which are the components that will disengage and engage the lock.
  • Handle/Knobs: Turn in order to retract the latch once the door is unlocked.
  • Through Spindle: A long rod that connects the handles/knobs through the door and mortise lock body.
  • Lock Cylinder: A threaded cylinder that will secure through the door into the lock body so that when a key is inserted the door will unlock. A mortise lock cylinder will have a cam, which is a rotating rectangular piece of metal that manipulates the handle’s ability to retract the latch.
  • Strike Plate: Metal fixture fastened onto the doorway to line up with the latch bolt and potential deadbolt that reside in the lock body of the mortise.

Complexity is a word that you will continue to hear throughout this article because not all mortise locks are the same. This is where knowing what parts you need comes into play. We discussed earlier the two standard sizes of mortise locks, but that does not include the variation of parts. Some mortise locks contain these additional parts:

  • Escutcheon/Rose Plates: These fasten on either side of the door to create cohesion around the lock cylinder and handle. 
  • Hard Collars: A metal protective ring that spins on the lock cylinder. The spinning movement prevents someone from prying out the cylinder with a tool.
  • Faceplate: Covers the internal housing of the lock system. Sometimes this is pre-fitted to the lock body. 
  • Day/Night Switch: Switch that locks the door from the outside and keeps it unlocked on the inside. It can also keep the door unlocked on both sides. 

Now that we know the different parts and their functions, the mortise lock replacement process can begin. For an existing mortise lock, there will be minimal adjustments made on the door itself because the pocket is already cut for the lock hardware. You are essentially just updating the lock with a new one. 

Mortise lock replacement is more complicated with different door lock types because it requires a full replacement of hardware and additional modifications to the door. Much like construction projects can gut entire rooms and hallways during a renovation, mortise lock replacement can be like this on a smaller scale.

Weight Benefits Of Mortise Lock Replacement

After an extended period of commercial or home use, either full mortise lock replacement will be necessary, or replacement of individual parts. For homes, deterioration occurs over several years before it begins to affect the lock’s usability. 

Cases of severe weather or rusted parts will weaken the lock further, making it less secure. Severe damage can require an immediate mortise lock replacement.

Most mortise locks found in old homes are original to the house, and because of the lock’s longevity, they can continue to function for decades. This is a major reason why people prefer mortise locks to other types.

Mortise locks have been considered antiques or relics from another era, which people place a great amount of value on. That is why proper maintenance is critical, and expertise must be used when deciding on what to do with antique locks.

One of the main benefits of mortise lock replacement is it offers one of the simplest door lock cylinder replacement processes around. Because these locks are designed for commercial and residential settings, the hardware is designed to be more firm than the keyed cylinder.

Instead of a full commercial door lock replacement, you can quickly remove and replace just the keyed cylinder. The lock cylinder can be removed and changed without removing the lock body from the door.

By placing the lock body in a rectangular pocket cut into the door, the cylinder is secured to the hardware with a set screw. This set screw is accessible when the door is open, and as long as you can open your door, the cylinder replacement is fast and easy!

The parts for each model and brand will vary slightly, but the design of the mortise is meant to withstand extended use over time. The internal mechanisms are also designed to be easily replaceable and serviceable, which comes in handy for anyone who needs a mortise lock replacement.

 3. Hire A Locksmith 

Anyone can attempt mortise lock replacement themselves with tools and a few online tips. But to guarantee it is done right, calling a locksmith is the best solution. With several years of experience in the locksmith industry, these technicians know exactly how to treat mortise locks with care.

Because these locks are often antiques, it is very important to know how to service them and find out if they have issues. Sometimes they are found in older homes with quite a bit of rust, which means someone conducting proper antique mortise lock replacement needs to remove the rust, clean the bolt work, and polish the metal.

In some cases, older parts may not be salvageable and could present security vulnerabilities for your door. Your safety should always be prioritized over everything else when dealing with door locks, and locksmiths understand this principle exceptionally well.

As you have learned throughout this article, mortise lock replacement can get very technical. Aside from the varying moving parts in each lock, you also need someone who recognizes when individual parts are malfunctioning. A locksmith might be able to save you from getting a full mortise lock replacement and only replace a single part to fix the problem.

Another key topic in mortise lock replacement is lock lubrication. In several instances, when you are dealing with older hardware, rust is not your only issue. The accumulation of dirt and grime over the years causes problematic buildup and blockage to the locking system. Going into the garage to find your generic lubricants is not the answer.

Spraying any lubricant into the locking mechanism goes against every professional’s recommended advice. Using the wrong lubricant can further the problem and potentially cause damage to the door lock. That is why locksmiths take a calculated approach to every door lock to ensure the best methods are used, especially when elevating your security with a mortise lock replacement.

Closing Advice

Mortise locks are revered for their design and uniqueness and how they bring a certain sense of flair to any home or office. But beyond adding a chic look, they are effective at providing security. Doors with mortise locks are successful in keeping unwanted visitors from entering a room, which is why proper mortise lock replacement is paramount.

Trusted security industry experts are available to offer their advice and services for your mortise lock replacement at your convenience and on your schedule. They are called locksmiths, and with their trained hands and craftsmanship, you can expect quality results for mortise lock replacement every time.

Category: Lock Types, Safety & Security

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