While it might only be a few inches from end to end, the lock on your front door is arguably the most important security feature in your entire home.

Locks come in several varieties, each with its own strengths and weaknesses. One of the most readily available and secure types of lock is the mortice lock. These earned their name thanks to the pocket (or mortice) that the bolt slots into, which is cut into the internal face of the doorframe. When the bolt is in the mortice, the door is unable to move and is securely locked.

It’s important to understand how a mortice lock mechanism works before deciding whether you should have one for your external doors.

How do Mortice Locks Work?

A mortice lock relies on a relatively large mechanism, which slots into the interior of the door. This means that the door in question must be of a certain thickness, in order to accommodate the lock. For this reason, it is unlikely to find them installed on internal doors, and most prominently on entrance doors to your home.

Inside this mechanism is a space for the bolt to retreat into, as well as a series of parallel levers which are attached to the rear of the bolt via a small piece of metal called a bolt-stop.

The cut of the key is designed to match the levers on the interior of the matching lock. If the right key is used, then all of the levers align, and the whole mechanism can be rotated to withdraw and extend the bolt. If the wrong key is used, the key either won’t fit into the lock, or it won’t catch all of the levers in the right way.

A mortice lock will also incorporate several other components. These include the strike plate, and a piece of metal surrounding the mortice. This ensures that the bolt slots straight in, rather than scuffing against the surrounding wood.

There’s also the faceplate, which is often a separate piece of metal that attaches to the door, facing the strike plate. Finally, the escutcheon plates sit around the handle to preserve the look of the door. It serves no function beyond aesthetics.

What Type of Doors are Mortice Locks For?

Mortice locks are primarily found on external doors. They can, however, also be used on internal doors to control who has access to certain parts of the house. You might do this if, for example, you’re running a bed-and-breakfast, or you’d like to keep garage doors under lock and key for security reasons.

For most homes, however, you may need to install entirely new doors that can accommodate the sheer size of a mortice lock.

What’s the Difference Between a Mortice Dead lock and a Mortice Sash lock?

Mortice locks come in a few different varieties, the most common being dead locks and sash locks.

Mortice deadlocks are the simplest. They only have a keyhole and a locking bolt that goes back and forth.

A mortice sashlock, on the other hand, features a handle-operated latch mechanism. This means you can open and close the door without having to use the key, but can still lock the door when you leave the building.

Are Mortice Locks Secure?

Mortice locks are popular for a good reason – they offer excellent security and reliability. But some mortice locks are more secure than others. The more levers there are inside the mechanism, the more difficult the lock will be to pick. Those with five levers or more are generally considered to be the standard mortice lock for external doors. Three-lever locks are cheaper to produce and buy, making them a good choice for internal doors.

You can also buy seven-lever mortice locks, which are somewhat more secure than five-lever mortice locks.

The main thing to look for is a mortice lock that’s compliant with the BS3621 standard or above. This certifies that the lock is sturdy enough that it can’t be dismantled from the outside. Specifically, it should last for five minutes when a tester tries to drill or cut through the bolt, and the bolt will need to extend two centimetres into the mortice. Another thing to look for is the British Standard kitemark, which is the industry’s mark of quality.

The Metropolitan Police recommend combining a mortice deadlock with a double-locking night latch, so you have some redundancy when it comes to security. That way, if one device fails, you’ll have another to fall back on. Other police services offer similar advice.

Rear and patio doors are often targeted by thieves, as the intruder doesn’t have to try and gain entry in view of the street. These sorts of doors are generally supplied as a single unit that can’t be modified with additional locks. Modern patio doors are far more substantial than those of yesteryear, so if this is a concern, you might want to upgrade your Frenchsliding, or bi-fold doors.

What are Rim Locks?

Compared to mortice locks, rim locks attach to the outside of the door and latch against the outside of the door frame, as opposed to internally.

Rim locks can be used as an additional lock to mortice locks, as they are a less secure locking mechanism. Rim locks can be found on older front doors that do not feature mortice locks and are used to support the security of the door.

So, Should You Buy a Mortice Lock?

As far as door locks go, mortice locks are some of the most popular door lock types on the market. With an ever-increasing amount of door furniture readily available from most door retailers, there is no struggle in decorating your door with a new multipoint lock.

A mortice lock is a standard across the country, thanks to a robust and resilient design that’s stood the test of time. While the internal mechanisms will be of interest to engineers, most of us only think about our mortice locks when they stop working. Invest in one that’s of the required standard, however, and this is unlikely to happen!

Posted on: 24 September 2019

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