SMR Locksmiths Ltd - Norbury and Streatham local locksmiths
South West London despatch point: 10 Cranbourne Close, Norbury, London, SW16 4NG

July 27, 2023

What is a Rim Lock?

A Rim lock differs from the usual type of mortice lock used on a front door which is internally mounted within the frame of a door.

A rim lock is not usually used on a front door as it is not as secure as a mortice lock unless supported by additional security devices such as bolts.

A rim lock is a type of door lock that is commonly used in residential settings. It is relatively simple and easy to install, making it popular for non-professional or DIY (do-it-yourself) installations.

Usually, a rim lock is held on by four screws and it’s kept by two screws; hence all it takes is a screwdriver to remove the lock internally and open the door.

Rim locks originate from the time that many doors were around 1 inch thick and could not accommodate mortice locks. Today most doors are usually 1.5-2 inches thick and so can accommodate internally fitted mortice locks.

As a security system, rim locks provide the most basic of security. A common make of rim lock will have no more than 15 to 20 different keys.

They are usually fitted for aesthetic and decorative reasons. A rim lock is externally mounted on the door hence it is on display. It is commonly used in a bathroom or other internal doors in a house, which is not to say that it cannot be used on the main entrances with additional security.

The benefit of a rim lock is that as it is externally mounted, there is no need to do complex woodwork or damage a door when fitting them.

A rim lock is typically mounted on the surface of the door, on the side that faces the interior of the room. It consists of a rectangular or cylindrical metal casing with a latch and a key-operated mechanism.

Rim locks also look fitting on period houses and can actually add to the interior decoration rather than detract from it.

rim lock feature image

There are two main types of rim locks.

Rim sash locks have a latch and will often also require a handle or a thumb turn to retract the latch – sometimes these come as part of the rim lock.

rim shashlock fluted

The latch is a spring-loaded bolt that extends from the lock casing and engages with the strike plate on the door frame to keep the door closed. When the door is closed, the latch automatically snaps into the strike plate, securing the door shut. To open the door from the inside, you can usually turn a knob or thumb turn to retract the latch.

On the exterior side of the lock, there is a key cylinder that allows you to lock or unlock the door from the outside using a key. This is useful for securing the door when you leave the house or need additional security.

Rim deadlocks just have a bolt and do not require a handle. Most rim locks are operated by a set of knobs which have either been made as a rim set or can be fitted as a rim set. One knob will have a backing rose for the non-lockable side of the door and the other knob will not have a rose for fitting to the lock side.

There are many attractive rim locks available for sale that can aid decoration and furnish a door, in the same way as an attractive and decorative door handle. You will also probably wish to use a matching escutcheon to cover the keyhole in the door.

Rim locks are available in many different materials including cast iron, brass, bronze and even wood.

Some very old rim locks would have been made from wood and have been large in size with a large key, not practical for keeping on a modern key ring. Reproductions of these locks are available from specialist ironmongers. This style of rim lock would suit an older style wood-framed Tudor house. Brass and black rim locks work well on Victorian or Edwardian houses, especially on bathrooms.

Some rim locks may have additional features, such as a privacy function that allows you to lock the door from the inside using a thumb turn, preventing anyone from using a key from the outside.

Some, are in fact designed particularly for bathrooms and even include an indication of whether the room is occupied. A much more refined way of finding out whether there is somebody in the toilet than attempting to open the door.

It’s worth noting that while rim locks are relatively easy to install, some basic DIY skills and tools are required. If you’re unsure about installing a lock yourself, it’s always a good idea to seek the assistance of a professional locksmith to ensure proper installation and functionality.

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