What Is a Rim Lock?
A rim lock is a traditional lock fitted to the surface of a door rather than recessed into the door itself. The lock body appears as a box on one face of the door and closes into a keeper fitted to the door frame. Depending on the model, it can operate as a simple latch or be locked with a traditional skeleton key.
Rim locks are one of the most recognisable types of heritage door hardware. Today, reproduction rim locks are mainly used on internal doors where their visible, traditional appearance is part of the room's character.
✔ Escutcheons included with some models
✔ Traditional skeleton keys included
✔ Face-fixing screws and keeper included
How does a rim lock work?
The lock body is fixed to the surface of the door. When the door closes, the latch enters a separate keeper mounted on the door frame. Turning the door knob moves the latch so the door can open.
On a lockable rim lock, the skeleton key operates a separate locking bolt. This allows the door to be locked or unlocked from either side, provided a key has not been left in the keyhole on the opposite side.
Because the mechanism sits on the face of the door, a rim lock is clearly visible from one side. From the other side, you will normally see the door knob with backplate and a keyhole escutcheon rather than the lock body.
The history of rim locks
One of the oldest lock designs, the rim lock is an important piece of restoration door hardware when refurbishing a heritage home. Early versions used a simple lever and bolt. As the design developed, lockable models operated by the now iconic skeleton key became common.
Rim locks were widely used in England and Ireland and are still found in many traditional homes there for low security applications. They were also used throughout Australia, particularly on doors that were not thick enough, or were not constructed in a way that suited a recessed lock.
In Australia, they are often associated with cottages, farmhouses and other heritage homes. They were commonly fitted to ledge and brace doors made from vertical timber boards, with horizontal ledges and a diagonal brace forming a “Z” shape on the back.
What is the difference between a rim lock and a mortice lock?
The main difference is where the lock body is installed.
A rim lock is mounted on the surface of the door, so the lock body remains visible on one side. A mortice lock is recessed into a pocket cut into the edge of the door, leaving only the faceplate visible when the door is open.
Which door knobs work with a rim lock?
Our rim locks are designed to be used with mortice knobs. These are traditional round door knobs normally supplied as a pair with two detachable backplates and a threaded spindle. Any of our mortice knobs can be used with a rim lock; “rim lock door knob” is simply another name commonly used for this application.
Despite the name, a mortice knob does not always require a mortice lock. The same style of knob can work with a compatible rim lock, tubular latch or mortice lock.
For a rim lock installation, the knob on the lock side fits directly against the rim lock body, so the backplate on that side is removed. The other backplate is fitted to the opposite face of the door to provide a neat, finished appearance.
The threaded spindle passes through the door and the square spindle hole in the rim lock. The knobs screw onto the spindle, are fixed to the spindle using grub screws, connecting both sides and allowing either knob to operate the latch. This also gives the knobs more support, rather than relying only on the face fixing screws in the backplate only.
Mortice knob spindles are intentionally supplied long so they can suit different door thicknesses and installation types. The spindle can be cut down on site if required. Standard modern knob sets with a different fixing arrangement are not necessarily suitable.
What parts do I need for a rim lock installation?
A typical rim lock setup requires:
- the rim lock body
- a compatible keeper for the door frame
- face fixing screws
- one or more skeleton keys for a lockable model
- a compatible pair of mortice knobs with a threaded spindle
- an escutcheon for the keyhole on the opposite side of the door.
The lock, keeper, screws and keys are supplied with our lockable rim locks. Some models also include an escutcheon. If your chosen lock does not include one, you can select a suitable design from our escutcheon collection.
Always check the individual product description before ordering, as inclusions and dimensions can vary between models.
What is an escutcheon?
An escutcheon is the small plate fitted around a keyhole. It protects the door surface from marks caused by the key and gives the keyhole a more finished appearance.
The rim lock body already surrounds the keyhole on the lock side of the door. The escutcheon is therefore normally installed on the opposite face, where the key passes through the door to reach the lock.
Can a rim lock be fitted to any door?
Rim locks suit many solid timber internal doors, particularly traditional doors and ledge and brace designs. However, they are not suitable for every door.
Before choosing a lock, check:
- Door construction: There must be enough solid material to secure the lock and knob fittings properly.
- Door thickness: Confirm that the spindle and fixings will suit the thickness of the door.
- Door direction and handing: Rim lock handing varies between models. Some are supplied in a specific left or right handed configuration, while selected models can be reversed by turning the complete lock over. “Reversible” refers only to changing between left and right hand operation; it does not mean the lock is universal or can be installed on either face of the door. Always check the handing and installation requirements listed on the individual product page. Do not pull the lock apart to reverse the latch tongue, as this may cause the lock to stick and could void the warranty.
- Door frame and keeper position: There must be a suitable flat surface on the frame for the keeper to align correctly with the latch and locking bolt.
- Existing holes and hardware: Check whether the new lock, knob backplate and escutcheon will cover any previous cut-outs, fixing holes or marks.
- Clearance: Make sure the lock body, knobs and keeper will not interfere with mouldings or architraves.
If you are replacing an existing rim lock, do not choose a new one by its overall appearance alone. Compare the lock body dimensions, spindle position, keyhole position, projection and keeper arrangement. Reproduction locks are not guaranteed to match the fixing holes or preparation of an older lock.
Are rim locks secure?
Reproduction rim locks are considered low security locks by modern standards. We recommend them for internal doors and other low security applications where traditional appearance is the main priority. They are not generally suitable as the only lock on an external entrance door.
For a front or external door, choose a modern entrance lock or deadbolt that provides the required level of security. A rim lock may sometimes be added as a decorative or secondary feature, but it should not be relied on as the main security lock.
Can I use a rim lock on a bathroom or toilet door?
A lockable rim lock can provide privacy, but our reproduction rim locks do not have an emergency release. This means they are not normally our first recommendation for bathrooms, toilets or other rooms where someone may need to gain access quickly from outside.
If a rim lock is used on an internal room, keep the spare key in a known and easily accessible place. Do not leave a key inserted on the other side of the lock, as this can prevent a second key from operating it from the opposite side.
It can also be helpful for internal doors to use lift-off hinges or loose-pin hinges, where suitable. These may provide another way to gain access without unscrewing fixed hinges, although this will depend on the door, its opening direction and whether the hinge pins are accessible.
For a bathroom or toilet, a privacy latch or privacy lock with an emergency release is generally the more practical choice.
Choosing a reproduction rim lock
Start by checking the door, frame and direction of opening. Then compare the dimensions of the rim lock itself. Once you have selected the lock, choose your mortice knobs and confirm whether an escutcheon is included or needs to be ordered separately.
If you are unsure which parts work together, contact us with links to the products you are considering, along with your door thickness, direction of opening and clear photos of both sides of the door. We help customers check these combinations every week and can confirm whether anything else is required before you order.
Rim lock FAQs
Why is it called a rim lock?
It is called a rim lock because the lock is mounted on the surface, or rim, of the door rather than installed inside a mortice cut into the door edge.
Does a rim lock need a special door knob?
It needs a mortice knob, also commonly called a rim lock door knob, with a threaded square spindle. A standard modern knob set may not fit correctly because they are usually attached to their backplates.
Do I use both knob backplates with a rim lock?
No. The knob on the lock side normally fits directly against the rim lock body. One backplate is removed, while the other is used on the opposite face of the door.
Does a rim lock come with a keeper and keys?
Our lockable Tradco rim locks include the keeper, face fixing screws and traditional skeleton keys. Some models also include an escutcheon. Check the individual product page for the exact inclusions.
Can I replace an old rim lock with a reproduction model?
Often, but it may not be a direct fit. Compare all dimensions carefully, including the spindle and keyhole positions, and allow for possible new fixing holes or adjustments to the keeper.
Can a rim lock be used on an external door?
It may physically fit some external doors, but a reproduction rim lock is a low security product and should not be used as the main security lock on an entrance door.
