Last updated: October 15, 2021

Welcome to our big box lock test 2021. Here we present you with all the rim locks we have tested in detail. We have compiled detailed background information and added a summary of customer reviews on the web.

We would like to make your purchase decision easier and help you find the best rim lock for you.

You will also find answers to frequently asked questions in our guide. If available, we also offer interesting test videos. Furthermore, you will also find some important information on this page that you should definitely pay attention to if you want to buy a rim lock.


  • Rim locks are very easy to install and inexpensive to purchase.
  • The flexible use on many doors is the advantage over conventional mortise locks.
  • Additional box locks and box locks for theft protection also increase security.

The Best Box Lock: Our Picks

Guide: Questions you should ask yourself before buying a Box Lock

What is a box lock?

Rim locks are a form of screw-on lock. On the visible front, there is only the keyhole and the follower for the handle. The locking mechanism is covered by a box.

The box lock is also called a surface-mounted lock. It is usually fitted on the inside of house or flat doors. The same applies to furniture and chests.

Nowadays, the rim lock for flat doors has largely been replaced by the mortise lock.

Compared to mortise locks, however, rim locks have the advantage that they only require 2 holes for mounting the rim lock. Furthermore, rim locks are mainly used for doors where mortise locks cannot be installed due to their thinness.

What are the uses of a box lock?

Box locks are not only available in the form of screw-on locks for flat or house doors. There are also additional box locks that are attached to the inside of the door to additionally increase security.

In addition, there are box locks as anti-theft devices for car trailers

But the main places where box locks are used are wooden doors, such as a garden gate, cellar door or summerhouse.

How do I determine the required dimensions?

Since the rim lock is only screwed on and not inserted, you only need a few dimensions compared to a mortise lock.

The most important measurements you need are:

  • The backset: This is determined by measuring the length from the outer edge of the faceplate to the centre of the keyhole.
  • The distance measurement: This measurement is standardised in Germany and has a length of either 72 mm, 78 mm or 92 mm. It is measured from the centre of the cylinder recess to the centre of the square.
  • Square dimension: The dimensions of the square recess can also be important for installing matching lever handles.
  • Dimensions of the box: The dimensions of the box do not have the same importance as with a mortise lock. Since the box lock is screwed on, it is not necessary to measure it to the millimetre. Nevertheless, the dimensions are interesting for the visual impression.

How do I install a box lock?

You should not worry about the installation of box locks. The great advantage of this type of lock is that it is so easy to install.

How to install the lock will become clear when you stand in front of the door with the lock.

What alternatives are there to a box lock?

The only alternative for flat doors that is still mostly used today is mortise locks. Mortise locks have a higher security standard because they are inserted into the door.

Mortise locks are available in many different versions for flat doors. In addition, electronic mortise locks are becoming increasingly popular.

Mortise locks are also available for garden arbours or garden gates. However, box locks are more popular for this use because they are easier to install and security is not a top priority there.

What Types of Box Locks are there and which one is right for you?

What are the characteristics of a screw-on box lock and what are its advantages and disadvantages?

A box lock or screw-on lock only competes with a mortise lock.

The rim lock is characterised by its simple installation and its universal application possibilities. The rim lock only requires 2 recesses, which can also be added yourself, making it ideal for wooden doors.

The only disadvantage compared to mortise locks is the lower security level. Because box locks are screwed on the outside, they are easier to manipulate.

  • Easy to install
  • High flexibility
  • Cost effective
  • Lower security level than mortise locks

What are the characteristics of an anti-theft box lock and what are its advantages and disadvantages?

An anti-theft box lock is used to secure car trailers. If you park your trailer in a public area, you should secure it so that no one can simply pull it away.

This box lock makes theft much more difficult. There are no arguments against this additional security, especially as it is very cheap to buy and you can park the trailer with greater peace of mind.

  • Cost-effective
  • Increased security
  • Increased feeling of security
  • [Keine] x1
  • x2
  • xn

What are the characteristics of an additional box lock and what are its advantages and disadvantages?

An additional box lock is attached to the inside of your house or flat door. By turning a knob, this additional lock is locked from the inside. The lock can be locked from the outside with a key.

Such an additional lock increases security enormously. Burglars have to act quickly. Since they have to manipulate not only one lock, but two, they lose a lot of time and are more likely to refrain from unauthorised entry.

  • Cost-effective
  • Increased security
  • Increased sense of security
  • Nothing

Buying Criteria: These are the Factors you can use to compare and evaluate Box Locks

There are various criteria you can use to compare and evaluate rim locks. The following criteria are important when buying a rim lock:

Need for security

The higher the value of what is behind the secured door, the higher your security needs. If you are only securing a few garden tools, you do not need the highest quality.

However, if you are securing your cellar door, where some belongings are stored, you should look for high quality workmanship and a high level of security.

Opening direction

Doors can open inwards or outwards and to the right or left.

Make sure the lock you buy is suitable for the direction you need it to open. There are many universal box locks that are suitable for all opening directions.


The dimensions of your door are, of course, the limiting factor as to whether the box lock will fit or not. If your wooden door does not yet have any recesses, then you do not have to worry about the dimensions not fitting, because you will be making them.

I have explained which measurements are important and how to determine them in the guide section.

Type of trap

A distinction can be made between a lifting and a closing latch. Many rim locks usually have lifting latches. The advantage of closing latches is that by simply pulling the door shut without locking it, it is still not possible to gain access by simply pressing the handle.