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Written by Rob Lancaster

Cylinder Locks – A Buyer’s Guide

With so many different types of locks out there, it can be difficult to know which is best for you. That’s why the team here at are putting together a series of handy guides all about our locks products to help you make the right decisions for your security needs. In the first of this series, we take a look at cylinder locks: what they are, what they’re for and how to fit them.  

What is a cylinder door lock? 

A cylinder lock (also sometimes referred to as a barrel) is a common sight in most properties nowadays, being a reliable option to offer security. A cylinder lock can be identified by the small thin keyhole, and the large flat surface of the cylinder. A cylinder lock usually takes a flat key and has all its locking components housed inside the cylinder. A cylinder lock is usually used in UPVC doors and offers good security for many homes whether new or old. Often referred to as a Euro cylinder lock, these locks are popular in many new builds and are often used to upgrade security on older build houses and properties. These door locks are easy to install, replace, and maintain so offer the perfect option for many properties. Door cylinder locks are also available with additional anti-burglary options like anti-snap and anti-bump (which will be discussed later in this guide).  

How to measure a cylinder lock 

It’s very important that your locks are measured and installed properly, to ensure that they are as resistant to break-in attempts as possible. A lock not fitted correctly becomes vulnerable to snapping techniques and is even more likely to suffer day to day wear and tear. It may also render your insurance policy void if your door locks are not properly fitted and compliant to home insurance policies. A cylinder lock must be flush to the door surface, or at least no more than 3mm away from it.  

Measuring and fitting a cylinder lock is a simple process that can be carried out by anyone with some basic tools and DIY skills. Although there are many different types of cylinder lock the fitting steps remain the same. There are 3 measurements that are taken to describe a cylinder lock’s dimensions. The cam, which is the moving part within the lock that carries out the locking process, is measured, along with the lock cylinder either side of it. This creates three measurements – cylinder, cam, cylinder. These two cylinders are often referred to as the A side and B side, where A is facing externally, and B is facing internally. Locks can be symmetrical and have the same cylinder lengths both side of the cam, or offset, or alternatively can even have only one cylinder (a single Euro lock).  

If you are measuring your lock and don’t want to remove it from the door, then the measuring process differs slightly. The lock is secured in the door by a central screw. Measurements need to be taken from the central screw to the outside of the lock. These two measurements should add up to the full length of the cylinder, including the cam.  


Where to use a cylinder lock 

Cylinder locks are often found in 

Cylinder locks are versatile and easy to install and replace when necessary, making them useful in a variety of situations.  

Types of cylinder locks 

As mentioned previously, there are many different types of cylinder locks. There are a variety of different Euro cylinder lock sizes to fit your doors, as well as options with thumb-turns, or single Euro cylinders. Security options include anti-bumping, anti-snapping, anti-drilling and anti-picking.  

How do I choose a Euro cylinder lock?  

There are many security options available on cylinder locks. A good way to decide if your potential lock is up to scratch is by checking if it is BSI approved. The British Standards Institution carry out many rigorous tests on locks, and can award them with up to 3 stars. Bristish standard locks are trusted throughout the country and are a good way of verifying a locks reliability. For a door to be considered maximum security it must have 3 stars in security features. This could include a 1 star lock and a 2 star security handle. Most insurance companies require British Standard locks to be eligible for their cover. These do not have to carry stars but must be either: 

There are a number of other features that a lock can have to provide extra security.  

British Standards Locks

Which is the best cylinder lock? 

Any lock rated 3 stars by BSI is the best lock you can buy. The ASEC Kite Elite cylinder lock offers 3 star protection, including all the anti-tampering measures listed above. The EVVA EPS 3 Star Snap Resistant Euro Double Cylinder is also another good high-security option for securing your property. Using the BSI system you can always be assured that your lock is up to the task of keeping any unwanted visitors out. It’s also worth noting that there are different numbers of pins available in locks. 6 pins offer more security than 5 as they are harder to manipulate. Additionally, you need to think about which is the best lock for your certain situation and whether you want a thumb-turn or not. 

Replacing a cylinder lock 

If you want to replace and upgrade your current cylinder lock, it’s extremely easy to do. The lock is held in place by the central screw discussed earlier in the measuring guide. Removing this screw allows the lock to be removed easily and replaced with your new upgraded one.  

Once the screw holding the lock in place has been removed, insert the key 

Turn the key to the left or right and pull on the lock. Here you are trying to align the cam so the lock can be removed.  

Once the cam is aligned the cylinder lock should slide out. To fit a new one follow these steps in reverse, and replace the screw in the side of the door to hold the lock in place.  

That concludes our complete guide to Euro cylinder locks. Now you should be equipped with the knowledge to check the standard of your current lock, measure it up, and if necessary, replace it. At Locks4 we offer a wide range of Euro cylinder locks, including the two high-security recommendations made above. From British Standard locks to more affordable, reliable security options, we’ve got you covered when it comes to securing your property.  

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About the author

Rob Lancaster is part of the marketing department at He researches and writes content for the site, producing guides, blogs, and articles.

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