Euro profile cylinder: DIN EN 1303 / DIN 18252

The euro profile cylinder is the standard locking part in flat doors. Its measurements and resistance classes explain why standard cases have fixed prices – and when a separate fixed price is needed.

Length to the outside and to the inside, measured from the centre of the fixing screw (DIN 18252). In flats often 30/30 to 35/40 mm, in 5 mm steps. The wrong size means the cylinder sticks out or is too short – a risk to both security and function.

The 8th digit of the marking shows the class: 0 / A–D (or 1–2 under the older system). Tests include drilling and pulling out the core (pulling forces of, for example, 10–15 kN for the higher classes). Police guidance: drill protection is a must; A is better than B without pull protection, C is better than D with pull protection. Class 0 is considered unsuitable for burglary protection.

An additional approval (A / AZ / B / BZ / BZ+) alongside DIN, issued by VdS, the German insurers’ testing body – often required by insurers or for higher demands. BZ = medium protection with built-in pull protection. Not required for every standard flat; the extra cost is fixed before fitting.

Many cylinders have markings stamped on the side or on the end face. They show the manufacturer, the standard and the protection class. What matters for you: if there is a mention of drill protection and pull protection, the cylinder is better protected against burglary. If there is no such mention, it is usually a simple standard cylinder.

For a flat door in a block of flats, a good standard cylinder is often enough if there is a security door plate. For front doors, ground-floor doors or doors without a security door plate, we recommend a cylinder with drill protection and pull protection. For a cellar or garden shed a simple cylinder is usually enough.

With this function the door can be opened from outside even when a key is in the lock on the inside. This is handy for families with children and for older people who live alone. From the outside the cylinder looks like any other.

Cylinders can be made so that one key fits the front door, flat door and cellar. This is called keyed alike. It saves keys on your key ring, but has to be ordered in advance.

Many security cylinders come with a card. New keys can only be ordered with it. Keep the card separate from the keys, for example with your documents.

If your cylinder is more than twenty years old, stiff or has no visible protection, a new one is worth it. A change also makes sense after you move in, because you never know who else has a key. With the door open the change costs 89 € Monday to Friday from 8 am to 6 pm, at other times 119 €, with a standard cylinder.

The principle of using pins is very old. As far back as ancient Egypt there were wooden locks in which a key lifted small pins so that a bolt could be moved. Today’s metal cylinder was developed in the 19th century. Since then it has been made with ever greater precision. The shape you see on almost every flat door in Germany is standardised, so that cylinders from different manufacturers fit into the same locks.

Inside the housing sits a core that can turn. Several holes run through the housing and the core, each with a pair of pins and a small spring above them. Without the key, the pins block the core. The right key lifts each pair exactly far enough for the gap between the pins to lie at the edge of the core. Then the core turns, and in the middle the cam moves the lock. A wrong key lifts at least one pair too high or not high enough.

Look at the cylinder from the side: it is round at the top and has a narrow web at the bottom. This cross-sectional shape is the profile that gives the euro profile cylinder its name. In the middle of the web there is a hole for the long screw that holds the cylinder in the lock. This is exactly where the cylinder is weakest. That is why it should hardly stick out on the outside.

A cylinder needs very little care. Once or twice a year, give the keyway a short spray of lock spray, then turn the key a few times and wipe it clean. Nothing more is needed. Too much grease or oil attracts dust and makes the cylinder stiff over time. Follow the manufacturer’s instructions, as some cylinders need a specific product. Graphite or spray, but never cooking oil.

A cylinder on the front door of a house is exposed to rain, frost and dust. It should therefore be robust and be looked after a little more often. If rust appears on the front face, or the key is stiff in winter, that is a warning sign. A cylinder on a flat door in the stairwell has an easier life and often lasts for many years. For basement doors on a damp lower floor, it is worth checking now and then for rust and corrosion.