Components & reference points

Half-cylinder of the lock

A half-cylinder has a single key entry. It allows commanding a mechanism from one side, particularly on certain garages, technical rooms, barriers, or keyed contactors.

DEFINITION · HOW IT WORKS · ADVICE

Half-cylinder lock — illustration from the MULTISECU glossary

THE KEY POINT TO REMEMBER

A single keyway does not mean the door cannot be opened from the other side: it depends on the lock and its internal mechanism.

What sets it apart from a double cylinder

A double cylinder has two keyways. A button cylinder has one keyway and one internal actuator. A half-cylinder only takes one side of the actuation in a shorter configuration.

It is selected when the mechanism does not require a second key side. There are also half-cylinder button configurations for specific applications.

Diverse applications

It is found on some garage doors, cabinets, and control devices. In a key actuator, it does not necessarily directly lock a door: it may allow an electrical action.

The intended use determines the required function, particularly the key retraction position and the type of drive. Two products with the same profile can meet different needs.

Length and cam

The useful length must be measured from the intended mounting reference and the cylinder profile must be verified. The length must match the mechanism and its external protection.

Some models feature an indexable cam whose initial position can be adjusted. The angle, shape, and compatibility with the commanded device must be confirmed prior to purchase.

Security, installation and maintenance

An external door requires appropriate cylinder protection and correct mounting. The selection also takes into account the required keys and the conditions for double entry.

Avoid forcing if the mechanism sticks. A check of the assembly, the cam, and the commanded device allows differentiation between a cylinder fault and a system-wide issue. Use only the recommended maintenance for the model.

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