Door Lock Defective – Tips for Purchase and Maintenance
Today we want to address the topic of door locks, also known as door closures. Besides possible reasons for a door lock defect, we would like to provide you with some tips for replacement. If we want to replace our defective door lock, we need to pay attention to several points during the purchase.
Types of Door Locks
Let's start with the different locking types of door locks and the various designs of door locks.
Locking Types
Locking type refers to the way we can lock the door lock. In some cases, these types are also referred to as "notching." We basically distinguish between three types, which are primarily found in the mortise lock area:
- Profile Cylinder (short PZ): The door locks are locked by a profile cylinder including a key. We often find these door locks in front doors, apartment doors, and garden areas.
- Ward Lock (short BB): Ward locks are considered the most commonly used door locks in the private interior door area. They have the classic keyhole to look through.
- Bathroom/WC: These door locks have the square fitting for attaching a turn handle, as we know from public toilets. The turn handles are usually delivered with a red and white color indicator to show if the toilet is free.
Mortise Lock
We often use a mortise lock in the interior and apartment door area. It consists only of the central lock case, which is operated by one of the above-mentioned locking types and a door handle. This lock is installed in a milled recess in the door leaf.
Multi-Point Locking System
Multi-point locking systems consist of a strip with three locking points. We secure our door at the top, middle, and bottom against unwanted visitors. These door closures are usually found in the front door area. Due to the mentioned area of use, only profile cylinders are used as the locking type here. Due to the complex design, it is necessary to pay attention to the manufacturer. Well-known manufacturers include Gretsch-Unitas and KFV.
Tip: When purchasing multi-point locking systems, we must ensure that the upper and lower locking types match the defective door lock.
Taking the Correct Measurements
We have now determined the type of defective door lock and the locking type. Now we need to determine the correct measurements, which are important for purchasing the right door lock.
Basic Measurements
We need the basic measurements for all types of door locks, i.e., for mortise locks and multi-point locking systems.
- Faceplate Width: The faceplate on a door lock is the visible strip that is screwed into the door leaf. We need the width of this faceplate to securely mount the door lock later.
- Faceplate Length: The length of the visible strip is called the faceplate length.
- Distance: We measure from the center of the square hole, where the handle is mounted, to the center of the profile cylinder hole.
Tip: In Germany, we often have a distance of 92mm in the exterior door area and 72mm in the interior door area. - Square Spindle Size: There are different thicknesses of square spindles for a door handle. This size must match the fitting in the door lock.
Tip: In Germany, an 8mm spindle is commonly used in the interior door area, and a 10mm spindle in the front door area. The intermediate size of 9mm is for panic and fire doors.
Extended Measurements for Multi-Point Locking Systems
In addition to the measurements already determined above, we need additional measurements for multi-point locking systems. Primarily, these are the distances from the center of the square to the center of the lower lock case (also called the B-measurement) and to the center of the upper lock case (also called the C-measurement).
Conclusion and Golden Tips
Summarizing this complex topic, we realize that it is important to take the correct measurements. If a measurement does not fit, it can lead to an annoying wrong purchase, and let's be honest, the defect of the door lock is annoying enough.
However, if we maintain our door lock properly, it can prevent a defect. Annual use of maintenance sprays is suitable for this.
Usually, in multi-point locking systems, the main lock case or the upper and lower locking points are broken. Therefore, we recommend looking for repair kits before purchasing a complete lock. These kits often save your wallet, nerves, and time.