Types of locks
The mortice lock
The mortise lock takes its name from the mortise: the recess that receives its cabinet in the door. This inset installation requires precise dimensions to ensure proper operation of the window frame.
THE KEY POINT TO REMEMBER
The lock case, faceplate, and associated components must all match the new lock.
Mortice, lardered, in-built: the same principle
These terms refer to a lock whose body is integrated into the door's thickness. Only part of the equipment remains visible, notably the faceplate on the edge and door furniture on the faces.
The designation indicates how the mechanism is installed. It does not specify whether the lock is a single-point, multi-point, or certified against forced entry.
The role of the mortice
The lock case must fit into the housing without compression or excessive play. Fasteners hold the lock in position, and the bolts must align with the strike plates without friction.
Enlarging a mortise without inspecting the door may weaken an already narrow area. On a technical or certified door, any modification must comply with the overall set requirements.
Preparing a replacement
Measure the lock case height, depth and thickness, plus the backset, centres, faceplate shape and dimensions, handle spindle size and screw positions.
The engraved brand and model number can aid in identification. Proper identification often allows retention of handles and the housing rather than replacing the entire door.
Points to check after installation
The handle should return normally and the key should turn smoothly without needing to push or lift the door flap forcefully. Tests are first carried out with the door open, then with the door closed.
A difficulty appearing only when the door is closed often points to strike plate alignment or door flap adjustment. A fault when the door is open may require an inspection of the assembly and mechanism.
IN IMAGES
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