Cylindrical locks for entry doors are designed with an internal keyed locking mechanism. This type utilizes an internal system which interacts with the trim of the door by inserting and removing a bar. This bar is turned via a handle or a key. This type may be installed alone or as part of a door handle. While there are several variations in the cylinder size as well as its exact placement, these locks are virtually the same.
While fitting a lock cylinder correctly, there are several things that are important. First, the faceplates of a standalone lock cylinder are removed through the screws. Then, the screws on the cover plate that are located in the interior side of the door are identified. They are loosened and the plates that are covering the locking mechanism are removed. After this, the door handles are removed. This is done by unscrewing it around the base portion of the door handle. However, if it is a handle and lock combination, the trim needs to be popped off so the screws that are securing the door handle in place can be accessed. Then, the screws and the knob or handle are removed.
After completing the first steps, a flat headed screwdriver is placed into the spindle, which is located at the centre of the cylinder. This is unlocked this by turning the screwdriver counter clockwise. By doing this, the square tab on the lock is aligned with the square notch found in the internal housing. This should free the lock and then it is easily removed. This can be depressed or the spindle pried gently using the screwdriver to free the spindle from its housing. Using a flat headed screwdriver, gentle pressure can be applied to the tabs while pushing into the hole for the spindle so it will pop out of its housing. To install a new lock cylinder, technicians simply reverse the process of removing one.