As you change the lock
If the lock to be renewed is of the type with handles, you must first remove the latter, by removing the screws that hold them fixed to the square pin that actuates the latch.
done this, he goes to work on the ledge of the door by removing the screws that secure the housing of the lock to the door.
Once removed applies in the same seat to the corresponding part of the new lock mechanism. This must enter without difficulty: otherwise should be lightly file the wand or spessorarla with thin pieces of wood. If the holes in the new lock coincide or are too close to the previous ones, it is necessary to fill them with fragments of wood and glue and let it dry before attaching the new lock mechanism.
placed the wing, it is now necessary to apply to the fixed frame, and in a position corresponding exactly the metal plate in which the bolt must penetrate. The best way is to pull out the bolt from the lock, pull the door to the frame and mark the position of the bolt. It then fixes the frame the metal plate: also in this case it is necessary to pay attention to the position of the holes.