If the doorknob is on the left you need a left handed door.
How to fit a internal door lock.
Open the door and stand with your back to the hinges.
Tape measure pencil flat drill bit for wo.
Create a mortise for the plate around the latch on your door using the technique described above.
This process will vary somewhat based on the doorknob you are installing.
First mark out the place where the strike plate has to be fitted.
Mark out the strike plate on the door frame after you ve fitted the lock in the door you need to fit the strike plate to the door frame.
Begin by removing the screws from the door knob on the interior side of your door.
Create a mortise and holes for your lock and door handle.
Hold the door latch against the face of the door flush with the door edge and mark the spindle centre on your previously marked centre line see fig 1.
This allows you to pull the door knobs off the door from both sides.
In some cases door latch plate mortises might need to be cut or enlarged.
Then use a drill to make the necessary holes for installation of your doorknob door handle and lock.
Remove the two screws from the latch plate on the edge of the door and remove the latch from the opening.
This video is about how to fit a door latch and door handle in an interior door.
Tools needed for this job.
Turn the key so the locking bolt protrudes from the lock and hold the door against the door frame.
If you re installing a pre hung door make sure you get the correct swing determined by the placement of the hinges and doorknob.
Shake the door a bit to make sure it is secure.
Purchase a door stop or professional grade door wedge from a local hardware store or from an online retailer.
If the knob is to the right select a right handed door.