An actual strong lock would be a bar across the door on the inside it would hang on the inside main hinge side of the doorframe and then latch into something on the other side with the metal or wood bar blocking the middle hinge in the process.
How to keep bifold door locked.
Adjusting the position of the door photo 1.
You then feed the lock from the back to the front and secure it with the included screws.
You don t drill it on the overlap but next to it.
Many vinyl and pine doors are thinner than oak or other hardwood doors.
Slip one end of the top mount lock.
The lock body itself should cover the folding portion of the lock.
The latch locks on the door can easily be compromised so you want to make sure that the doors have a secondary level of security to deter burglars and offer up a good fight.
Insert a padlock through the hasp to keep the door locked except when opened with a key.
Purchase a top mount lock based on the thickness of the doors.
A good way of doing this is to insert a bar into the tracks of the door to impede movement and prevent them from being opened.
Install a hasp so that one end sits on one side of the folding section and one sits on the other.
To install the lock you drill a 1 diameter hole on the front door near the edge where the two doors overlap.
For a simple single bifold door lock consider using a padlock.
Short video showing how to use my 3d printed bi fold door lock.
When you operate the lock a tongue on the back lifts up.