How to Mount an Internal Deadbolt Lock

Remove the cylindrical shaped deadbolt from the deadbolt kit. It will have two distinct ends on it. One end has the round cylinder and the other end has a rectangular locking mechanism. Insert the rectangular mechanism into the 1-inch hole on the side of the door.

Look through the hole on the side of the door. You will be able to see the cylinder. Turn the cylinder so that the flat side of the mechanism is facing the door. You will be able to see through the mechanism where the screws will penetrate.

Tap on the end of the cylinder with a hammer to make it flush with the side of the door. It is designed to tighten into the hole as it penetrates. Stop tapping when it is flush.

Pick up the lock. Look at the lock by its keyhole and a long protruding piece of metal coming out the back. This is the tailpiece. Insert the tailpiece through the hole from the outside of the door. The tailpiece will penetrate through the mechanism. It can only pass through in one place. When the tailpiece is all the way through the hole and the lock is flush against the outside of the door, let go.

Pick up the secure plate. It is the only flat plate left in the kit. The tailpiece will be visible, extending out through the hole on the inside of the door. Slide the secure plate over the tailpiece and make it flush against the door.

Remove two long bolts from the package. Insert them through the two holes in the secure plate. The screws will penetrate through the mechanism and into the lock on the outside. Tighten the bolts with a Phillips screwdriver.

Remove the thumb lock lever from the package. Place it on top of the secure plate with the lock lever facing straight up. Place the two remaining screws through the holes on the lock lever and tighten with the screwdriver.