How to Add a Lock to a Door

Strengthening a Door Frame

• 1

  Insert a flat metal putty knife or thin, flat pry bar between the wall and door molding and pry the molding off. Pull the weather stripping out of the groove. This exposes a void space between the wall and door frame.

• 2

  Measure the size of the break between the wall frame and door casing. Cut pieces of wood to fit into the gaps and insert them into the void spaces.

• 3

  Position screws that are sufficient to penetrate the door frame, wood insert and wall framing on the door frame. Use a power drill to sink the screws through the door frame, wood insert and into the wall stud.

Lock Installation

• 4

  Secure the paper template, from the lock kit, onto the door with tape. Position a nail on the marked center of the template on the door front. Press the nail through the template by hand to leave a mark on the door or lightly tap the nail once with a mallet to make a mark on the door. Use the template, as a guide, to mark the door's edge with a nail to designate the latch bolt.

• 5

  Align the mandrel on a hole saw with the mark and bore a hole into the door. Stop boring when the mandrel penetrates the opposite side of the door. Move the hole saw to the opposite side of the door. Align the mandrel with the hole and drill through to complete the hole. Insert a spade bit into the power drill and bore a hole into the door's edge for the latch bolt.

• 6

  Position the latch bolt into the hole on the door's edge. Use a pencil to trace the latch plate. Position a wood chisel at a 60-degree angle on the line and strike the chisel with a mallet to take away the wood from the space inside the drawn lines. The depth of the chiseled section equals the thickness of the latch plate. Put the latch bolt into the chiseled section and secure it in place with screws.

• 7

  Align the lock with the hole and hold it in place. Insert the second half of the lock by sliding the protruding metal bar through the metal latch mechanism inside the hole. Press the two halves together to secure them.

• 8

  Color the end of the bolt that is sticking out from the side of the door with brightly colored chalk. Close the door and turn the handle two to three times. This leaves a color imprint on the doorjamb. Line up the metal strike plate with the chalk imprint and secure it in place with screws.