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How to Install Locks in Metal Doors

Emily Beach

Metal doors are often used at exterior openings to provide added security and durability. These doors consist of a foam or cardboard core surrounded by a thin metal skin, which may be up to 1/4" thick. The edges of the door are often make with wood to add strength, though this is not always the case. While it is fairly easy to install a lock in a wooden door, it takes a few special tools and techniques to successfully add a lock to a metal door.

  1. Choose your lock. Look for locks with a 2-3/8" backset for residential applications, or a 2-3/4" backset for commercial jobs. Find a lock that complements your decor and can be easily operated by all building occupants.

  2. Remove the lock from the package and examine the enclosed templates. These templates are placed on the door using tape or self-sticking adhesive. Install your templates on the door and frame as directed to help you install the lock in the correct location.

  3. Drill pilot holes on the face of the door as directed on the template. Repeat this process along the edge of the door to create pilot holes for the latch plate.

  4. Use a bi-metal hole saw to cut out a hole for the lock body. Choose a hole saw that is the same size as the hole you plan to cut. It may be helpful to pre-punch the center of the hole with a hammer and nail before you begin. This can prevent damage to the door surface as you cut.

  5. Repeat Step 4 along the edge of the door to create a hole for the latch or bolt. When you've made both holes correctly, you should be able to insert a pencil into the side of the door and have it pass through the hole for the lock body in the face of the door.

  6. Place the lock body into the opening. Hold one knob or lever in each hand and align the spindles and/or connecting rods. Slide the two units together until they are tight to the face of the door on either side. Install screws as indicated on the templates and the lock body. Ensure that the bolt or latch passes successfully through the edge of the door before proceeding. Install the latch plate on the side of the door to cover the side of the lock body.

  7. Use the template to drill holes in for the strike plate in the door jamb. Use your bi-metal hole saw to create a hole for the latch or bolt. If the jamb is made of wood, use a chisel or router for this task. Test that the bolt fits into the strike, then install the strike plate to complete the installation.