Adding a lock to a door is a common home security upgrade that is manageable for a dedicated individual with the right tools and guidance. This process involves precise measurements, careful drilling, and the installation of hardware to enhance the security of a residential space. The steps outlined here focus on the installation of standard residential locks, such as deadbolts and keyed knob sets. Successfully completing this project requires attention to detail during the door preparation phase to ensure the lock functions correctly and provides maximum protection.
Choosing the Best Lock for Your Needs
Selecting the appropriate lock requires understanding the balance between security, durability, and intended placement within the home. The American National Standards Institute (ANSI) and the Builders Hardware Manufacturers Association (BHMA) provide a grading system to categorize locks based on rigorous testing for security and longevity. This system ranks locks from Grade 1, offering the highest level of protection, down to Grade 3, which provides basic security for light-duty applications.
For exterior doors, a Grade 1 or Grade 2 lock is recommended to provide sufficient resistance against forced entry and wear. The deadbolt is the most commonly added high-security lock, functioning independently of the door knob or lever to secure the door within the frame. Deadbolts are available as single-cylinder (key on the outside and a thumbturn on the inside) or double-cylinder (key required for both sides).
Keyed knob or lever sets offer a convenient locking mechanism, but they typically provide lower security than a dedicated deadbolt. These locks are often used for interior doors requiring privacy or as a secondary lock on an exterior door. When selecting any residential lock, verify the backset measurement, which is the distance from the door’s edge to the center of the bore hole. The two standard backsets are 2-3/8 inches and 2-3/4 inches, and the lock’s latch mechanism must match the door’s preparation.
Essential Tools and Door Preparation
Before beginning the installation, gathering the correct equipment is necessary, including a power drill, a hole saw kit, a wood chisel, a measuring tape, and a screwdriver. The hole saw kit should include a 2-1/8 inch bit for the main lock body bore hole and a 1-inch bit for the latch’s edge bore hole, as these are the industry standards for most residential locks. Many lock kits provide a specialized installation jig or template, which is a helpful guide for marking and drilling the door accurately.
The preparatory step is accurately marking the door for the bore holes, which determines the lock’s eventual position and function. Align the lock’s template to the door edge, marking the center point for the main 2-1/8 inch bore hole. Ensure the measurement is either 2-3/8 inches or 2-3/4 inches from the door’s edge (the backset). A second mark is made on the door’s edge for the 1-inch edge bore hole, which will house the latch or bolt mechanism. These measurements must be precise, as even a small deviation can cause the lock to bind or misalign with the strike plate on the frame.
Installing the Lock: A Step-by-Step Guide
The physical installation process begins with drilling the two marked holes, starting with the main bore hole through the door face using the 2-1/8 inch hole saw. To prevent splintering the wood on the opposite side, stop drilling as soon as the pilot bit pokes through, and complete the drilling from the reverse side. Once the main hole is complete, the 1-inch edge bore hole is drilled into the door’s edge. This connects to the center of the main bore hole to create a channel for the latch mechanism.
Next, the door edge must be prepared for the latch’s faceplate by creating a shallow recess, a process known as mortising. Insert the latch mechanism into the edge bore hole, and trace its faceplate outline onto the door edge. Carefully carve out this outline using a sharp wood chisel to a depth equal to the plate’s thickness. The faceplate should sit flush with the door’s surface when the latch is installed, ensuring proper alignment with the door frame.
With the door properly bored and mortised, the latch or deadbolt mechanism is inserted into the edge bore hole and secured with two screws through the faceplate. The exterior and interior components of the lock—the cylinders or knobs—are then inserted into the 2-1/8 inch bore hole, aligning the tailpiece of the lock with the mechanism in the door edge. These components are secured to each other with long mounting screws that pass through the interior assembly and thread into the exterior cylinder. This holds the entire lock body tightly in place.
The final step involves installing the strike plate on the door frame, which is the metal piece that receives the latch or deadbolt when the door is closed. Close the door carefully, and extend the lock to mark the exact position where the bolt contacts the frame, ensuring this location is accurately transferred to the door jamb. A recess is created on the jamb to accommodate the bolt throw.
Mortise the door frame to embed the strike plate flush with the frame’s surface, similar to the process used on the door edge. Secure the strike plate with long screws, which should penetrate the door frame’s structural stud to offer maximum resistance against forced entry. Test the smooth operation and alignment immediately after installation.