How To Replace a Common Door Lock

Replacing a door lock is a straightforward home improvement project that can improve your home’s security and update its appearance. In this guide, we’ll explore the steps to replacing a common door lock, exploring the differences between older mortise locks and newer cylindrical models. In the video above, Ask This Old House expert Nathan Gilbert shows host Kevin O’Connor the simplicity of modern lockset installation and repair.

*Unless otherwise noted, costs in this article reflect an average of prices that our team found from hardware stores like Lowes and Home Depot, and on Amazon.com.

Understanding Door Lock Types

Modern cylindrical locksets have simplified the replacement process, making it accessible for many homeowners to tackle themselves. Before diving into the replacement process, here are the different types of door locks you might encounter.

Mortise Locks vs. Cylindrical Locks

Mortise locks, once common in residential settings, are now primarily found in high-end homes and commercial buildings. These locks are characterized by their complex mechanisms and require a large pocket (mortise) to be cut into the door for installation.

Cylindrical locks, on the other hand, have become the standard for most modern homes. These locks are named for their cylindrical shape and the round hole drilled into the door to accommodate them. Gilbert points out that cylindrical locks are much easier to install and replace, often requiring just a few screws to secure them in place.

Components of a Cylindrical Lock

A typical cylindrical lock consists of several key components:

• Latch: The part that extends into the door frame to secure the door
• Cylinder: Houses the locking mechanism and keyway
• Doorknob or lever: The part you grasp to open the door
• Faceplate: Covers the edge of the door where the latch extends
• Strike plate: Mounted on the door frame to receive the latch

Preparing for Lock Replacement

Before you begin replacing your door lock, gather the necessary tools and materials:

• Screwdrivers (flathead and Phillips head)
• New lockset
• Measuring tape
• Pencil
• Drill with appropriate bits (if needed)
• Chisel (if adjustments to the door are required)

Choosing the Right Lockset

When selecting a new lockset, consider the door thickness, backset, function, and finish.

Make sure the new lock is compatible with your door’s dimensions and measure the distance from the edge of the door to the center of the existing lock hole. Then, decide whether you need a privacy lock, passage lock, or entry lock. Lastly, pick a design that complements other handles and locks in your home. 

Steps To Replace a Door Lock

Now that you’re prepared, let’s walk through the process of replacing a door lock. These steps apply to most modern cylindrical locksets.

1. Start by removing the two screws holding the deadbolt thumb turn onto the door. Remove the thumb turn and pull the deadbolt cylinder out from the front of the door.
2. Remove the two screws holding the deadbolt into the jamb side of the door. Slide the bolt out once loose.
3. Remove the set screw holding the doorknob onto the lockset and remove the knob. Remove the two screws holding the interior of the lockset to the door and remove it. For thumb-activated knobs, remove the screw holding the bottom of the exterior door knob set in place and remove the doorknob.
4. Remove the two screws holding the latch into the jamb side of the door and pull the latch out of the door.
5. Slide the new deadbolt through the top hole in the jamb side of the door. Leave it loose at first.
6. Slide the exterior portion of the deadbolt cylinder through the top hole on the exterior of the door. Slide the interior piece over the shaft on the inside of the door, and insert the two screws holding the two halves together. Thread the two screws into the jamb side of the deadbolt and then tighten the other screws. Check the deadbolt for operation.
7. Slide the latch into the lower hole on the jamb side of the door. Be sure that the curved side of the latch is facing the jamb to allow it to operate correctly. Leave the two screws holding the latch out of the door for now.
8. Slide the exterior half of the doorknob through the lower hole on the exterior side of the door. Slide the interior collar in place and insert the two screws holding the two halves together. Tighten the screws holding the latch into the jamb side of the door and then tighten the other screws. Check the lockset for operation.

In the video above, Gilbert shows how quickly you can install these modern locksets, often taking just a few minutes to complete.

Tips for a Successful Door Lock Installation

To help your lock replacement go smoothly, double-check measurements before purchasing a new lockset. Keep all screws and small parts organized during the removal and lubricate the new lock mechanism for smooth operation. Test the lock thoroughly before considering the job complete. 

Using Installation Templates

Many modern locksets come with installation templates, which can greatly simplify the process. These templates help you mark the correct positions for drilling holes if you’re installing a lock on a new door or need to adjust an existing one.

To use a template, cut out the template provided with your lockset and align it with the edge of your door. Then, mark the centers for drilling and use the appropriate size hole saw to create the openings you need. 

Adjusting Door Fit

Sometimes, a door may need slight adjustments to accommodate a new lock. If the latch doesn’t align properly with the strike plate, you may need to adjust the strike plate position, file the strike plate opening slightly, or reposition the door hinges.

Maintaining Your New Lock

Once you’ve successfully installed your new door lock, proper maintenance will aid in its longevity and continued smooth operation.

Regular Cleaning and Lubrication

To keep your lock in top condition, clean the lock mechanism annually with a dry cloth and apply a silicone-based lubricant to the moving parts. You should avoid using oil-based lubricants, which can attract dirt and grime, and tighten any loose screws as soon as you notice them. 

When To Seek Professional Help

While replacing a door lock is often a DIY-friendly task, there are situations where professional assistance may be necessary:

• If the door frame is damaged or misaligned
• When dealing with smart locks or complex security systems
• If you encounter unexpected issues during the installation
• For high-security or specialized lock systems

Our Conclusion

Replacing a door lock is a manageable DIY project that can significantly improve your home’s security and give your door a fresh look. With the right tools, a compatible lockset, and careful attention to detail, most homeowners can successfully install a new cylindrical lock in under an hour. Remember to choose a lock that fits your door and security needs, and don’t hesitate to seek professional help if you face any challenges during the process.

Material

• Lockset

Tool