Deadbolt Installation Basics: Stronger Front Doors
A good deadbolt installed badly is just decoration. If the bolt doesn’t fully extend, doesn’t line up with the strike, or only bites into soft trim wood, your “security upgrade” is mostly cosmetic. This guide walks through the basics of putting a deadbolt in correctly so it actually works with a reinforced frame. If you haven’t picked a lock yet, start with Best Door and Window Locks.
1. Choose the Right Deadbolt First
Installation can’t fix a weak lock. Before you drill anything, make sure you’re working with a solid Grade 1 or at least Grade 2 deadbolt.
Minimum requirements
- Single-cylinder deadbolt for most exterior doors (key outside, thumb-turn inside).
- 1-inch bolt throw (the part that extends into the frame).
- Solid steel bolt and reinforced housing.
Full details on grading and lock types are covered in the lock selection guide, so this article focuses on the install itself.
2. Standard Deadbolt Height and Layout
Most deadbolts sit about 6–12 inches above the door handle. You can adjust within that range, but staying near the standard height makes hardware and strike alignment easier.
Layout basics
- Mark centerline at the same vertical line as the door handle latch.
- Measure up 6–8 inches from the top of the handle and mark the deadbolt center.
- Use the template included with the deadbolt kit to confirm hole placement.
If the door or frame is already reinforced (see Reinforcing Door Frames), make sure your new location still lines up with strengthened wood and strike plates.
3. Drilling the Cross Bore and Edge Bore
Most deadbolts need two holes: a large cross bore through the face of the door, and a smaller edge bore for the bolt assembly.
Cross bore (face hole)
- Typically 2-1/8" diameter for modern deadbolts.
- Use a hole saw and drill from one side until the pilot bit exits.
- Finish drilling from the other side to prevent splintering.
Edge bore (bolt hole)
- Typically 1" diameter.
- Drill straight into the door edge at the marked centerline.
- Ensure the hole is deep enough for the entire bolt assembly.
Take your time on alignment. A crooked hole will cause binding, which leads to people “living with it” instead of locking the door every time.
4. Mortising the Bolt Faceplate
The bolt faceplate should sit flush with the door edge. If it sticks out, it will drag on the frame and wear quickly.
Mortise steps
- Outline the faceplate with a utility knife or pencil.
- Use a chisel to remove a shallow layer of wood inside the outline.
- Test fit until the plate sits flush with the edge.
Do the same on the frame for the strike plate if you’re installing a new one. A flush fit also makes weather stripping seal better, which helps with drafts and HVAC efficiency—small side benefit.
5. Installing the Deadbolt Body and Thumb-Turn
Once the holes are clean, installing the hardware is straightforward.
- Insert the bolt assembly into the edge bore with the “top” arrow facing up.
- Attach the interior and exterior pieces through the cross bore.
- Align the tailpiece so the thumb-turn rotates smoothly.
- Tighten screws evenly so the lock doesn’t twist or bind.
Test the deadbolt with the door open. It should throw and retract smoothly by key and by thumb-turn, with no grinding or sticking.
6. Positioning and Reinforcing the Strike Plate
The strike plate is where most installs fail. If the bolt barely enters the strike or only hits trim wood, the door is still weak.
Strike location
- Close the door and mark where the bolt hits the frame.
- Center the strike opening on that mark.
- Mortise the strike so it sits flush in the frame.
Reinforcing the strike
- Use a heavy-duty strike plate, not a thin decorative one.
- Replace factory screws with 3" screws into the stud.
- Confirm the bolt fully extends into the strike by at least 1".
For deeper reinforcement options (jamb shields, hinge upgrades, full-frame kits), see Reinforcing Door Frames.
7. Alignment and Final Adjustments
If the bolt drags or doesn’t seat fully, it won’t be used consistently. Fix alignment issues now instead of forcing the lock and wearing it out.
- Adjust the strike plate position slightly up, down, in, or out as needed.
- Check the door for sagging hinges—tighten or re-screw with longer fasteners.
- Verify weather stripping isn’t blocking the bolt path.
Once tuned, the deadbolt should lock with a single, smooth turn—no shoulder pressure on the door required.
8. Testing the Finished Install
Test the door like a normal user and like someone trying to force their way in.
- Lock and unlock multiple times with both key and thumb-turn.
- Push and pull on the door while locking to check for binding.
- From the outside, pull firmly on the handle to feel movement in the frame.
- Confirm the door still closes cleanly without slamming.
If the install passes these tests and the frame is reinforced, you’ve significantly raised the effort needed to kick the door in. That physical security pairs well with any alarm system you install later (see Home Security Systems Explained for how locks and alarms work together).