How to Replace a Deadbolt and Entry Lockset

Planning Your Lock Replacement

Replacing a deadbolt and entry lockset is one of the most straightforward upgrades a homeowner can tackle. The job takes about an hour, requires only basic tools, and dramatically improves both security and appearance. Before buying hardware, measure your door’s thickness (standard is 1-3/4 inches) and the backset — the distance from the door edge to the center of the hole: typically 2-3/8 or 2-3/4 inches. Choose a lockset that matches these dimensions; adjustable latches make future replacements easier.

Standard placement puts the deadbolt cylinder center 48 inches above the floor, and the handle center at 36 inches. Check that the new deadbolt’s latch hole is 1 inch in diameter and the cylinder hole is 2-1/8 inches — these are universal sizes for residential locks. If your existing holes match, you can skip all drilling. If they are slightly off, you may need an adapter plate or a hole saw.

Choosing a Lockset

Look for a Grade 1 or Grade 2 deadbolt (ANSI/BHMA rating). Grade 1 is commercial grade, best for high-traffic doors; Grade 2 is suitable for most entry doors. The latch should have a hardened steel bolt that extends at least 1 inch into the strike plate. “Keyed alike” sets let both locks open with the same key, saving you from carrying multiple keys. Smart locks add convenience but require batteries and pairing; the installation steps are similar.

Step-by-Step Installation

1. Remove the Old Hardware

Start on the interior side. Unscrew the two or three screws holding the deadbolt’s interior trim. Lift the interior plate off, then pull the exterior cylinder out. The latch assembly on the door edge is held by two small screws; remove those and slide the latch out. Repeat for the entry handle — usually two screws behind the interior handle plate. Keep all old screws in a bag in case you need spares.

2. Prepare the Door for the New Deadbolt

If your door lacks a deadbolt, you must drill two holes. Mark the center height on the door face 2-1/8 inches from the edge. Drill a pilot hole through both faces. Using a 2-1/8 inch hole saw, drill from one side until the pilot bit breaks through, then finish from the opposite side to avoid tear-out. For the latch hole, drill a 1 inch hole in the door edge centered on the cylinder hole. A spade bit works; clamp a scrap block on the opposite side to prevent splintering.

3. Install the Deadbolt Latch Assembly

Slide the latch into the edge hole with the beveled side facing inward (the flat side faces the door interior). Fasten with two screws, checking that the latch moves freely. The faceplate must be flush with the door edge — not protruding. If it is too deep, chisel the mortise deeper; if it sticks out, chisel a few extra passes. A flush fit is critical for the deadbolt to slide smoothly.

4. Mount the Deadbolt Cylinder and Thumb Turn

Feed the exterior cylinder through the face hole, aligning its tailpiece with the latch’s drive mechanism. From inside, attach the thumb turn over the tailpiece and tighten the two machine screws. Tighten evenly until snug — overtightening can warp the trim or bind the bolt. Install the strike plate on the jamb. Mark its position by closing the door and extending the deadbolt. Mortise the strike plate flush using a chisel so it sits flat. The deadbolt should fully extend into the strike plate without scraping.

5. Install the Entry Lockset

The entry handle uses a similar procedure: insert its latch assembly into the edge hole (bevel inward). Fasten it. Place the exterior handle through its hole, passing the spindle through the latch. Attach the interior handle, aligning the spindle and any anti-rotation tabs. Secure with the mounting screws. The handle should retract the latch smoothly when turned.

6. Align Strikes and Test

Close the door and check each latch’s alignment with its strike. If the deadbolt binds against the strike plate, file the strike’s opening slightly larger in the direction of the bind. For the handle, if it doesn’t close easily, the strike may need repositioning — remove the strike, fill old holes with wood plugs, and redrill. Once aligned, test both locks from inside (use the thumb turn) and outside (use the key). The operation should be effortless.

7. Final Security Check

Tighten all screws. Ensure the deadbolt extends at least 1 inch. Confirm the thumb turn and key turn smoothly. If the deadbolt sticks, check that the door is properly closed and the latch fully retracted; a sticking bolt often indicates a misaligned strike or a gap between the door and jamb. Install any cosmetic trim rings. Wipe the hardware clean.

Common Mistakes to Avoid

• Skipping the mortise: A strike plate or latch plate that isn’t flush will keep the door from closing fully or cause the latch to drag. Always chisel a shallow mortise.
• Overtightening screws: Machine screws on the cylinder can strip or bind the latch if overtorqued. Snug is good; gorilla is not.
• Wrong backset: A 2-3/4 inch backset latch won’t fit in a 2-3/8 inch hole, and vice versa. Measure twice.
• Not checking for square: If the door is not square to the frame, a new lockset won’t align. Check the gap between door and jamb. If uneven, you may need to adjust hinges first.

Safety

Safety is important during any home project. When drilling into a door, secure the door with a doorstop or have an assistant hold it steady to prevent it from swinging. Wear safety glasses when drilling or chiseling — wood chips and metal filings can fly. If you use a hole saw, ensure the pilot bit is centered; a wandering hole saw can ruin the door. Keep all sharp tools, chisels, and screwdrivers in good condition to prevent slips. When testing the locks, always have a key on the outside before closing the door completely to avoid locking yourself out accidentally. For fire safety, do not install a deadbolt that requires a key from the inside on egress doors; use a thumb-turn instead.