How to Install a Deadbolt Lock (DIY Door Security in 1 Hour)

Don't just grab the cheapest deadbolt off the hardware store shelf. Locks are graded - Grade 3 is the basic builder-grade, Grade 2 residential is a step up, and Grade 2 commercial is the sweet spot for most homes.

A Grade 2 commercial deadbolt has heavier internals, a six-pin cylinder, and 3-inch screws for the strike plate. The 3-inch screws are the part that actually matters. The lock body could be made of gold and it wouldn't matter if the strike plate is held in with the standard 3/4-inch screws that come with most kits.

The latch (the piece that slides through the edge of the door) is adjustable on almost every modern deadbolt. It switches between 2-3/8 inch and 2-3/4 inch by sliding or rotating a collar on the bolt.

Backset is the distance from the door edge to the center of the bore hole. Measure yours with a tape - hold it from the edge of the door to the middle of the round hole on the face. If it's 2-3/8 inch, set the latch short. If 2-3/4 inch, set it long. Getting this wrong means the latch won't reach the slot inside the cylinder housing.

Slide the latch into the hole on the edge of the door, faceplate flush against the wood. The bolt itself should pull and push freely - that's how you know it's seated right.

Drive the two latch screws into the pre-drilled pilot holes on the door edge. Phillips screwdriver, or a drill with the clutch dialed back. Don't crank these down hard. The faceplate should sit flush, not bite into the wood.

Now the lock itself. The exterior side has the keyway - that's the side that goes on the outside of your door, facing the street.

Twist the tail piece (the small flat metal tab sticking out the back of the cylinder) so it's horizontal. Slide the whole cylinder through the round bore hole on the door, threading the tail piece through the matching slot in the latch you just installed. The decorative ring should sit flat against the door face.

Hold the exterior cylinder square against the door with one hand. With the other, line up the interior back plate (the side with the thumbturn) and slip it onto the two posts coming through from the front.

Drive the two connecting screws through the back plate into those posts. Tighten them alternately - a couple turns on the left, a couple on the right - so the lock pulls together evenly. Crank one all the way down first and you'll bind the cylinder.

Before you fully torque anything down, test the lock. Turn the thumbturn back and forth. Then try the key from the outside. The bolt should slide in and out smoothly with light pressure.

If it sticks, grinds, or feels stiff, back the connecting screws off about a quarter-turn each. Over-tightening is the number one reason a brand-new deadbolt feels notchy. The cylinder needs a tiny bit of float to spin freely.

Open the door and find the spot on the door jamb where the bolt lines up. The existing strike plate (the small metal plate on the jamb) marks the spot. Pop it off and look at the cavity behind it.

Chuck a 1/8-inch bit in your drill and bore two pilot holes inside that cavity - one near the top, one near the bottom. Go straight in, about 2-1/2 inches deep. The pilot holes prevent the door jamb from splitting when you drive the long screws.

Set the new strike plate over the cavity and drive the 3-inch screws through it into the pilot holes you just drilled. This is the single most important step in the whole install.

The screws that come with most basic deadbolt kits are only about 3/4-inch long. They bite into the jamb trim and nothing else - one good kick and the whole plate rips out. The 3-inch screws push through the jamb and anchor into the framing stud behind it. That's what turns your door from "kickable" into "actually locked."

Close the door and turn the thumbturn. The bolt should slide all the way out into the strike plate cavity. Fully extended - not stopping halfway, not hanging at an angle.

A partially extended bolt is the same as no bolt. Any push on the door will compress the spring and pop it back in. If the bolt only goes part way, something inside the strike cavity is in the way. That's the next step.

If the bolt hits wood inside the strike plate cavity, you'll need to chisel out a little extra room. Mark the spot where it's hitting (a strip of pencil lead on the bolt tip, throw the bolt, see where the mark transfers).

Take a sharp wood chisel and shave small bites out of the cavity. Re-test after every pass. You want the bolt to drop fully into place under its own weight, not be forced in. Once it does, you're done. Your door is genuinely locked now, not just latched.