What goes wrong when people try to change their own locks in a Brooklyn apartment?

Most DIY lock changes in Brooklyn apartments go wrong before the new lock even comes out of the box. The door is the problem, not the lock. Prewar walk-ups in Williamsburg, Bed-Stuy, and Greenpoint have doors that have been painted, planed, warped, and shimmed for a hundred years. A lock that installs in twenty minutes on a new construction door in Downtown Brooklyn can take two hours on a 1920s brownstone door, and that is assuming nothing breaks along the way.

What are the most common mistakes people make when doing a DIY lock change?

The first mistake is buying the wrong lock for the door. Every door has a backset - the distance from the door edge to the center of the borehole. Most prewar Williamsburg apartment doors use a 2-3/8 inch backset. Newer buildings often use 2-3/4 inch. If you grab a Schlage B60N or a Kwikset 980 off the shelf without measuring first, you may get a spring loaded latch that does not align with the strike plate at all.

The second mistake is skipping door prep. A residential deadbolt needs two clean holes - a large edge bore through the face of the door and a smaller bore through the edge. People use a spade bit when they should use a hole saw, and they skip the deadbolt template that ships with every Schlage or Kwikset lock. The template exists for a reason. Without it, the holes land off-center and the lock cylinder either binds in the chassis or spins freely when you turn the key.

The third mistake is ignoring the frame. You can install a perfect Medeco B262 deadbolt and still get kicked in because the strike plate is held by half-inch screws going into soft wood. The fix is a Mag Security or Prime-Line heavy-duty strike with 3-inch screws driven into the stud. Most DIYers skip this entirely.

What goes wrong specifically with smart locks and SmartKey rekey attempts?

Self-install smart locks are marketed as easy, and some of them genuinely are - on the right door. A Schlage Encode Plus or an August Wi-Fi Smart Lock Pro that mounts over an existing deadbolt is a real beginner option. You are not drilling anything. But a battery door lock like the Yale Assure Lock 2 or the Schlage BE489 requires correct door prep from the start. If the existing borehole is not clean or the door thickness is outside spec, the chassis will not sit flush and the bolt will bind every single time.

The SmartKey rekey system on Kwikset locks is a different problem. Kwikset SmartKey is designed so a homeowner or tenant can rekey the lock with a small tool and a working key. It works well when the procedure is followed exactly. But people rush it. They insert the current key, turn it the wrong direction, or use a bent key. When the SmartKey mechanism is reset incorrectly, the pin tumbler stack inside jams and the lock stops functioning entirely. At that point, the lock needs to be replaced, not rekeyed. A locksmith can sometimes recover it, but often the cylinder is done. That is a more expensive outcome than just having a locksmith rekey it from the start.

Smart locks also have a keyway compatibility issue that surprises people. If you are doing a lock cylinder swap on a building that uses a master key system, a new smart lock with a different keyway breaks the whole master key setup. Landlords and supers in Greenpoint and Bushwick buildings run into this constantly. You cannot just swap one cylinder without thinking about the rest of the system.

What door problems make a DIY lock change too risky to attempt yourself?

Start with hinge sag. A door that drags on the floor or sticks at the top has hinge sag, and no new lock fixes that. The door is not square in the frame, so any bolt you install will bind or miss the strike. You can see it with a level. If the gap between the door and frame is wider at the bottom than the top, call a pro before touching the lock.

Mortise locks are another hard stop for most DIYers. A lot of older Williamsburg and Bed-Stuy brownstone doors use mortise locks, and replacing one means chiseling out a precise rectangular pocket in the door edge - what locksmiths call a chisel mortise. Getting the depth and width right requires practice. Too deep and you weaken the door. Too shallow and the lock body protrudes and the door will not close. Drilling pilot holes in the wrong spot on a mortise door can split a door that costs more to replace than a professional install would have cost.

Frame condition matters too. A door frame with an old, poorly aligned strike plate, missing weatherstripping, a damaged door sweep, or a broken astragal on a double door needs more than a lock swap. These gaps affect both security and how the latch engages. A new Schlage B60N will not latch reliably on a frame where the strike plate alignment is off by more than an eighth of an inch. You will end up mortising the strike deeper or shimming the plate, and at that point you are doing real carpentry work on a rental apartment door.

When the door itself is the problem - warped, sagging, or fitted with a mortise lock - put the tools down. Walk into B & G Locksmith at 210 Robeling St in Williamsburg, or call us at (347) 699-9268. We are the locksmith counter inside B & G Hardware, and we can cut keys while you wait, pull hardware off the shelf, and send someone to your door the same day.

Frequently asked questions

Can I rekey my own lock instead of replacing it?

Yes, but it depends on the lock. A Kwikset SmartKey deadbolt lets you rekey it yourself with the tool that ships in the box. A standard pin tumbler lock requires a plug follower, a pinning kit, and real practice. Most renters in Williamsburg brownstones are better off having a locksmith rekey it - it is faster, cheaper than a full swap, and the cylinder goes back in correctly.

What backset do Brooklyn apartment doors usually have?

Most prewar walk-up and brownstone doors in Williamsburg, Bed-Stuy, and Greenpoint use a 2-3/8 inch backset. Newer construction often uses a 2-3/4 inch backset. Measure from the edge of the door to the center of the existing borehole before you buy anything. Getting this wrong means the latch does not reach the strike plate.

When should I stop the DIY and call a locksmith?

Stop when you see a mortise lock, a damaged door frame, a hinge that is visibly sagging, or a strike plate that is already reinforced with a Mag Security strike. These are not beginner jobs. Call B & G Locksmith at (347) 699-9268 or walk in to the counter at 210 Robeling St in Williamsburg.