If your key will not turn in the lock, stop applying force immediately. The most common causes are a bolt binding because the door or frame has shifted, a worn or badly cut key, debris and dried lubricant inside the cylinder, a cold-contracted or frozen lock, or a worn cylinder. Forcing a stuck key is what turns a five-minute fix into a broken key extraction or a full lock replacement.
A house key is soft brass; the cylinder and bolt it drives are steel. Add leverage with pliers or a screwdriver through the key bow and the key is always the part that gives, and a snapped tip in the keyway removes every easy option you had a moment earlier. If the key does not turn under the light pressure you use every day, something mechanical is wrong, and more force will not fix a mechanical problem.
How the key behaves tells you where the fault is. Match your situation to one of these four patterns first.
Something is inside the keyway: debris, a broken fragment from an earlier attempt, a bent key, or ice in cold weather. It can also simply be the wrong key, which happens more often than people expect when several keys on a ring share a profile.
A solid cylinder means the pins are not reaching the shear line: a worn key, a badly cut duplicate, the wrong key, or pins that are gummed up or damaged. If the key is new, suspect the copy.
This is the signature of binding: the cylinder turns fine, but the bolt cannot move because the door is pressing against the strike plate or frame. It is the most common cause in NYC buildings and is usually fixable without touching the lock.
If the key spins with no resistance and the bolt never moves, the link between cylinder and locking mechanism has failed: a backed-out set screw, a sheared tailpiece or cam, or a broken part inside a mortise lock body. This one always needs a locksmith.
NYC housing stock is old and constantly moving. Buildings settle, wood doors swell in humid summers and shrink in dry winters, and heavy steel apartment doors sag on their hinges. Once the bolt no longer lines up with the strike plate hole, it binds against metal and the key cannot finish its rotation. The tell: the key turns easily with the door open and refuses when it is closed. If so, the lock is fine and the door is the problem, covered in why your door will not lock properly.
Every insertion wears brass off the cuts until the peaks flatten enough that the pins no longer lift correctly. The same happens instantly when a key is duplicated from another duplicate, since each generation compounds the error before it. Test it: if a different key for the same lock works, the lock is healthy and the key is worn out. Cut a fresh key from the original or the lock code, never from the worn copy. See getting keys copied in NYC.
Street grit, pocket lint, and residue from old oil-based sprays collect in the pin chambers and build into a sticky film that stops pins dropping cleanly. Ground-floor entrances and storefront doors collect it fastest.
In a New York winter, moisture inside a cylinder can freeze and metal parts contract at different rates, so a lock that worked in October seizes in January. That is a seasonal pattern with its own right and wrong responses, covered in what to do when a lock freezes in winter.
Pins, springs, and the plug wear out. A cylinder subjected to an attempted break-in, or simply used tens of thousands of times, can reach the point where no key operates it reliably. The fix is usually lock cylinder replacement rather than a whole new lock body.
If a key was forced recently, part of the tip may still be blocking the keyway. Shine a light straight in before trying anything else. See what to do when a key breaks inside a lock for why fishing with tweezers usually drives the fragment deeper.
Many older Manhattan, Brooklyn, and Bronx buildings use mortise locks set into a pocket in the door edge. They have more internal moving parts than a modern deadbolt, so the fault can be in the lock body rather than the cylinder. One that has stiffened gradually over months is wearing out.
If a key that worked yesterday will not enter today, the cylinder may have been changed. In New York City a landlord cannot lawfully lock a tenant out without a court order, and a self-help lockout is illegal. If that is what happened, call 311 or the police rather than a locksmith, and see who pays for a locksmith.
Work through these in order, and stop entirely if the key starts to flex.
Each of these reliably converts a repairable lock into a replaceable one.
| What the key does | Most likely cause | Typical fix |
|---|---|---|
| Turns when the door is open, binds when closed | Door or strike plate misalignment | Adjust hinges or reposition the strike plate |
| Enters fully, will not rotate, spare key works | Worn or poorly cut key | Cut a fresh key from the original or lock code |
| Gritty and stiff, worsening over months | Debris and dried lubricant in the cylinder | Clean and re-lubricate with a dry lubricant |
| Seized only in cold weather | Moisture freezing inside the cylinder | Thaw safely, dry, then apply dry lubricant |
| Will not insert at all | Obstruction or broken key fragment | Professional extraction, then inspection |
| Spins freely, bolt never moves | Broken tailpiece, cam, or lock body | Cylinder or full lock replacement |
Call rather than continue if the key has started to bend, you can see a fragment in the keyway, the cylinder spins without moving the bolt, the lock has failed repeatedly in recent weeks, or you are outside with no other way in. A jammed lock inside an occupied apartment is urgent too: a door that cannot be unlocked from the inside is an egress hazard. If you cannot get in at all, that is a lockout rather than a repair: see emergency lockout service and apartment lockout help.
A technician starts by reproducing the symptom, because the fix depends on which pattern is present. From there the work is usually one of: adjusting the door or strike so the bolt clears, cleaning and re-lubricating the cylinder, cutting a correct key from the lock, extracting a fragment, replacing the cylinder, or replacing a failed lock body. Emergency Locksmith NY is licensed and insured, covers all five boroughs, and typically arrives in roughly 15 to 20 minutes depending on traffic.
Stop before the key snaps. Our licensed locksmiths diagnose and repair jammed locks across Brooklyn, Manhattan, Queens, the Bronx, and Staten Island, 24 hours a day.
Lubricate exterior locks with dry graphite or PTFE once or twice a year, before winter. Replace keys when the cuts visibly flatten, duplicate from an original rather than a copy, and fix a sticking door the first time you notice it.
A sudden failure is almost always mechanical rather than gradual wear. The usual causes are the door shifting so the bolt binds against the strike plate, cold weather freezing the cylinder, fresh debris in the keyway, or a broken key fragment from an earlier attempt. If the key turns fine with the door open but not closed, the door is the problem, not the lock.
No. Penetrating oil sprays can free a lock briefly, but they attract grit and leave a residue that makes the cylinder worse within weeks. Use a dry lubricant instead: powdered graphite or a PTFE lock lubricant. Puff a little into the keyway, work the key in and out, then try again with light pressure.
Yes, and it is very common. Brass keys wear with use, and duplicates cut from other duplicates compound small errors until the cuts no longer lift the pins correctly. If a different key for the same lock works normally, your key is the problem. Have a new one cut from the original or the lock code.
If the key rotates with no resistance and the bolt never moves, the link between the cylinder and the locking mechanism has failed: a backed-out set screw, a sheared tailpiece or cam, or a broken part inside a mortise lock body. Lubricant will not fix that, and it needs a locksmith.
It can be. If you cannot get into your home, or a door cannot be unlocked from the inside, treat it as urgent: a door that will not open from the inside is an egress hazard. Emergency Locksmith NY provides 24-hour service in all five boroughs. Call (718) 412-1332 and describe what the key is doing.