When a key goes all the way into a lock but won't turn, the cause is usually one of three things: the key is worn or bent, something inside the cylinder is binding, or the door's bolt is pressed against its strike plate. A few minutes of careful observation, with no force and no tools, can tell you which is most likely.
What has to happen for a key to turn
A key cylinder is the part you put the key into. Inside it sits a row of small spring-loaded pins. The key's cuts lift each pin to the right height so the inner barrel, called the plug, can rotate and move the bolt.
A key that seats but won't turn means one link in that chain has failed. The cuts may no longer lift the pins correctly, something inside the cylinder may be stuck or broken, or the bolt may be jammed against the strike plate, the metal plate on the frame that the bolt slides into.
The point of this page is to observe the lock, not to fix it. Nothing below involves taking anything apart.
What to notice before you try again
You need only your hands and a spare key, if you have one.
- Look at the key's shoulder, the step near the head. If the shoulder isn't flush with the face of the cylinder, the cuts aren't lined up with the pins. That points to a bent key or something lodged in the slot.
- Try a spare. If the spare turns, suspect the first key. If the spare stalls in the same spot, the key is probably not the cause.
- Notice the feel of the stall. A gritty drag or a dead-solid stop leans toward the cylinder. A turn that starts and then quits can mean the bolt is catching on the frame, or the plug is rotating without moving the bolt.
- Use light hand pressure on the door. Ease it toward you, then away, and lift gently on the handle. If the key turns more freely in one position, the bolt is likely binding against the frame.
- Note whether the problem is one lock or several. Trouble confined to one door points at that door's cylinder or latch. Several locks failing with the same key points back at the key.
- Think about when it started. Stiffness that built up over weeks suggests wear. A lock that worked yesterday and quit today suggests something bent, broke, or shifted.
How the clues point to a cause
A worn or damaged key
In this pattern, the spare works, the original doesn't, and the trouble crept in slowly. A worn key has rounded cuts that leave the pins slightly short of where they need to be. That is why a worn key often turns only sometimes, or only after a wiggle.
A problem inside the cylinder
Here every key fails the same way, door position changes nothing, and the stall feels gritty or completely solid. A broken pin or spring, debris, or internal wear can all stop the plug. If the key turns partway and then quits no matter how the door sits, the plug may be moving without engaging the bolt.
A door or latch under strain
In this pattern, the key turns when you push, pull, or lift the door, and only on that door. The lock itself may be fine. The bolt is dragging because the door and frame no longer line up.
These patterns tell you what is likely, not what is certain. A worn key and a tired cylinder can show up together, and a bolt that has been binding for months can wear the lock too.
When should you stop trying the key?
Stop once you have tried the spare and the door positions. Gripping the key with pliers or pushing a tool through the hole in its head puts more twist on the blade than it can take. The key can snap and leave part of it stuck in the cylinder, and a lock that seizes completely can turn a repair into a lockout.
Skip sprays as well. Anything added to the keyway, the slot the key enters, can hold grit and hide the real problem.
A locksmith will want to know these details:
- Which door, and which lock on that door
- Which key, and whether it is an original or a copy
- What happened when you tried the spare
- Whether pushing, pulling, or lifting the door helped
- When the problem started, and whether it came on suddenly or gradually
Williamsburg Locksmith and Key Copy is a mobile locksmith in Williamsburg that also works in Greenpoint, Bushwick, Bed-Stuy, and across Brooklyn, Manhattan, Queens, the Bronx, and Staten Island. Depending on the cause, the answer might be a fresh key copy, door hardware repair, or a lock change or rekey (new pins matched to a new key). If the door won't open at all, 24/7 emergency lockout service is available. Call (347) 699-9268 with your notes in hand.
Frequently asked questions
Is it safe to keep jiggling the key until it turns?
Jiggling a key that won't turn is fine for a moment if the key stays fully seated and you use fingertip pressure. Repeated hard twisting is not. Each round of force bends the key's blade a little and strains the pins and springs inside the cylinder, which makes the original problem worse. If a few light tries haven't worked, more of the same rarely will.
Why does the key turn better when I pull or push the door?
A key turns better with the door pulled or pushed because the bolt is rubbing against the strike plate or the edge of the frame. Doors shift when hinges loosen, frames settle, or wood swells. Once the bolt and its opening stop lining up, the bolt binds and resists the key. The cylinder can be in fine shape, so the fix lies in the door, hinges, or strike plate.
Does a key that won't turn mean I need a new lock?
A key that won't turn does not automatically mean you need a new lock. If a spare works, a fresh key copy may be all that is needed. If door position makes a difference, the door or strike plate is the likely target. Rekeying or replacing the lock mainly comes up when the cylinder itself is worn or broken, which a locksmith can judge with the lock in front of them.
Can a worn key be replaced without changing the lock?
A worn key can usually be replaced without touching the lock, as long as the cylinder is still in good shape. The catch is the source key, because copying a worn key copies its wear. A copy made from a spare that still turns smoothly gives the pins cleaner cuts to follow. If every key you have is worn, say so when you ask about a copy.