Common Locksmith Problems: “The key is just spinning in the lock”

“My key is just spinning in the lock.” This is a very common problem and, to understand why it happens, we need to discuss how cylinder locks work.

The cylinder consists of a plug, which is pretty much the key hole, and then either a tailbar (if it’s a Yale cylinder) or various connecting pieces and a cam if it’s a euro cylinder. The innards of a cylinder lock all do the same thing: they are the bits that engage the cylinder with the actual lock. They convert the action of turning a key into the resultant thrown locking bolt.

If there’s something wrong with the connecting pieces, in other words if the cylinder and the lock aren’t connected properly, then the key will just spin in the cylinder, without opening the door.

Why does it happen?

Let’s talk about Yale locks and euro cylinders separately.

Yale locks: As mentioned above, Yale locks have tailbars. A tailbar is a strip of metal that is attached to the plug and that gets connected to the lock when the lock is fitted. This means that, when you turn the key in the plug, the plug turns with the tailbar, and the tailbar turns the bolt thrower, thereby opening the door.

But it’s just a thin strip of metal attached to the back of the plug by an even thinner piece of metal (basically it’s just a tiny pin). The metal could snap, or the pin could dislodge, thereby disconnecting the plug from the rest of the lock.

Euro cylinders: Instead of having a tailbar, euro cylinders have a so-called cam in the middle. The plug has several small, fiddly connecting pieces that bring it in contact with the cam. Once the key is turned, the connecting pieces turn along with it, and thereby turn the cam which then throws the bolt.

As you can imagine, there’s a lot of scope for dislodged innards in a euro cylinder, especially if it’s old. All it takes is for one of the connecting pieces to fail, and then the chances are the whole cylinder will stop working.

How can I fix it?

Sadly it’s not normally possible to repair this type of problem. The reason is that to get inside the cylinder in order to repair the insides, you need to be able to turn the key. If you can’t use the key, then you can’t really get to the lock without drilling it open and thereby damaging it.

There may be exceptions, but normally it’s not practically possible, even if it’s theoretically possible to, say, replace a tailbar.