The original lever key opened the door yesterday, but today the lock does not accept it

Client name and history details have been changed.

Let's call the client Sergey. In the evening, Sergei came home, opened the door with a regular key, and later closed the lock with the same key. Nothing unusual.

The next morning he tried to open the door. The key was the same. Original. There was no visible damage to it. It fit completely into the keyhole. But it was no longer possible to turn it normally.

The first reaction was bewilderment:

“This is definitely my key. He opened this very door yesterday. Why doesn’t the lock accept him today?”

This situation is indeed possible.

The correct key does not guarantee the functionality of the lock itself

In a lever mechanism, the key must move the internal elements to a strictly defined position. If inside the lock happened:

• wear;
• skew;
• jamming;
• spring damage;
• displacement of parts;
• disruption of lever operation;

even an absolutely correct key may no longer operate the mechanism normally. Outwardly, it looks as if the lock “does not recognize” its own key.

The reason may not even be inside the lock itself

For example, the door leaf sagged a little. The crossbars were pressed against the mating part of the box. Now the mechanism needs to overcome additional load.

Sometimes a person notices that if at the same time:

• push the door a little;
• pull it towards you;
• raise the handle;

the key starts working. This may indicate a problem with the door position or the load on the deadbolts.

Why shouldn't you use force?

The most dangerous reaction: "You just need to turn harder." As a result you can:

• bend the key;
• break the key;
• leave the piece inside the lock;
• additionally damage the internal mechanism.

The original fault then becomes much more complex. If the key previously turned normally, but now you feel stiff resistance, it is better to stop.

What if you try the second key?

This is a useful check. If the second good original key behaves in exactly the same way, the problem is most likely not in one specific key. But even if the second key works, the first one still needs to be carefully checked for wear and deformation.

What will the master do?

The professional task is not to immediately destroy the lock. First, the specialist tries to determine the nature of the malfunction:

• is the lock under load;
• does the door work correctly;
• what position is the mechanism in;
• is it possible to carefully restore movement;
• Is it possible to open the lock without causing serious damage?

Only after opening can you fully assess the condition of the internal elements.

Important early symptom

Often, before the final failure, the lock gives warnings for some time. For example:

• the key has to be wiggled;
• previously one movement was enough, now several are needed;
• the key periodically rests;
• the lock works better at a certain position of the door;
• turning has become noticeably harder.

If such symptoms have already appeared, it is better to check the mechanism while the door is still opening.