A new imitation key often jams when it is first turned in the door lock. This does not necessarily mean that the key does not fit, it just needs to "familiarise" itself a little.

 

It is quite easy to inaugurate the new key by rubbing the tip of a pencil along the teeth of the key. The graphite powder in the pencil helps the key to turn more easily in the lock and acts as a kind of lubricant.