Key

A key is the part that, when you put it into a lock or a lock cylinder, sets the mechanism inside in exactly the right position so that it can turn and open. Every key has cuts or marks that only fit its own lock.

In homes around here the most common are the edge-cut key, with teeth along one edge, and the dimple key, with small dimples on its face. In older houses you still see the large bit key used in lever locks.

If the key starts going in stiffly or is hard to turn, do not force it. On the coast the salty air corrodes lock cylinders from the inside, and a forced key ends up snapping inside the lock. Very often the answer is to change the lock cylinder before it leaves you locked out.