Top pin

Top pin, “contrapín” in Spanish, is the common name for the upper pin in each chamber of the cylinder, the one that blocks it turning when there is no key. It is the same part many call the driver pin; in the workshop people usually talk about “pins and top pins”.

The difference from the bottom pin lies in its role: the bottom pin reads the key and the top pin, pushed by its spring, acts as a bolt between plug and housing. In a simple cylinder the top pins are usually all the same; what changes the combination is the bottom pins.

In security cylinders the top pins are no longer simple cylinders: they are mushroom shaped, spool shaped or serrated, and they catch if someone tries to manipulate them. They can also be made of steel rather than brass to resist the drill better.

If you are interested in a cylinder with this kind of part, ask about our security cylinders.