When it comes to securing a building, not all door locks are created equal. If you are involved in architecture, construction, or global hardware sourcing, you have likely encountered the term EU mortise lock or euro mortise lock. While they may look similar to their American counterparts at first glance, the differences in design, functionality, and security standards are significant.

There are few things more frustrating than a stuck door handle, especially when you're trying to repair, replace, or re-key a vintage lock. If you are dealing with a mortise door lock, you know that these mechanisms are a bit more complex than the standard cylindrical locks found in modern homes. Their durability and classic aesthetic make them a favorite for homeowners, but that complexity often leads to confusion when it's time to take them apart.