Why Keys Snap — and What Happens Inside the Lock
Keys break for a predictable set of reasons: metal fatigue from years of daily use, applying sideways force while the bolt is still under tension, a worn-out lock cylinder that forces you to wiggle harder than you should, or the simple shock of a dropped key ring that bends the blade just enough to create a stress fracture. The break usually happens at the bow-to-blade junction or at the first set of cuts — the thinnest cross-section on any key blank.
Once a fragment is inside the cylinder, the situation can go one of two ways. If the fragment is flush with or protruding past the keyway face, an experienced technician has relatively straightforward access. If it has slid deeper into the plug — especially in a tight mortise lock keyway common in older Emerson apartment buildings and brick-and-mortar commercial storefronts along Kinderkamack Road — extraction requires slender professional tools that can grip the serrated edge without pushing the piece further in. Attempting removal with a bobby pin or thin screwdriver almost always makes the fragment migrate deeper, sometimes to the point where the entire cylinder must be replaced rather than repaired.
