
Why Keys Break — and What It Means for Your Lock or Ignition
Keys are cut from brass or nickel-silver blanks that gradually weaken at their narrowest points through repeated bending stress. Every time a key enters a stiff lock — a sticky door knob lock on an older home, a mortise lock cylinder that has not been lubricated in years, or a car ignition that requires firm turning — micro-fractures form along the blade. Eventually those fractures reach a tipping point and the key snaps, almost always at the shoulder or at a deep cut in the blade profile where the metal is thinnest.
The lock type matters enormously for what happens next. In a pin-tumbler door knob lock, the broken fragment usually rests near the shear line and can be coaxed out without disassembly if the right extractor hook reaches it. A mortise lock presents a more complex cylinder and a longer barrel, which may require partial disassembly to retrieve the fragment cleanly. Vehicle ignitions are their own category: the fragment is inside a barrel surrounded by a steering column shroud, and the ignition must remain in the correct rotational position to avoid triggering the steering column lock. Our technicians are trained in all three scenarios and carry the specialized hooks, spiral extractors, and pick-style tools matched to each lock family.
