Why Keys Break In Locks — And What Not To Try
A key usually snaps because it was already weakened by metal fatigue — years of bending slightly with every turn — not because of one hard twist. Cheap or old cut keys, and worn locks that need extra force to turn, are the two most common reasons a key breaks off inside a cylinder.
The snap always feels sudden, but the weakness was building for a long time before that specific turn.
Why keys actually break
| Cause | Why it leads to a break |
|---|---|
| Metal fatigue from years of use | Repeated flexing weakens the metal at the same point each time |
| A worn or gritty lock needing extra force | More torque on the key concentrates stress at its weakest point |
| A cheap or thin key blank | Less metal to begin with means less fatigue tolerance |
| A key that was already slightly bent | Bent metal fails faster under normal turning force |
What not to do once it snaps
- Do not try to fish it out with pliers or tweezers — this often pushes the broken piece deeper or damages the pins.
- Do not force the lock with the remaining key stub — risks snapping it further or damaging the mechanism.
- Do not use super glue on the broken piece — a common internet suggestion that frequently makes extraction harder, not easier.
How professional extraction works
A broken key extractor tool grips the fragment from inside the cylinder and draws it straight out, typically without damaging the lock. This is a controlled, low-risk process when done with the right tool, unlike DIY attempts with household items.
Does the lock need replacing afterwards?
Usually not. Extraction and a fresh key from the same cut, or a rekey if the old key is a concern, is normally enough. Replacement is only needed if the cylinder itself was damaged during the break or a failed DIY attempt.
Booking a broken key extraction
Tell us where the key broke — a house door, a car ignition, a padlock — since the extraction approach differs slightly. Ranges are on the prices page, full detail on broken key extraction.