Why Do Keys Break? Common Causes and How to Prevent It
A broken key can happen without warning. One moment you are unlocking your front door, and the next half of your key is stuck in the lock. While it may seem like bad luck, keys usually break for a reason.
At Eastern Bays Mobile Locksmiths, we regularly help homeowners and businesses across Auckland with broken keys, jammed locks and emergency lockouts. Understanding why keys break can help you avoid expensive repairs and inconvenient lockouts.
Why do keys break?
Keys are made from relatively soft metals such as brass or nickel silver. They are designed to wear before the internal components of the lock do. Over time, repeated use, metal fatigue and additional stress can weaken a key until it eventually snaps.
What are the most common reasons keys break?
1. The key has worn out
Every time you insert and turn a key, tiny amounts of metal wear away. After years of daily use, the key becomes thinner and weaker, making it much easier to snap.
Signs of wear include:
- Rounded or shiny edges.
- The key feels loose in the lock.
- The key occasionally sticks.
- The key requires extra movement to work.
2. The lock is stiff
If a lock is dirty, worn or poorly aligned, more force is needed to turn the key. The extra pressure is transferred directly to the weakest point of the key.
A locksmith can usually service the lock before the key breaks.
3. The door is out of alignment
Doors naturally move over time due to weather, humidity and building movement. When the latch or deadbolt no longer lines up correctly with the strike plate, people often force the key to turn.
The problem is often the door rather than the key.
4. The key has been bent
Many people carry keys in their pocket, toolbox or handbag where they are bent or twisted. Even a slight bend weakens the metal and increases the chance of snapping.
5. Using the wrong key
If a similar-looking key is forced into the wrong lock, it can become jammed and break. Never force a key that does not insert or turn smoothly.
6. Extreme force
Keys are designed to turn locks—not act as levers. Excessive force, particularly on older locks, is one of the leading causes of broken keys.
Can cold weather cause a key to break?
Yes. While Auckland rarely experiences freezing temperatures, colder weather can make metal slightly less flexible. Combined with a stiff lock, an already worn key is more likely to snap.
Can modern keys still break?
Yes. Traditional house keys, restricted security keys, mailbox keys and even some vehicle keys can all break if they become worn or if the lock develops a fault.
What should I do if my key breaks in the lock?
Do not try to force the remaining piece further into the lock.
You should:
- Leave the broken piece where it is.
- Avoid using glue or homemade extraction tools.
- Do not insert another key.
- Call a qualified locksmith.
In many cases, a locksmith can remove the broken key without replacing the lock.
Can a broken key damage the lock?
Yes. If someone attempts to remove the broken piece using incorrect tools, the internal pins, springs or cylinder can become damaged, making a simple repair much more expensive.
How can I stop my keys from breaking?
- Replace worn keys before they become too thin.
- Have stiff locks serviced regularly.
- Fix doors that are difficult to close or lock.
- Avoid twisting or bending keys.
- Never force a key that does not turn easily.
- Keep locks clean and properly lubricated with products suitable for locks.
Should I copy an old worn key?
No. A locksmith should always copy a good-quality original key whenever possible. Copying a worn key simply reproduces the wear, which can lead to ongoing problems with the lock.
When should I call a locksmith?
You should contact a locksmith if:
- Your key is difficult to turn.
- The lock feels rough or sticky.
- Your door needs lifting to lock.
- Your key has visible wear.
- Your key has bent.
- Your key has already broken.
Eastern Bays Mobile Locksmiths can help
If your key has broken or your lock is becoming difficult to use, it is often far cheaper to repair the problem before the key snaps completely.
Eastern Bays Mobile Locksmiths provide professional mobile locksmith services throughout the Eastern Bays and greater Auckland, including broken key extraction, lock servicing, rekeying, lock repairs, replacement locks and emergency lockout assistance.
If your locks are becoming difficult to operate, contact Eastern Bays Mobile Locksmiths before a worn key leaves you locked out.
Frequently Asked Questions
Why do house keys suddenly snap?
Keys usually do not break suddenly. They weaken over many years through normal use until the metal eventually fatigues.
Can a locksmith remove a broken key without replacing the lock?
Yes. In many cases, a locksmith can extract the broken key while leaving the existing lock intact.
Is it cheaper to replace a worn key than repair a broken lock?
Absolutely. Replacing a worn key is inexpensive compared with repairing or replacing a damaged lock after a key breaks.
Should I lubricate my locks?
Yes. Using the correct lock lubricant helps reduce wear and keeps the lock operating smoothly. Avoid using products that attract dirt and dust.
Can old locks cause keys to break?
Yes. Worn internal components, poor alignment and increased friction place additional stress on the key every time it is used.
