Broken Key in the Lock: What to Do (and Not Do)

A key snapping inside a lock is one of the most common urgent calls we get at the workshop in Lidcombe. It usually happens on a key that has been bending for months, on a lock that has been getting stiffer, or when someone forces a key that is not turning. The good news is that a broken key can almost always be removed, and in many cases the lock is fine afterwards. The bad news is that a few well-meant attempts at fixing it yourself can turn a short job into a lock replacement.

This guide explains what to do in the first few minutes, what not to do, how a locksmith removes the broken piece, and how to stop it happening again.

Stop turning, stop pushing

The moment you feel the key give way, stop. Do not try to turn the remaining stub with pliers, and do not push the broken piece back in.

Here is why. Inside a pin-tumbler cylinder, small spring-loaded pins sit along the keyway. A whole key lifts them to the right height. A broken piece of key is now sitting under those pins, held by spring pressure. Every time you push it, it can slide further in and wedge more tightly. Every time you try to turn it, you risk bending the cam or damaging the pins.

If part of the key is still sticking out and you can grip it squarely with your fingers, a gentle straight pull is fine. If it does not come out easily, leave it.

Things that make it worse

We see the results of these attempts regularly:

• Superglue on the broken end. Glue runs into the keyway and sets the pins solid. That lock usually ends up being replaced.
• Hairpins, paper clips and small screwdrivers. These push the fragment further in and scratch the keyway.
• General-purpose spray lubricants. They can help a stuck key slide out, but they also attract dust and gum up the pins later. If you lubricate a lock, use a dry graphite or PTFE lock lubricant.
• Inserting the other half of the key. It is tempting to line up the two pieces and turn, but it puts both pieces under strain and can jam the cylinder.
• Forcing the door. If the lock is locked and the key is stuck, forcing the door damages the frame and the bolt.

Is the door open or locked?

This decides how urgent the job is.

The door is open

If the key broke while the door was open, you can still secure the house in the short term with other locks, or stay home until the lock is sorted. This can often be booked as planned work rather than an urgent call-out.

The door is locked and it is the only way in

Now it is a lockout. Check other doors and spare key holders first. If there is no other way in, call. Our guide to being locked out in Lidcombe covers what to expect, including the ID we need.

The key broke in the deadbolt with the door locked from inside

If you are inside and cannot unlock the door to get out, there is a safety issue. If there is any risk, such as a fire, call 000. Otherwise call us, and keep another exit available.

How a locksmith removes a broken key

We use purpose-made extractor tools that are thin enough to slip alongside the broken piece, hook it and draw it out without disturbing the pins. The process is usually quick when the fragment has not been pushed in further or glued.

Sometimes the cylinder needs to be removed from the door and the key extracted on the bench. In the workshop, this is often simpler, because we can work on the cylinder from the back.

After extraction we:

1. inspect the keyway and pins for damage;
2. test the lock with a good key;
3. cut a replacement key if the broken one was your only copy;
4. tell you whether the lock needs any further attention.

Why the key broke

Keys rarely break for no reason. The common causes are:

A worn or bent key

Keys used daily for years thin out at the neck, the narrow part just past the bow. A key that has been bent and straightened again is especially weak. If your spare looks noticeably newer than the one you use, use the spare and retire the old one.

A copy of a copy

Each time a key is copied from another copy rather than from the original code, small errors build up. A poor copy needs more force to turn, and force is what snaps keys.

A stiff lock

The most common cause. A lock that needs effort to turn is putting stress on every key used in it. Stiffness usually comes from:

• a door that has moved, so the bolt drags on the strike plate;
• dirt and old lubricant in the cylinder;
• worn pins.

The first is very common in older Lidcombe houses where timber doors swell in wet weather. See lock repair.

Using the key as a handle

Pulling a door shut by the key, or hanging a heavy key ring off it, bends the key over time.

Does the lock need replacing afterwards?

Usually not. If the fragment comes out cleanly and the lock turns smoothly with a good key, it can stay. We recommend repair or replacement if:

• the pins or keyway were damaged, often by glue or tools;
• the lock was already worn and stiff;
• the cam or tailpiece was bent by forcing;
• you want to change the key anyway because copies were lost.

If the key was lost or stolen as well, think about rekeying so the missing keys stop working.

Preventing the next broken key

• Replace worn keys. Ask for a new key cut to code where possible, rather than copying a worn key.
• Fix stiff locks early. If you have to lift, push or pull the door to turn the key, the lock or the door needs adjusting.
• Do not force a key. If it does not turn, stop, check you have the right key, and try gently again.
• Keep key rings light. A heavy bunch swinging from the key in the lock strains both.
• Use the right lubricant. A small amount of dry graphite or PTFE lubricant once or twice a year is enough for most locks.

Snapped keys in shops and offices

Commercial locks get far more daily use than home locks, so keys wear faster. If staff are struggling with a lock, it is a warning sign. A broken key in a shopfront at closing time can mean an unsecured shop. See commercial locksmith.

What it costs

Broken key extraction is usually one of the shorter jobs we do, provided the fragment has not been glued or pushed deep. The price goes up if the cylinder has to be removed, if the lock is damaged, or if a replacement is needed. You get a price range on the phone and a fixed price on site before we start. Our locksmith cost guide explains the factors.

Call us

If you have a broken key in a lock in Lidcombe, Auburn, Berala, Regents Park, Homebush or Strathfield, call 02 4503 6922. We are open 7 days, 7:00 AM to 12:00 AM. If the door is open and the job can wait, you can also request a quote. Read more about our emergency locksmith service.