Remove a broken key from a lock

Take out a broken key stuck in a lock using simple tools, then test and lubricate the lock.

RK-01Stop and check the key positionDo not keep turning or wiggling the key once it snaps. This can push the broken piece deeper or jam the pins. Look at how much of the key is visible in the cylinder — if a decent length is sticking out, you may not need any special tools.

RK-02Gather the right toolsYou want fine tools, not brute force. A pair of needle-nose pliers or fine tweezers, a proper key extractor set, and a junior hacksaw blade cover most cases. Keep a lock lubricant and a spare key blank nearby too, in case you need them later.

1 each · Needle-nose pliers

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1 set · Key extractor set

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1 each · Junior hacksaw blade

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RK-03Try pliers or tweezers firstIf enough of the key is showing to get a grip, grasp it firmly with the pliers or tweezers and pull it straight out. Pull in a dead straight line, in the same direction the key normally comes out. Do not twist as you pull, or the fragment can jam sideways.

RK-04Use a key extractor for a flush breakIf the broken end is flush with the lock face, slide the thin hooked tool from the extractor set in alongside the key blade, with the hook facing the cuts. Gently work it past the fragment, then rotate slightly so the hook catches a notch, and draw it out. Take your time — rushing this step is what causes fragments to slip further in.

RK-05Try the hacksaw blade method if that failsSnap off a short length of junior hacksaw blade, about 20mm, teeth facing outward. Slide it in alongside the broken key so the teeth catch under the key's serrations, then pull both out together. Wear a glove or hold the blade with pliers, since a snapped edge can be sharp.

1 each · Junior hacksaw blade

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RK-06Use superglue only as a last resortIf nothing else has worked, cut a spare key blank down to a short stub and put a tiny drop of superglue on its tip only. Push it against the broken key's end, hold still for a few seconds, then pull straight out immediately — do not let it fully cure. This risks gluing the pins inside the cylinder, so only try it on a lock you're prepared to replace if it goes wrong.

1 tube · Superglue (cyanoacrylate)

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1 each · Spare key blank

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RK-07Test and lubricate the lockOnce the fragment is out, test the lock with a working key several times, checking it turns smoothly with no grinding. Apply a light squirt of graphite or PTFE-based lock lubricant into the keyway — never oil, which attracts grit and gums up the pins over time.

1 can · PTFE or graphite lock lubricant

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RK-08Replace the cylinder if the lock still won't turn properlyIf the key kept snapping, the lock feels stiff, or you couldn't get the fragment out, the cylinder itself may be worn or damaged. A euro cylinder is a straightforward swap on most uPVC and composite doors — undo the single retaining screw on the door edge and slide the old cylinder out. If the door is a front door or on an escape route, get a locksmith to check it, since fitting the wrong cylinder length can affect how securely the door locks.

RULES

1 each · Replacement euro cylinder lock

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KNOW THE RULES

If this is a front door or a fire escape route door, get advice before changing the lock — Building Regulations require final exit doors to open easily from inside in an emergency.

RK-09Tidy upWipe away any metal filings or glue residue from the lock face and surrounding door. Dispose of the broken key and hacksaw offcut safely, wrapped so no one is cut handling the bin bag. Give the lock one more test before you consider the job finished.

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