A key that won't turn is one of the most common calls our locksmiths get — and the single most expensive mistake is the one people make in the first thirty seconds: forcing it. A key under strain snaps, and a snapped key turns a fifteen-minute fix into an extraction job and a night locked out. Before you force anything, there is one test that tells you what you are actually dealing with.
Most turning problems come down to one of three things, and you can tell them apart in seconds. Open the door so it is swinging free, take the weight off the hinges, and work the key and handle in mid-air:
Those three outcomes point to three different fixes. Work out which one you have before you touch anything else.
On uPVC and composite doors especially, the door drops a few millimetres on its hinges over time, or moves with the seasons, so the bolts and hooks no longer line up with their keeps in the frame. You will often find yourself lifting the handle harder, or shouldering the door, to get it to lock. Try lifting the handle firmly and straight while turning; a gentle hinge or keep adjustment usually cures it. Don't keep slamming it — every forced lift wears the mechanism toward the failure below.
This is the big one that most guides miss. On a multipoint door, one handle drives a whole row of hooks and bolts through a gearbox behind the handle. When that gearbox wears or breaks, the key can feel stiff, jam halfway, or — the tell-tale sign of the key turns but the door won't open — spin freely without engaging anything at all, because the cam linking the cylinder to the gearbox has sheared. This is not a tweak or a squirt of lubricant; it is a part replacement, and on a locked door it is a job for a locksmith, who can open it without wrecking the door and fit a matching mechanism the same day.
If the handle lifts cleanly but the key itself won't turn, the barrel your key goes into is the suspect — and that points back to the key and the keyway. A key that goes in but won't turn usually means one of a few things:
Puff a little powdered graphite, or a PTFE or silicone spray, into the keyway above the key, then repeat a gentle wiggle-and-turn. Avoid oil-based sprays such as the familiar WD-40: they free things briefly, then attract grime that gums the lock up for good. Never pour anything sticky into a lock.
In a hard frost the lock itself can freeze. Warm the key in your hands or with a hairdryer on a low setting and ease it in slowly — gentle heat, never a naked flame. Resist pouring hot water over the lock or door: on a uPVC frame the sudden temperature change can do more harm than the ice did.
If a key breaks with part of it left in the cylinder, stop — do not push the broken piece in further trying to fish it out, as that drives it deeper. That is now an extraction job, and our guide on a snapped key in the lock explains what happens next.
If the key spins freely, jams even with the door open, or you are starting to force it, that is the moment to stop. If the key turns but the lock no longer moves with it, the cam or mechanism inside has likely failed and will need replacing — something a locksmith can often do while keeping your existing key working on a new matched cylinder. If the stuck key has left you shut out, our locked-out service gets you back in without damage, and our lock changes and repairs page covers the cylinder or mechanism swap. Either way, find your local LocksmithLocal before you force it.
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On a uPVC or composite door this usually means the cam linking the cylinder to the multipoint gearbox has sheared, so the key spins without driving the hooks and bolts. It is a mechanism replacement rather than a DIY fix — stop turning before the key snaps, and if the door is locked shut, call a locksmith who can open it without damage.
Either the door has dropped out of alignment (it works with the door open but fights you when it's shut) or the gearbox is failing (it feels stiff even with the door open). The ten-second open-door test above tells you which: smooth in mid-air means alignment; stiff in mid-air means the mechanism.
Often yes, if the cause is a worn or wrong key, grit in the keyway, or a frozen lock — a spare key and a dry lubricant solve most of those. If the key spins freely or the mechanism jams even with the door open, that is a mechanism fault best left to a locksmith, and forcing it risks snapping the key.
No. Oil-based sprays free a lock for a day, then attract dirt that makes it worse over time. Use dry powdered graphite or a PTFE or silicone spray instead, applied sparingly into the keyway.
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