What to check first
Try the key alone, without trying to move the bolt at the same time. Does it turn fully and smoothly, or does it bind partway? That separates a cylinder problem from a bolt problem.
Look at the bolt itself if you can see it. Is it visibly rusted, dirty, or does the gate look slightly out of alignment with the frame? Any of those points away from the lock cylinder and toward the bolt or the gate itself.
Do not force the key or spray an unknown lubricant into the cylinder before a provider has looked at it — forcing a jammed lock is the most common way a repairable fault turns into a full lock replacement.
The likely causes, in order
A swollen or corroded bolt (most common). The most common cause is a bolt that has swollen with rust or grime inside its housing, so it physically cannot slide even though the key and lock cylinder both turn normally. HDB's home care guide names this exact fault under its gate topic — how to fix the bolts on your gate if they cannot slot or retract properly — the swollen or corroded bolt described here is one cause of exactly that.
A worn lock cylinder. The second cause is a worn or damaged lock cylinder, where the key turns partway and then binds, rather than turning fully. This is a lock problem, not a bolt problem, and usually means the cylinder needs replacing rather than lubricating.
A sagged or shifted gate. The third cause is a gate that has sagged or shifted slightly, putting the bolt under sideways pressure against its housing so it binds even when the lock mechanism itself is fine.
When to call, and who
Treat this as urgent if the gate is stuck in a position that leaves the home unsecured, or if someone is locked in or out because of it. SPF's guidance is to always close and lock windows and doors when leaving the house or retiring for the night, which assumes the lock actually works — a stuck lock defeats that.
If the gate is stuck closed and locked, with the household otherwise able to get in and out through the main door, this can wait for a normal booking rather than an emergency one.
What it costs
Ask two or three for a written quote instead.
Describe what you found when you ask: whether the key turns fully, whether the bolt is visibly rusted or dirty, and whether the gate looks aligned with the frame. That tells the provider whether to bring a replacement cylinder or expect a bolt and frame job.
Ask whether the quote is for diagnosis plus repair, or diagnosis only with repair quoted separately once the cause is confirmed — a stuck lock sometimes needs opening up before the real fix is clear.
Who to call, and how to judge them
Gate and grille repair does not have a published trade licence to check. Judge a provider on ACRA business registration, a written scope, availability if the issue is urgent, and a business you can verify instead.
NCPC's housebreaking prevention guidance says to "change the lock promptly if the key is lost or stolen" — the same logic applies to a lock that has failed mechanically: replacing a cylinder that will not reliably turn is the safer fix, not persisting with one that half-works.
An ACRA registration confirms the business exists, nothing more. Prefer a provider who asks whether the key or the bolt is the problem before quoting, since the two fixes are not the same job.
Frequently asked questions
Why won't my gate key turn?
A stuck grille gate lock means the bolt will not turn, retract or extend even though the key turns, or the key itself will not turn — usually a mechanical jam rather than the wrong key. The most common cause is a bolt swollen with rust or grime inside its housing.
Is a stuck gate lock urgent?
Treat this as urgent if the gate is stuck in a position that leaves the home unsecured, or if someone is locked in or out because of it. If the gate is stuck closed and locked with the household otherwise able to get in and out, it can wait for a normal booking.
Sources
- HDB, "Gate and Door" home care guide (fetched 15 Sep 2026)
- Singapore Police Force, Housebreaking advisory (fetched 15 Sep 2026)
- National Crime Prevention Council, "House Breaking" (fetched 15 Sep 2026)
Compare gate and grille providers and describe what you found: whether the key turns fully, and whether the bolt looks rusted or misaligned.
