Quick answer
A multi-point lock is a single steel mechanism running the height of the door edge, engaged in one motion by lifting the handle, which drives hooks, deadbolts and rollers into keeps on the frame simultaneously. Turning the key afterwards deadlocks the mechanism so it can't be forced back open from either side.
Overview
A multi-point mechanism is a single steel strip running down the door edge. Lifting the handle drives a gearbox that in turn drives hooks, bolts and rollers at multiple points into keeps on the frame. Turning the key deadlocks the mechanism.
The gearbox: the heart of the system
Everything starts with the gearbox, a compact unit set into the door edge roughly at handle height. Lifting the handle rotates a cam inside the gearbox, which pushes a vertical drive bar up and down the door edge. That drive bar is connected to every locking point on the mechanism, so one lift of the handle fires all of them at once - typically five points on a standard residential door, seven on taller or higher-security doors.
The cylinder's job is separate: once the handle has done the work of extending the hooks and bolts, turning the key rotates a cam that engages a pawl in the gearbox, locking the whole drive bar in position so it can't be pushed back by hand or by force from outside.
Hooks, bolts and rollers each do a different job
The three main point types aren't interchangeable in function. Hooks curl into a keep and physically resist the door being pulled or levered outward, which is why they're concentrated near the top and bottom of the door where prising force is most effective for an intruder. Deadbolts are simple shoot bolts that resist being sawn or drilled once the key has engaged them. Anti-lift rollers or blocks stop the whole leaf being jemmied upward off its hinges, a once-common attack on older single-point locks.
- Hooks - resist prising and pulling, usually top and bottom
- Deadbolts - resist sawing and drilling once key-locked
- Rollers/anti-lift blocks - stop the door being lifted off its hinges
Why the handle-lift order matters so much
The design assumes handle first, key second, every time. Lifting the handle takes the mechanical load of extending the hooks and bolts, which is a reasonably heavy action. If someone skips that step and tries to force the key to do both jobs at once - which some people do out of habit from older single-point locks - the load goes through the cylinder cam instead of the gearbox, and that's one of the most common causes of a snapped key or a sheared cam we see in call-outs.
What happens when one point fails
Because the drive bar links every point mechanically, a single broken hook or a bent section of drive bar can affect the whole mechanism - sometimes causing every point to feel stiff, sometimes causing only the affected point to stop moving while the others still work. Either way, a mechanism with even one dead point is operating below its rated security and is worth fixing rather than living with.
Seasonal and coastal wear on the moving parts
The hooks, rollers and drive bar are all steel moving against other steel or against uPVC keeps, and that combination needs regular lubrication to keep working smoothly. In Cornwall's salt-laden coastal air, unlubricated mechanisms corrode and stiffen noticeably faster than the same components would inland, which is why we recommend lock servicing more frequently for properties within a mile or so of the sea.
Spotting a mechanism that's on its way out
A gearbox rarely fails without warning. Increasing stiffness, a handle that needs two hands, a grinding noise as points engage, or a lock that works some days and not others are all early signs worth acting on before the mechanism fails completely and locks you in or out.
Typical repair costs in Cornwall
| Work | Typical price | Notes |
|---|---|---|
| Multi-point lock service & lubrication | £75-£110 | Recommended annually, more often on the coast |
| Gearbox replacement | £180-£280 | Matched to door manufacturer's brand |
| Individual hook or drive bar section replacement | £90-£160 | Where only one point has failed |
Guide prices only — we confirm the cost after seeing the door.
When to call a professional
- If any point fails to engage.
Prevention
- Always lift the handle before turning the key - puts load on the mechanism, not the cylinder.
