Guide
Anti-Snap Locks, Lock Snapping and How to Check Your Own Door
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Checking Your Cylinder in Thirty Seconds
The quickest useful test happens on your doorstep: see how far the key cylinder stands out from the handle or escutcheon around it, then read what is printed on its face. Nothing needs unscrewing.
Step one: is it a euro cylinder?
Seen from outside, a euro cylinder's keyhole sits in a rounded top with a slimmer section running beneath. Most uPVC, composite and aluminium doors use one, as do a few timber doors. If you have a mortice lock or nightlatch instead, this check may not fit your door.
Step two: flush or proud
Crouch level with the handle and view the cylinder side-on. It might sit snugly against the plate, stick out noticeably, be recessed too far, be shielded by a security handle or escutcheon, or look damaged or misaligned. Handles and doors vary, so there is no universal projection to measure against.
Step three: the markings
On the cylinder, look for a single star or three, a Diamond symbol, a maker's name or other product details. Then look at the handle on its own, where two stars may appear. Those describe the handle only, so note the two sets apart.
Step four: photographs
Capture the cylinder and outside handle together, a side view, each marking, the inside handle or thumbturn, and the locking strip if the door happens to be open. Such pictures let someone confirm the product without taking the lock apart. Do not force, trim or shift the cylinder, and do not remove hardware looking for marks; the box, receipt or original documents may hold what the face does not.
Reading what you found
- Three stars plus a Kitemark on the cylinder: record the manufacturer and verify that exact cylinder.
- A Diamond mark: look up the exact product in the Sold Secure directory.
- One star on the cylinder, two on the handle: both components and both ratings need verifying.
- “Anti-snap” printed but no recognised mark: the security rating stays unverified.
- Nothing visible: go back to the paperwork or have the cylinder identified.
- Noticeable projection: have its size, fit and protection assessed.
Flush and marked is the good outcome; proud and unmarked deserves attention. “Anti-snap” names an intended design rather than a test result, and this check stops short of proving the complete door is secure. What it gives you is a clear list of what to look at next.
Why the Euro Cylinder Is the Weak Point
Below the cam, the euro cylinder contains relatively thin metal. This is a characteristic of its profile and the point its protection must address. A cylinder body can be engineered to fail safely at that point, while protective hardware can keep it inaccessible. Those approaches explain why outwardly similar cylinders may offer different protection.
Two Ways to Reach Three Stars
This matters when assessing euro cylinders in uPVC or composite doors. TS 007 gives star ratings to the cylinder and to the protective handle or cover. The component carrying the mark determines its meaning.
One recognised arrangement combines a Kitemarked one-star cylinder with a two-star security handle or protective cover that is also Kitemarked. The other uses a Kitemarked cylinder rated at three stars, which needs no separate two-star handle to achieve that rating.
Guidance issued by the Door and Hardware Federation sets out both TS 007 routes. Two stars on protective hardware describe its contribution; they do not assign two stars to the cylinder. Correct fitting and the external handle remain important with either arrangement. A cylinder assessment cannot establish how secure the door, frame and locking mechanism are together.
Evidence Behind a Marking
A recognised testing and certification scheme covers products bearing its Kitemark. The correct stars should sit alongside that mark. Treat stars without supporting identification cautiously, as decoration or sales graphics can look official.
Gather the Kitemark information, manufacturer, star total and product particulars before verifying the claimed rating. Check which component each mark belongs to.
Two Schemes That Do Mean Something
Most cylinders that mean something carry one of two marks: a TS 007 star rating or the SS 312 Diamond rating from Sold Secure. They are independent schemes run by different organisations, both recognised for cylinder security, and a single cylinder can hold either, both or neither of them.
TS 007 and Its Star Rating
TS 007 stars should come with a Kitemark. Three on the cylinder means the cylinder reaches the level alone. One on the cylinder means it was designed to be combined with two-star protective hardware.
Sold Secure's SS 312 Diamond
Diamond belongs to a particular cylinder model that passed Sold Secure testing, and the exact model can be checked in the directory.
Where the rating stops
Think of a rating as part of the picture rather than all of it. A cylinder rated highly may protect less when wrongly sized, when it sticks out unnecessarily, or when the door furniture around it is damaged or unsuitable. Check cylinder projection, the amount it extends past the outside handle or protective plate. Sizing should match the door's thickness and hardware, and there is no universal projection figure because handles, plates and cylinder designs vary. A cylinder that appears to project too far may be easier to grip or attack, but appearance alone will not confirm incorrect fitting; accurate measurements are needed first.
The outside handle or escutcheon, the plate protecting the key opening, is another layer worth checking for cracks or impact damage, loose handles or fixings, gaps around the cylinder, a plate that has moved and a cylinder that moves during ordinary use. If inspecting it would mean leaving the door unsecured, leave it fitted.
Inside, some cylinders need a key and some have a thumbturn. Changing type without checking suitability is unwise, particularly for flat entrances, communal doors and fire doors, where safe escape and building requirements can decide the hardware.
Seek an inspection when the cylinder is loose, appears wrongly sized or sits within damaged hardware, or when the key or thumbturn is stiff, the handle unstable or the door impossible to secure reliably. Such signs locate the starting point, not the fault. The key, handle, spindle, multipoint mechanism or door alignment may each be involved, and fitting a new cylinder will not correct poor alignment, so check all of them together.
Anti-Snap Is a Marketing Word and Not a Standard
Sellers can call cylinders anti-snap without certification. What matters is a mark supported by a certification body's testing of the specific product. Product listings and box descriptions need that supporting evidence before their security claims can be relied upon.
Check Identity Before Interpreting Symbols
A diamond, star or Kitemark may not reveal the exact cylinder rating alone. Visually check both ends, leaving everything assembled. Record maker and model, SS 312 Diamond mark, TS 007 star rating and certification or licence number; photograph illegible details.
TS 007 stars may cover protective furniture as well as cylinders. Locate each mark carefully: neither handle nor cylinder ratings establish the other's rating or whole-door certification.
Compare those identifiers, appearance and ratings against Sold Secure's approved lock-cylinder directory. For police-preferred specification products, Secured by Design's product search offers another check. Seek certification-body records or manufacturer technical confirmation. Missing entries can mean older certification, discontinued stock or another product name. Ask the manufacturer or a qualified locksmith about ambiguity; keep unidentified security ratings unconfirmed.
Understand What Was Tested
Sold Secure expresses SS 312 assessments as grades; stars belong to TS 007. Its recognised door-cylinder rating, SS 312 Diamond, is awarded through Sold Secure after that exact model passes testing. Diamond currently leads the cylinder directory's grades. Some cylinders have this and TS 007 three-star, but the ratings are independent.
Sizing and installation still need checking with SS 312 Diamond. That award does not certify the handle or cover, establish multipoint condition or settle insurance requirements for the door. Suitable hardware remains necessary.
What Else Is Worth Doing on the Same Door
Ask what else the door needs before thinking the cylinder settles it. An anti-snap cylinder can strengthen one vulnerable area of the lock, but it is one component in a wider system of handle, multipoint mechanism, hinges, frame and door. Any weak link there can reduce the protection a highly rated cylinder offers, which is why a secure door is judged as a complete system.
The rest of the door, briefly
- The outside handle or escutcheon shields the cylinder, and a rated handle provides one of the two ways to a three-star result.
- The keeps and door alignment decide whether the hooks, rollers and bolts engage fully; the door should close without being lifted, pushed or pulled, and locking should not need excessive pressure on the key or handle.
- The hinges, frame and fixings hold everything in position.
- Glass close to the lock matters where a thumbturn could be reached through it.
What a rated cylinder does and does not cover
A TS 007 or SS 312 rating applies to the product that was tested and does not automatically certify the door, frame or locking system. For example, a three-star cylinder can provide strong protection against attacks aimed at the cylinder but cannot compensate for a damaged handle, loose frame, failed multipoint mechanism or badly fitted door. Some complete doorsets are tested and certified as a system, which differs from fitting a rated cylinder to an existing door.
A suitable cylinder can lose some of its value if it is the wrong length, projects needlessly past the handle, is loose in the mechanism, is fitted beside damaged or unsuitable hardware, or sits in a door that will not close or lock properly. If you are doing a single job, let it be the cylinder, since it is the most self-contained improvement, while remembering that rating, size, installation and hardware have to work together.
What an Upgrade Actually Involves
Upgrading a cylinder is rarely a big job. On most uPVC and composite doors one fixing screw holds the cylinder, and replacing it leaves the door and the multipoint mechanism exactly where they were. That works because a euro cylinder is normally a separate part, so the whole multipoint lock seldom has to change, and because “anti-snap” refers to the cylinder and its protection rather than the mechanism in the door.
| Part | What happens |
|---|---|
| Cylinder | Removed and replaced with a rated one sized to the door |
| Multipoint mechanism and door | Left alone |
| Handle | Kept if secure, undamaged and compatible; replaced only if being upgraded |
Get the measurements before the purchase. A replacement has to match the door and its fitted hardware; each side is measured from the centre of the fixing-screw position to the end, and the inside measurement may not equal the outside one. The inside operation has to be right as well, since some doors have a key on both sides and others a thumbturn. A flat entrance, communal entrance or fire door needs particular care so the doorset still meets its escape requirements.
A cylinder-only swap is often suitable after a lost, stolen or possibly copied key, when the cylinder is worn, damaged, the wrong size or unreliable with a sound key, or when you want a verified rated product, as long as the handle and multipoint mechanism work properly. If the cylinder moves, a loose retaining screw or damaged handle may be to blame, so confirm the cause first.
Some faults sit elsewhere. If the handle will not operate the locking points, the hooks, rollers or bolts are stuck, the door has dropped, the gearbox has failed, the handle or plate is damaged, or the door is insecure despite the key turning, a new cylinder will not help; adjustment or mechanism repair will. A damaged or unsuitable handle also reduces the protection around a rated cylinder, and some recognised arrangements rely on protective handles, so assess all three parts together.
Not Sure What Your Cylinder Is? Ask Us
We will look at what you have, tell you what it is, and quote for a change if that is what you want. Most people only need the first two: a straight answer about the cylinder already in the door.
Worth a call if
The cylinder carries no identifiable rating or maker, projects noticeably, or moves with the handle in normal use. The key catches, is difficult to turn or functions only when held at particular angles. The handle fails to operate all the locking points, or the door locks fine while open but stiffens when closed. The door has dropped, the handle, escutcheon or frame is damaged, a key has gone missing or may have been copied, or someone has attempted a break-in. An inspection can also settle doubts about size or fitting on a cylinder that otherwise looks right. If the door cannot be locked at all, tell us straight away.
What we check, and what to ask
Cylinder type, size, condition and markings; the handle or plate; the multipoint mechanism; how the locking points meet the frame; door and hinge adjustment; and whether a cylinder alone would fix it. Ask which part needs attention and why, and whether it is adjustment, an upgrade, protective hardware or mechanism work.
Useful to have: door material, a photo of the cylinder face and body, whether it is flush or proud, markings, and photos of the handles and door edge.
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Ask What Cylinder You Have: 01424 571056
Alternatively, call or message B.T Locksmiths Hastings from the contact page.
An anti-snap cylinder deserves consideration once its TS 007 or SS 312 rating has been verified, it fits the door correctly and it is paired with suitable protective hardware. Labels can say anything, so we check the markings and the exact product before relying on any security claim. The cylinder is also only one part of the entrance; the handle, multipoint mechanism, hinges, frame and alignment have to stay secure and working.
Anti-Snap Lock Questions
How can I tell if my door lock is anti-snap?
Start with recognised certification when checking the lock’s anti-snap status. For example, look for the three-star level under TS 007 with its Kitemark, or certification at SS 312 Diamond. Without that supporting evidence, the term “anti-snap” cannot establish whether independent tests were carried out.
Does a TS 007 three-star cylinder mean it is anti-snap?
Yes. Verified TS 007 certification at three stars covers resistance tests against snapping and other recognised attack types. To identify the claimed level, check that the cylinder shows the appropriate Kitemark; three stars should accompany it. The answer depends on that rating being verified.
Is SS 312 Diamond better than TS 007 three-star?
No, SS 312 Diamond cannot simply be ranked above TS 007 three-star by its title. They use distinct tests and certification systems. A rating belongs to the particular product tested, so evidence of one is not proof of the other; cylinders can, however, carry both. For the rating scales, SS 312 uses Sold Secure grades and TS 007 uses stars. Each signals enhanced cylinder security, giving stronger support than a bare “anti-snap” claim.
Can I replace the euro cylinder in my uPVC door with an anti-snap cylinder?
It is often possible, as long as the replacement meets the door’s requirements. Both external and internal cylinder measurements must be correct. The euro-profile design must match too, together with the operating arrangement. Ensure the cylinder is compatible with the hardware that is already on the door.
Do I need new handles with an anti-snap cylinder?
The handles only need changing if they cannot meet the required condition and compatibility checks. Undamaged, secure handles that suit the new cylinder can remain. A replacement cylinder is feasible in many cases; it must have the correct euro-profile shape, external and internal dimensions, operating arrangement and compatibility with fitted hardware. Some recognised security arrangements rely on combining a cylinder rated one star with two-star protective handles or with a lock surround.
What if my cylinder has stars but no Kitemark?
Check the official product record before accepting a three-star claim without its Kitemark. Three stars by themselves cannot verify TS 007 certification at three stars. Record the entire marking first, making sure the manufacturer and model checked are the exact ones concerned.
Does an anti-snap cylinder stop every type of break-in?
No, resistance at the cylinder is only part of door security. Anti-snap cylinders are designed to withstand attacks focused on that component, without offering protection from every entry method. The handle and multipoint lock matter too, as do hinges, glazing, the frame and the standard of installation.
Why does my lock work with the door open but not when closed?
The door or its locking points may not line up correctly with the frame. Before choosing a replacement cylinder, check the hinges and the alignment of the latch, bolts and keeps. Changing the cylinder cannot put a misaligned door or its locking points back into alignment.
Should I replace the cylinder after losing a key?
Consider prompt replacement where a lost key might have been copied or could be traced to your property. Changing the cylinder takes away that key’s ability to operate the door. Those possibilities are the reasons to consider a change following the loss.
How often should an anti-snap cylinder be replaced?
Condition and suitability guide the decision, rather than a universal replacement schedule. Arrange inspection or replacement for damage, unreliable operation, incorrect fitting or the effects of an attempted attack. A change in security needs that leaves the cylinder unsuitable is another reason for that attention.