Guide
Anti-Snap Locks, Lock Snapping and How to Check Your Own Door
Call with your postcode for a current arrival estimate.
- 24-hour emergency cover
- No call-out charge
- Price agreed before work starts
Check Your Cylinder in Thirty Seconds
Judge the cylinder with your own eyes before trusting any label on it. The key part on the outside of the door either sits neatly within its handle or stands out beyond it, and it either carries a recognised mark or it does not. You can learn both in under a minute, with the lock left fully assembled.
Run through these four points
- What type is it? The shape of a euro cylinder narrows below the rounded section surrounding its keyway. It is the usual choice on uPVC, composite and aluminium doors and is found on some timber doors. Mortice locks, nightlatches and other systems may not be covered by this guide.
- How does it sit? Seen from the handle side, it will sit close to the surrounding hardware, project noticeably, sit too deeply, be protected by a security handle or escutcheon, or appear damaged or wrongly placed. No one projection measurement is correct for every door.
- What is on the cylinder? Stars (one or three), a Diamond symbol, a manufacturer name, other clear marks.
- What is on the handle? Treat it as its own item: two stars or another marking may be there, and they apply to the handle alone.
Keep the two sets of markings in separate notes. Avoid pushing, shortening or moving the cylinder, and do not remove the hardware to find a hidden mark; some information exists only on the packaging, the receipt or the original documents. Photograph the cylinder with the outside handle, the cylinder from the side, every mark, the inside handle, keyway or thumbturn, and the locking strip if the door is already open, so the product can be checked without dismantling.
Matching the result to a next step
Three stars with a Kitemark on the cylinder: record the manufacturer and verify the exact cylinder. A Diamond mark on the cylinder: check the exact product in the Sold Secure directory. Where the cylinder bears one star and the handle or escutcheon bears two, check each component and its rating. The word “anti-snap” with no recognised mark: consider the rating unverified, since a description is not a test. For an unmarked cylinder, consult the original documents or request identification of the cylinder. Noticeable projection: have the size, fit and surrounding protection assessed.
Flush and marked is reassuring; proud and blank is the one to address. The check does not confirm the whole door is secure, but it tells you which parts to look at next.
Why the Euro Cylinder Is the Weak Point
Metal below the cam is thin in a euro cylinder, leaving a weak section at the centre. That section belongs to the profile's design, so effective protection must account for it. The choices are a cylinder body that fails safely at that point or protective hardware that prevents it being reached from outside.
Compare the Recognised Arrangements
When euro cylinders are fitted to uPVC or composite doors, both the cylinder and surrounding hardware matter. TS 007 awards stars to cylinders, protective handles and covers, with the meaning depending on the marked component.
The Door and Hardware Federation explains two ways of attaining the three-star level under TS 007. A Kitemarked three-star cylinder qualifies independently, without requiring a separate two-star handle for its rating. The combined route requires a one-star cylinder and a two-star security handle or protective cover, each Kitemarked.
A handle's two-star marking applies to its protection around the cylinder, not to the cylinder's own rating. Suitable external hardware and correct installation remain necessary considerations. Stars on a cylinder cannot confirm the security of its door, frame or locking mechanism.
Look for Supporting Identification
For evidence of recognised testing and certification coverage, check the Kitemark. It should have the relevant star number beside it. A star count without that context is inadequate, especially where decorative symbols or marketing artwork resemble official marks.
Note the manufacturer and precise product details, together with the Kitemark and stars, before investigating the claim. Keep track of which item carries each rating.
Anti-Snap Is a Marketing Word, Not a Standard
No certification is required for a seller's anti-snap description. Trust markings supported by a certification body's testing of the exact model. Listing titles and packaging alone cannot demonstrate that independent approval.
Read Each Claim Separately
TS 007 provides star ratings, while Sold Secure supplies SS 312 grades. Sold Secure awards recognised door-cylinder rating SS 312 Diamond after testing the exact model successfully. Its highest current cylinder grade is Diamond. Some products achieve both that and TS 007 three-star; they remain separate awards, without either proving the other.
TS 007 stars may identify a cylinder rating or one for protective door furniture. Check their location. A handle mark cannot rate the cylinder, and cylinder certification cannot establish handle or whole-door certification.
Confirm the Product Behind the Mark
Symbols alone, including a Kitemark, star or diamond, may not establish a precise rating. Read both ends without dismantling, noting certification or licence references, maker and model, the SS 312 Diamond mark and any TS 007 stars. Photograph small lettering.
Search Sold Secure's approved cylinder directory, comparing identification, appearance and rating. For products with police-preferred specification, another checking resource is the Secured by Design product search. Seek confirmation using the manufacturer's technical information or certification-body records. Absence can reflect discontinued products, older certificates or different names. Ask the manufacturer or a qualified locksmith; unmatchable ratings remain unconfirmed.
Even with SS 312 Diamond, inspect multipoint condition and check the door's insurance requirements. The award does not guarantee a correctly sized or fitted cylinder, or a separately rated handle or cover. Choose compatible hardware.
The Two Schemes That Mean Something
The two schemes a UK buyer is likely to meet on a cylinder are TS 007, shown as a star rating, and SS 312 Diamond, which Sold Secure publishes. Each is a recognised indicator of cylinder security, each is managed by a separate organisation, and any given cylinder might have one mark, both or none.
TS 007 and Its Star Rating
TS 007 marks come with a Kitemark. A three-star cylinder meets the level on its own, while a one-star cylinder reaches it only alongside a two-star protective handle or surround.
Sold Secure's SS 312 Diamond
Diamond applies to the specific cylinder model Sold Secure tested, and that model should appear in its published directory.
Why fit matters as much as the mark
A security rating tells only part of the story. A well-rated cylinder may protect less if it is incorrectly sized, protrudes unnecessarily or is paired with damaged or unsuitable handles. The distance it extends beyond the outside handle or protective plate is known as cylinder projection, and the cylinder ought to suit the thickness of the door and its fittings. No single projection measurement fits every door, because hardware and cylinder designs differ. One that appears to stick out too far may be easier to grip or attack, but looks alone cannot confirm it is wrongly fitted, which is why accurate measurements are needed before choosing a replacement.
The outside handle or escutcheon (the protective plate around the keyhole) gives another layer. Signs worth noting: - cracks, impact marks or a plate knocked out of position - loose handles, loose fixings or gaps around the cylinder - a cylinder that shifts during normal use
Leave the hardware in place if taking it off would leave the door unsecured. Inside, some cylinders use a key and some a thumbturn; changing between them needs checking first, especially on flat entrances, communal doors and fire doors, where escape and building requirements apply. A loose or wrongly sized cylinder, damaged hardware, a stiff key or thumbturn, an unstable handle or a door that will not lock reliably all call for an inspection. None of these identifies the exact fault, since the key, spindle, multipoint mechanism or door alignment could be responsible, and replacing the cylinder will not correct poor alignment. Treat them as a reason to check the cylinder, handle and locking system together.
What an Upgrade Actually Involves
The honest scale of an upgrade on most uPVC and composite doors: one screw, one cylinder, and the rest of the door left alone. A euro cylinder is usually a stand-alone component that can commonly be replaced without touching the multipoint lock, and “anti-snap” refers only to protection in or around that cylinder, not to the mechanism within the door.
The cylinder is exchanged
for a rated one, sized so it sits flush with the handle rather than proud.
The multipoint mechanism and door stay
exactly as they are.
The handle stays
if it is secure, undamaged and compatible, unless you are upgrading it as well.
Here is what that means in practice:
Measure before buying anything. The replacement has to match the door and the hardware on it; euro cylinders are measured from the centre of the fixing-screw position to each end, and inside and outside can be different lengths. Get the inside operation right too, a key on both sides or an internal thumbturn. Flat entrances, communal entrances and fire doors deserve extra care, so that the doorset continues to meet its escape requirements.
A swap alone is often enough when a key has been lost or stolen or might have been copied, when the cylinder is worn, damaged or wrongly sized, when an undamaged key will not operate it reliably, or when you want a verified security-rated cylinder, as long as the handle and multipoint mechanism are working correctly. A moving cylinder is not proof it needs replacing, since a loose retaining screw or damaged handle can be the cause; confirm that before purchase.
A cylinder will not fix a handle that does not operate the locking points, hooks, rollers or bolts that remain stuck, a door that has dropped or become misaligned, a failed multipoint gearbox, a damaged handle or protective plate, or a door that stays insecure when the key turns. Those need adjustment, repair or work on the wider mechanism. Some recognised security arrangements also depend on a protective handle or escutcheon, and a damaged handle reduces a rated cylinder's protection, so treat the cylinder, handle and lock as one decision.
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.
Ask Us What Your Cylinder Is
Ask HD Locksmiths Bournemouth what your cylinder is and you will get an answer, not a sales pitch: we read the markings, identify the product and give a price for changing it only if you want that.
Useful details to share
- door material
- a photo of the cylinder face and the body
- whether it sits flush with the handle or proud of it
- any visible lock markings and photos of the handles and door edge
- the problem you have noticed, and whether the property can be secured at present
Times when an inspection makes sense
When the rating cannot be verified, the lock no longer works reliably, or the door cannot be secured properly. More specifically: a cylinder with no identifiable rating or manufacturer; noticeable projection beyond the handle; a cylinder or handle that moves; a key that sticks, turns poorly or needs a certain angle; a handle that misses locking points; a door that is stiff only when closed or has dropped; visible damage to the handle, escutcheon or frame; a lost, stolen or possibly copied key; or a door affected by an attempted break-in. It can be useful where the cylinder looks suitable but its fit is uncertain. If the entrance cannot be locked, say so when you ask for help.
The inspection takes in the cylinder's type, size, condition and certification marks, the handle or protective plate, the multipoint mechanism, how the locking points meet the frame, whether the door or hinges need adjustment, and whether a cylinder change alone would solve the problem. Ask for an explanation of which component requires attention and the reason, along with whether the proposed solution involves adjustment, upgrading the cylinder, protective hardware or work on the wider mechanism.
For an anti-snap cylinder to be worth considering, it needs a verified TS 007 or SS 312 rating, a correct fit and suitable protective hardware to work with. The label does not prove that; the markings and exact product do. Keep in mind that the handle, mechanism, hinges, frame and alignment must stay secure as well. There is no call-out charge at any hour, emergency calls are taken around the clock all year, and the price is set out on the call.
Ask What Cylinder You Have: 01202 935089
Or call or message HD Locksmiths Bournemouth if that suits you better.
Anti-Snap Lock Questions
How can I tell if my door lock is anti-snap?
A Kitemark for a TS 007 rating of three stars, or SS 312 Diamond certification, is the sort of recognised evidence to seek. Marketing wording is less conclusive: calling a cylinder “anti-snap” does not demonstrate that it has been tested independently.
Does a TS 007 three-star cylinder mean it is anti-snap?
Yes. A cylinder with verified certification at the three-star level of TS 007 has been tested against snapping and other recognised attack techniques. Look at the cylinder itself: it should show three stars accompanied by the relevant Kitemark as part of that rating.
Is SS 312 Diamond better than TS 007 three-star?
A name alone cannot settle which rating is better. Some cylinders hold both TS 007 three-star certification and the SS 312 Diamond rating, but these remain separate systems with different testing requirements. SS 312 is graded through Sold Secure, and TS 007 is rated using stars. Either is evidence of enhanced security, stronger than “anti-snap” wording by itself. Ratings cover the exact products tested, so having one must not be taken as automatic confirmation of the other.
Can I replace the euro cylinder in my uPVC door with an anti-snap cylinder?
In many cases, the euro cylinder can be changed for an anti-snap model. Suitability depends on more than its security description: the replacement needs the correct euro-profile shape and the right inside and outside measurements. Its operating configuration must also match, with compatibility across the existing door hardware.
Do I need new handles with an anti-snap cylinder?
Existing handles may be suitable, so replacement is not automatic. They must be secure and undamaged, as well as compatible with the cylinder being fitted. For some recognised arrangements, a lock surround or two-star protective handles accompany a one-star cylinder. Changing the cylinder is often possible, but its euro-profile design, external and internal measurements, operation and compatibility with the door hardware must be correct.
What if my cylinder has stars but no Kitemark?
Stars alone cannot verify the rating. For TS 007 at three stars, the relevant Kitemark is needed as well. Note down every part of the marking, then check an official product record for the precise manufacturer and model to establish what certification applies.
Does an anti-snap cylinder stop every type of break-in?
No, fitting an anti-snap cylinder cannot cover all possible routes of entry. Its design addresses attacks directed at the cylinder. Security is also influenced by how well the door is installed and by its multipoint lock, handle, glazing, hinges and frame.
Why does my lock work with the door open but not when closed?
The locking points, or the door as a whole, could be out of line with the frame. Start by checking the hinges, keeps, latch and bolts. These checks belong before cylinder replacement, because a different cylinder cannot remedy the underlying alignment problem.
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?
The timing depends on the cylinder, with no replacement interval applying to all anti-snap models. Arrange for inspection or replacement following damage, unreliable operation, an incorrect fit or an attempted attack that affects it. A cylinder unsuited to your security needs also warrants that attention.