Guide
Anti-Snap Locks, Lock Snapping and How to Check Your Own Door
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Checking Your Cylinder in Thirty Seconds
Here is the check in a sentence: go outside, see whether the key cylinder sits flush with the handle or sticks out past it, and look for a recognised mark on its face. A cylinder described as “anti-snap” is designed to resist one kind of attack, but the phrase cannot tell you how the product was tested, which is why the marks matter. Nothing has to be removed or dismantled.
Four steps at the door
- Find the euro cylinder. Its keyway sits in a rounded section, with a narrower section below. Expect one on many uPVC, composite and aluminium doors, and on some timber doors. This guide may not be applicable if a mortice lock, a nightlatch or a different system is fitted to your door.
- Check the projection. Look from the side of the outside handle. Is the cylinder close to the hardware, noticeably sticking out, set too deep, covered by a security handle or escutcheon, or damaged or out of position? There is no projection measurement that applies to every door, so compare it with the hardware around it.
- Read the cylinder. One or three stars, a Diamond symbol, a manufacturer name and other clear product markings are what to look for.
- Read the handle on its own. Two stars or another mark may appear there. The handle's stars indicate its own rating, while the cylinder's stars indicate the cylinder's rating.
Write the markings down in two separate lists. Do not push, shorten or reposition the cylinder, and do not take hardware off just to find a marking; the packaging, receipt or original documents may carry it instead. Photograph the cylinder together with the outside handle, a side view, every marking, the inside handle, keyway or thumbturn, and the metal locking strip if the door is already open. With those, the product can often be verified or identified while the lock stays in place.
Reading the result
- Three stars and a Kitemark on the cylinder: record the manufacturer, then verify the exact cylinder.
- One star on the cylinder plus two stars on the handle or escutcheon: verify both components and both ratings.
- A Diamond marking: check the exact product in the Sold Secure directory.
- Anti-snap wording, no recognised mark: treat the rating as unverified.
- No marking: check the original paperwork, or ask for the cylinder to be identified.
- Noticeable projection: have its size, fit and surrounding protection assessed.
Flush with a mark is the result you want, and proud with no mark is the case worth doing something about. The check does not confirm the complete door is secure; it shows what to examine next. If the door needs work, our uPVC and composite door lock work page explains what is involved.
The Euro Cylinder: Why It Is the Weak Point
A euro cylinder has a narrow section of metal below its cam, creating an inherent weakness in the profile. The cylinder body must defend that section through a design that fails safely, or protective hardware must prevent access to it. This is the reason protection involves more than choosing a cylinder of the right shape.
Read the Rating in Context
On uPVC and composite doors, the euro cylinder and its surrounding hardware need considering together. Under TS 007, stars assess cylinders as well as protective handles and covers. Their meaning changes with their location.
For a cylinder, three stars with a Kitemark establish the three-star level without requiring a two-star handle for that rating. The alternative pairs a Kitemarked cylinder carrying one star with a Kitemarked security handle or cover carrying two. That combination also reaches the recognised three-star level. A two-star handle contributes protection around the cylinder; its rating cannot be transferred to the cylinder itself.
These are the two recognised arrangements explained by the Door and Hardware Federation in guidance about TS 007.
Establish What Has Been Certified
Look for the Kitemark beside the star count that should accompany it. It signals a recognised testing and certification scheme covering the product. Promotional symbols and decorative stars can resemble genuine markings, so counting stars alone is insufficient.
Log product details and the manufacturer alongside the Kitemark and star number before verification. Even a correctly rated cylinder needs proper fitting and suitable external hardware. Its rating cannot certify the security of the door, frame or complete locking mechanism.
Anti-Snap: A Marketing Word, Not a Standard
Sellers can freely describe cylinders as anti-snap without certifying them. A dependable claim requires product markings backed by certification-body tests on that exact model. Treat packaging advertising or listings as something to verify against that evidence.
Separate Stars from Grades
Sold Secure awards the recognised door-cylinder rating SS 312 Diamond once the specified model passes its tests. The cylinder directory from Sold Secure currently places Diamond above its other grades. SS 312 employs Sold Secure grades, while TS 007 assigns stars. Some models carry TS 007 three-star alongside SS 312 Diamond, but these are independent ratings; evidence for either cannot establish the other.
Neither size, installation, handle or cover certification, multipoint condition nor complete-door insurance compliance is confirmed by Diamond. It does not replace correct fitting or suitable surrounding hardware.
Build an Identifiable Record
Without an identifiable certification record, isolated symbols such as a Kitemark, diamond or star may not settle the rating. Inspect both cylinder ends without dismantling. Capture manufacturer, model, TS 007 stars, SS 312 Diamond marking and certification or licence reference; photograph difficult lettering.
TS 007 stars may belong to protective furniture or cylinders. Identify which: a rating cannot transfer between components or certify the entire door.
Search the Sold Secure approved cylinder directory; match appearance, recorded details and rating. Use Secured by Design's product search for police-preferred specification checks. Verify through certification bodies or manufacturer technical information where possible. Directory omissions can reflect older certificates, discontinued models or alternative names. Have the manufacturer or a qualified locksmith resolve uncertainty; otherwise leave the rating unconfirmed.
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.
What Else Is Worth Doing to the Same Door
After the cylinder, the next question is the door it sits in. An anti-snap cylinder can strengthen one vulnerable point, but it cannot secure the door alone, because it depends on the handle, multipoint mechanism, hinges, frame and door around it. A weakness in any of these reduces what a highly rated cylinder can do, and a secure door should be looked at as a complete system.
Things worth doing on the same door | What | The reason | |---|---| | Rated handle or escutcheon | It covers the cylinder and is one route to a three-star result | | Keeps and alignment | Hooks, rollers and bolts should engage fully without excess pressure, and the door should close without lifting, pushing or pulling | | Hinges, frame and fixings | A dropped door or moving frame weakens every lock fitted | | Glazing beside the lock | A thumbturn within reach of glass changes the picture |
Also check the locking strip and gearbox. Keep ratings in proportion: a TS 007 or SS 312 rating applies to the product that was tested, and it does not certify the complete door, frame or locking system. A three-star cylinder can provide strong protection against attacks aimed at the cylinder; it 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 is not the same as putting a rated cylinder into an existing door.
A suitable cylinder may still offer reduced protection when it is the wrong length, projects beyond the handle unnecessarily, is loose in the locking mechanism, sits next to damaged or unsuitable hardware, or is installed in a door that does not close or lock correctly. Where only one job is being done, do the cylinder first; it is the most self-contained change. Its rating, size, installation and surrounding hardware must then all work together.
What Upgrading Really Involves
Expect a smaller job than you might think. On the majority of uPVC and composite doors, the cylinder comes out after one fixing screw is released and a rated cylinder goes in; the door and the multipoint mechanism are left as they are. Euro cylinders are generally separate parts, which is why the full multipoint lock rarely needs changing, and “anti-snap” refers to the cylinder and the protection around it, not the mechanism within the door.
The job in three lines 1. Out: the existing cylinder. 2. In: a rated cylinder, sized to sit close to the handle rather than standing proud. 3. Untouched: the multipoint lock and the door, plus the handle unless you choose to upgrade it too.
Measurement comes first, because the cylinder must match both door and fitted hardware. Each end is measured from the centre of the fixing-screw position, and the two sides are often different lengths. The inside operation matters as well: key on both sides, or thumbturn. Take extra care on a flat entrance, communal entrance or fire door, where the result must still suit the doorset and its escape needs.
Changing only the cylinder can be the right answer when a key is lost, stolen or may have been copied, when the cylinder is worn, damaged, wrongly sized or unreliable with a good key, or when you want a verified rating, as long as the handle and multipoint mechanism work correctly. Movement in the cylinder can come from a loose retaining screw or damaged handle instead, so establish the cause before ordering a part.
It will not solve a handle that fails to work the locking points, jammed hooks, rollers or bolts, a dropped or misaligned door, a failed gearbox, a damaged handle or plate, or a door that stays insecure although the key turns. Those call for adjustment or repair of the wider mechanism. Your existing handle can stay if it is secure, undamaged and compatible, but a poor one reduces the protection around a rated cylinder, and some recognised set-ups rely on protective handles. Measuring and fitting are covered in how a replacement lock is measured and fitted.
Ask Us Which Cylinder You Have
Whatever the check showed, we can tell you what it means. Describe the cylinder or send a photo, and we will read the markings, identify what is fitted and quote for an upgrade if you want one; nothing is assumed about what your door needs.
The anti-snap cylinders worth considering are those with a verified TS 007 or SS 312 rating that fit the door correctly and work with suitable protective hardware. The words on a label are not enough, so the exact product is what we check, and because the cylinder is only one part of the entrance, the handle, multipoint mechanism, hinges, frame and door alignment need to be sound as well.
What helps us help you: the door material, a photo of the cylinder face and body, whether it sits flush or proud, any markings, pictures of the handles and door edge, the problem you have noticed, and whether the property can currently be secured. If it cannot, make that the first thing you say.
Worth raising with us 1. No identifiable rating or manufacturer on the cylinder. 2. Noticeable protrusion of the cylinder past the external handle. 3. The cylinder or handle shifting during everyday use. 4. A key that catches, resists turning or functions only when positioned at particular angles. 5. A handle that does not operate all the locking points, or a door that is stiff only when closed. 6. A dropped door, or damage to the handle, escutcheon or frame. 7. A lost, stolen or possibly copied key, or an attempted break-in.
Even if the cylinder appears suitable, concerns about its dimensions, installation or hardware make an inspection useful. We look at the cylinder's type, size, condition and markings, the handle or plate, the multipoint mechanism, how the locking points meet the frame, whether the door or hinges need adjusting, and whether a cylinder alone would fix things. Ask which component needs attention and why, and what kind of work is being recommended. There is no call-out charge at any time of day, emergency calls are answered every day of the year, and the price is given on the call.
Ask What Cylinder You Have: 01977 210006
Photos ready? Call or message J.K Locksmiths Castleford.
Anti-Snap Lock Questions
How can I tell if my door lock is anti-snap?
Certification provides a clearer answer than the words “anti-snap”. Look for SS 312 Diamond or a three-star TS 007 rating with the Kitemark. Both are recognised examples of ratings to check. An anti-snap claim, without supporting certification, cannot confirm that the cylinder underwent independent tests.
Does a TS 007 three-star cylinder mean it is anti-snap?
Yes, provided the TS 007 three-star rating is verified. It means the cylinder has undergone tests for resistance to snapping as well as other recognised forms of attack. The cylinder should carry the appropriate Kitemark alongside three stars; the verified rating supports the anti-snap claim.
Is SS 312 Diamond better than TS 007 three-star?
Neither name establishes an overall winner. TS 007 expresses its ratings in stars; SS 312 follows the grading system used by Sold Secure. Their testing requirements differ, so SS 312 Diamond and the three-star TS 007 rating are separate certifications. Both indicate enhanced security and are more informative than “anti-snap” wording alone. Check the exact tested product: certification under one system does not automatically confirm the other, although some products hold both.
Can I replace the euro cylinder in my uPVC door with an anti-snap cylinder?
Yes, many uPVC doors allow this cylinder upgrade. A suitable replacement must have a matching euro-profile design and the appropriate measurements for each side, inside and outside. Check how it operates as well: the operating arrangement and its compatibility with existing hardware both need to be right.
Do I need new handles with an anti-snap cylinder?
Keep the existing handles if they are secure, free from damage and suitable for the new cylinder. In many cases an anti-snap cylinder can be fitted, but it must have the right euro-profile shape, dimensions on both sides and operating configuration, while matching the installed door hardware. Handle protection also features in some recognised arrangements: these use a cylinder with one star alongside protective handles at two stars or a lock surround.
What if my cylinder has stars but no Kitemark?
Do not treat three stars without the relevant Kitemark as confirmation of TS 007 three-star status. Identify the exact manufacturer and model using the complete marking you have recorded, and compare those details with an official product record. That provides a basis for checking the claimed certification.
Does an anti-snap cylinder stop every type of break-in?
It helps resist cylinder attacks, but it cannot prevent every type of entry. Include the frame, handle, glazing, multipoint lock and hinges when considering door security. How well the door has been fitted matters too, alongside the resistance offered by the cylinder itself.
Why does my lock work with the door open but not when closed?
Poor alignment between the frame and either the door or its locking points may explain this. Review the hinges first, together with the latch, keeps and bolts, before replacing the cylinder. An alignment fault needs addressing because changing the cylinder cannot correct it.
Should I replace the cylinder after losing a key?
A cylinder replacement will make the lost key unusable on that door. If copying is a possibility, or the missing key could be associated with your property, consider having the cylinder changed promptly. These are reasons to assess replacement after losing a key.
How often should an anti-snap cylinder be replaced?
Replacement is not governed by a fixed interval for all anti-snap cylinders. Arrange a check or a replacement if the cylinder has damage, operates unreliably, is incorrectly fitted or has been affected by an attempted attack. Its suitability for your present security needs is also a reason for inspection or replacement.