Guide
Anti-Snap Locks, Lock Snapping and How to Check Your Own Door
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Check Your Lock Cylinder in Thirty Seconds
Stand on the outside of the door, level with the handle, and look at the key cylinder. How far it sits beyond the handle or escutcheon, and what is stamped on it, is the whole of this check, and you do not need to take anything apart.
Before you start
This applies to euro cylinders: a keyhole set in a rounded section with a narrower section below it. They are fitted to many uPVC, composite and aluminium doors and to some timber doors. A mortice lock, nightlatch or different locking system may mean this guide does not apply. Remember too that calling a cylinder “anti-snap” states a design aim; it is not proof of any test.
The four looks
- Keyhole side. Confirm the euro profile described above.
- Profile. Viewed from the side of the handle, the cylinder may be close to the surrounding hardware, project noticeably, sit too deeply, be protected by a security handle or escutcheon, or look damaged or incorrectly positioned. Doors differ, so there is no single projection measurement that fits all of them.
- Cylinder face. Look for one star, three stars, a Diamond symbol, a manufacturer name or any other clear product mark.
- Handle. Check it as a separate component. The handle is what two stars or another mark in that position refer to; stars marked on the cylinder refer to the cylinder.
Take photographs as you go: cylinder and outside handle together, the side view, each marking, the inside handle, keyway or thumbturn, and the locking strip if the door is already standing open. They help verify the product without dismantling the lock. Do not push, shorten or reposition the cylinder, or remove any hardware to look for a hidden marking. If the face is blank, the packaging, receipt or product documentation may be the only source.
What it tells you
| You found | Next |
|---|---|
| Three stars and a Kitemark on the cylinder | Record the manufacturer; verify the exact cylinder |
| One star on the cylinder, two stars on the handle | Verify both components and ratings |
| A Diamond marking | Check the exact product in the Sold Secure directory |
| Anti-snap wording only | Treat the rating as unverified |
| No marking | Check documents or ask for identification |
| Noticeable projection | Have size, fit and protection assessed |
Flush and marked: a good position. Proud and unmarked: the result worth doing something about. Either way, the check points to what needs examining next rather than declaring the complete door secure.
The Euro Cylinder: Why It Is the Weak Point
Thin metal in the middle of the euro cylinder, beneath the cam, creates its weak point. The profile makes this a design characteristic rather than a separate fault. Protection comes from a cylinder body made to fail safely there, or hardware that keeps that point beyond reach. Both approaches address the same weakness.
Separate the Cylinder from Its Cover
For uPVC and composite doors using euro cylinders, TS 007 provides star ratings for cylinders and protective handles or covers. Stars must be read on the component that bears them. Two stars on a handle describe that handle's protection, without rating the cylinder at two stars.
Three-star protection has two recognised routes. Use either a Kitemarked three-star cylinder, or a Kitemarked cylinder with one star plus Kitemarked two-star hardware, such as a security handle or cover. The three-star cylinder achieves its rating without a separate handle rated at two stars. These options are explained in the Door and Hardware Federation's TS 007 guidance.
The outside handle and proper fitting still influence security. A cylinder's rating cannot establish the condition or security of the complete door, frame or locking mechanism.
Identify the Certification
The stars should be supported by the Kitemark and show the appropriate number. A product carrying that mark has coverage under a recognised testing and certification scheme. Decorative stars or sales artwork may resemble certification symbols; neither is sufficient evidence alone.
Before verification, collect the maker's name, product particulars, number of stars and Kitemark details. This gives the claim an identifiable basis.
The Two Schemes That Mean Something
A buyer needs to recognise two marks, not one: the TS 007 star rating and SS 312 Diamond, which is published by Sold Secure. Different bodies run them, both are recognised indicators of cylinder security, and you may find a cylinder with one, with both or with neither.
TS 007 and the Star Rating
Look for the stars together with a Kitemark. Three stars on the cylinder itself is a complete rating; one star relies on a two-star handle or cover to reach three-star protection.
Sold Secure and SS 312 Diamond
The Diamond applies to the tested model only, and the Sold Secure directory lists the models that hold it.
The fit behind the rating
A rating is one piece of a larger picture. The same cylinder may give less protection if it is the wrong length, stands out without need, or is housed in damaged or unsuitable door furniture. How far it reaches past the outside handle or plate is called cylinder projection, and the right size depends on door thickness and the hardware fitted. Because handles, protective plates and cylinders vary, there is no single measurement that suits every door. A cylinder that looks too long may be easier to grip or attack; still, looks cannot confirm a wrong fit, and only accurate measurements should drive a replacement.
| Hardware sign | Why it matters |
|---|---|
| Cracks, impact damage, a plate out of place | The escutcheon around the key opening is a protective layer |
| Loose handle, loose fixings, gaps | The cylinder loses support |
| Cylinder moving in normal use | Fit or fixing needs checking |
Do not strip hardware off for a look if that leaves the door unsecured. Swapping a key-both-sides cylinder for a thumbturn type, or the reverse, needs a suitability check, above all on flat entrances, communal doors and fire doors where escape rules 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 are reasons to arrange an inspection. They show where to start rather than which part failed: a stiff key can trace back to the key, handle, spindle, multipoint gearbox or alignment, and changing the cylinder does nothing for a misaligned door.
Anti-Snap Is a Marketing Word and Not a Standard
Using anti-snap as a sales description requires no certification. Trust evidence linking a product mark to certification-body testing of the exact cylinder model. A box or website cannot establish that connection through wording alone.
Follow the Product Details
Examine both cylinder ends without taking anything apart. Record maker, model, licence or certification number, SS 312 Diamond marking and TS 007 stars. Use photographs for small markings. A star, diamond or Kitemark may not be sufficient identification alone.
Compare the installed cylinder's appearance, markings and rating with its entry in Sold Secure's approved lock-cylinder directory. Secured by Design's search supplies an additional check for police-preferred specification products. For confirmation, refer to manufacturer technical details or the relevant certification body. Missing entries can concern renamed or discontinued products or older certification. A manufacturer or qualified locksmith can clarify; unresolved ratings stay unconfirmed.
Keep Ratings in Their Proper Scope
SS 312 grades are awarded by Sold Secure; TS 007 expresses its ratings through stars. Recognised door-cylinder rating SS 312 Diamond is awarded through Sold Secure following successful tests on the exact model. Diamond currently occupies its directory's highest cylinder grade. Some cylinders hold both Diamond and TS 007 three-star, but each rating needs separate verification.
Depending on their location, TS 007 stars may rate cylinders, protective handles or covers. Component ratings cannot transfer or certify whole doors.
An SS 312 Diamond label does not answer questions about door insurance, multipoint condition, cylinder dimensions, installation or independent handle and cover ratings. The cylinder must suit its surrounding hardware and be fitted properly.
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 Upgrading Actually Involves
On most uPVC and composite doors, upgrading means swapping the cylinder, which is held by a single fixing screw. It is not a new door and not a new mechanism: a euro cylinder is normally a separate component, so it can usually be changed without replacing the multipoint lock. That fits the term, since “anti-snap” describes protection in or around the cylinder rather than the locking mechanism inside the door.
Changes
the cylinder, replaced by a rated one sized so it sits close to the handle.
Stays
the multipoint mechanism and the door itself.
Stays unless upgraded
the handle, which can remain if it is secure, undamaged and compatible with the new cylinder.
What changes and what does not
A cylinder-only change suits a lost, stolen or possibly copied key, a worn or damaged cylinder, one an undamaged key no longer works reliably, a wrong-sized cylinder, or a wish to move to a verified rated cylinder, provided the handle and multipoint mechanism still work properly. A cylinder that moves is not always the culprit; a loose retaining screw or damaged handle can cause it, so confirm the cause before buying anything.
Measure before you purchase. The replacement has to match the door and its hardware, euro cylinders are measured from the centre of the fixing-screw position to each end, and the inside and outside lengths may differ. It also needs the right inside operation, a key or a thumbturn. On a flat entrance, communal entrance or fire door, the new cylinder must keep the doorset suitable for its escape requirements.
A new cylinder will not help if the handle no longer drives the locking points, hooks, rollers or bolts are stuck, the door has dropped, the gearbox has failed, the handle or plate is damaged, or the door stays insecure while the key turns. Those need adjustment, hardware repair or mechanism work. A damaged or unsuitable handle can weaken a rated cylinder, and some recognised arrangements depend on a protective handle or escutcheon, so look at the cylinder, handle and lock as one system.
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: 01244 557061
Alternatively, call or message Safe Locksmiths Chester 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?
A recognised security rating is the useful evidence: examples include SS 312 Diamond certification and a TS 007 three-star rating carrying the Kitemark. Treat “anti-snap” as a description unless supported by certification. That wording by itself gives no confirmation of independent cylinder testing.
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 is automatically better in every case. SS 312 Diamond and the TS 007 three-star level are distinct ratings, each tied to the precise product that was tested. They follow different test requirements, with stars used for TS 007 and Sold Secure grades for SS 312. Both support enhanced cylinder security more convincingly than the term “anti-snap”. Products sometimes achieve both certifications; checking one does not, on its own, verify the other.
Can I replace the euro cylinder in my uPVC door with an anti-snap cylinder?
Yes, this is a possible upgrade in many cases, subject to a proper match. The new cylinder must be compatible with the door’s current hardware. It also needs the right euro-profile design, suitable internal and external measurements, and the correct arrangement for operating the lock.
Do I need new handles with an anti-snap cylinder?
Handle replacement depends on their condition and fit with the new cylinder. Secure handles without damage can remain when compatible. An anti-snap cylinder swap is often possible, but requires the correct euro-profile design, internal and external sizing, suitable operation and compatibility with existing hardware. In some recognised security arrangements, the cylinder has one star and is combined with protective handles having two stars, or with 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?
No. Door security also involves the handle, multipoint locking mechanism, hinges, frame and glazing, as well as the quality of installation. An anti-snap cylinder is intended to resist attacks targeting the cylinder itself; its protection does not extend to every possible method of entry.
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?
Think about a prompt cylinder change following the loss. Replacement stops the missing key operating that door. It is worth considering if the key could be connected to your property, and also if there is a possibility that someone has made a copy.
How often should an anti-snap cylinder be replaced?
Anti-snap cylinders do not all need changing after a set period. Have yours inspected or replaced if operation becomes unreliable, damage occurs, the fitting is wrong or an attempted attack has affected it. Changing security needs that make it unsuitable are another reason to act.