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.
Why the Euro Cylinder Is the Weak Point
The cylinder is the one part of a uPVC or composite door lock that sits on the outside face, within reach of anyone at the door. That exposure is a fixed feature of the euro profile, so the protection has to come from one of two places: a cylinder designed to keep the lock working if its exposed part is damaged, or protective hardware around it. Ratings show which you have.
How TS 007 Stars Share the Job
TS 007 uses stars to rate a door cylinder and the protective handle or cover around it. Because both components can be rated, the number of stars means something different depending on where the marking sits.
| Marking | Where you may find it | What it means |
|---|---|---|
| One star | Cylinder | Needs a two-star handle or protective cover to make up the recognised three-star combination |
| Two stars | Security handle or protective cover | Protects the cylinder and can be paired with a one-star cylinder |
| Three stars | Cylinder | Reaches the three-star level by itself |
There are therefore two routes to the same level. A Kitemarked three-star cylinder gets there without a separate two-star handle for that rating, although the outside handle and correct fitting still matter, and the cylinder's rating says nothing about whether the door, frame or locking mechanism as a whole is secure. Alternatively, a Kitemarked one-star cylinder can be combined with a Kitemarked two-star security handle or protective cover:
One-star cylinder + two-star protective hardware = three-star protection
The stars have to sit on the right components. A handle’s two-star rating does not give the cylinder a two-star rating.
What the Kitemark Adds
The stars should appear with a Kitemark, which shows that the product is covered by the certification scheme. The Kitemark helps show that the product is covered by a recognised testing and certification scheme, and it ought to be accompanied by the correct number of stars. Stars on their own are not enough to go on, because decorative symbols and marketing graphics can look very like official markings. Record the Kitemark, number of stars, manufacturer and product details before verifying the claim. The Door and Hardware Federation’s guidance on TS 007 explains the two recognised ways to reach the three-star level.
Anti-Snap: A Marketing Word, Not a Standard
A seller can describe a cylinder as anti-snap without certifying it. The useful evidence is a marking tied to that product's certification-body testing. Treat the product description as sales text until the exact model and its independently tested rating can be identified.
Find Out What the Mark Covers
Start at both cylinder ends without removing or dismantling anything. Note the manufacturer, model, certification or licence reference, TS 007 star rating and SS 312 Diamond mark. Photos help with tiny lettering. A lone Kitemark, star or diamond may not identify the precise rating.
Stars under TS 007 may describe protective door furniture or cylinders. Assess the marked component: neither a handle rating nor a cylinder rating certifies the other or the whole door.
Search Sold Secure's approved lock-cylinder directory and compare the recorded details, appearance and rating. Secured by Design offers a product search for checking police-preferred specification claims. Confirm uncertain identities through manufacturer technical information, certification records or a qualified locksmith; unmatched claims remain unconfirmed. Directory absence alone is inconclusive: discontinued products, different names and older certificates can explain it.
Know the Separate Ratings
TS 007 expresses ratings in stars, whereas SS 312 uses grades from Sold Secure. Recognised cylinder rating SS 312 Diamond follows successful testing of the exact model through Sold Secure; Diamond is currently its directory's highest cylinder grade. Some cylinders also hold TS 007 three-star, but neither rating implies the other.
SS 312 Diamond does not verify size, installation, hardware ratings, multipoint condition or whole-door insurance requirements. Correct fitting and suitable hardware remain necessary.
What Upgrading Actually Involves
Think one screw, not a new door. For most uPVC and composite doors, upgrading is a matter of releasing the cylinder's fixing screw, withdrawing the old cylinder and fitting a rated one, with the multipoint mechanism untouched. As a euro cylinder is generally a separate component, its replacement often leaves the rest of the multipoint lock unchanged. Bear in mind that “anti-snap” covers the cylinder and what surrounds it, not the locking mechanism inside the door.
What is touched, and what is not
- The cylinder is replaced and sized to sit flush with the handle.
- The door and multipoint mechanism remain in place.
- The handle remains too, unless you are upgrading it at the same time.
Sizing comes before buying
A new cylinder has to match the door and the hardware already fitted. Measure from the centre of the fixing-screw position to each end; the internal and external lengths can be different. Confirm the inside operation, either a key or a thumbturn. For a flat entrance, communal entrance or fire door, check that the replacement keeps the doorset suitable for escape.
Is a cylinder swap the right fix?
It often is when a key may be lost, stolen or copied, when the cylinder is worn, damaged or the wrong size, when a good key no longer works reliably, or when you are moving to a verified rated cylinder, provided the handle and multipoint mechanism are working. A moving cylinder may only need its retaining screw or handle sorted, so pin down the cause before buying.
It is unlikely to help where the handle does not throw the locking points, hooks, rollers or bolts are stuck, the door has dropped or misaligned, the gearbox has failed, the handle or protective plate is damaged, or the key turns yet the door stays insecure. Those point to adjustment, hardware repair or mechanism work. A sound, compatible handle can stay, but a damaged one reduces protection, and some recognised arrangements depend on a protective handle or escutcheon. The assessment should take account of the cylinder, handle and locking system as a whole.
The Two Schemes That Do Mean Something
TS 007 and SS 312 Diamond are the two names to know. TS 007 grades cylinders and protective hardware with stars; SS 312 Diamond is the Sold Secure rating for security cylinders. They are separate schemes from separate bodies, both recognised, and a cylinder might bear one, both, or neither of them.
TS 007: The Star Rating
A Kitemark should accompany the stars. Three stars on the cylinder meet the level by themselves; one star needs a two-star handle or protective cover beside it.
SS 312 Diamond and Sold Secure
Sold Secure awards Diamond to a specific cylinder model after testing, and lists approved products in its directory.
Fit, hardware and the limits of a mark
No rating covers everything. Fit the wrong size, leave it protruding unnecessarily, or set it in damaged or unsuitable furniture, and a highly rated cylinder may protect less. Projection, sometimes called cylinder projection, is how far it extends beyond the outside handle or protective plate. A correctly sized cylinder suits the thickness of the door and its hardware, but there is no single projection measurement for all doors, since handles, plates and designs differ. When one appears to stick out too far it may be easier to grip or attack, yet appearance cannot by itself confirm a bad fit, and accurate measurements must come before choosing a replacement.
The escutcheon, which is the protective plate surrounding the key opening, and the handle provide another layer. Cracks, impact damage, loose fixings, gaps around the cylinder, a displaced plate or a cylinder that moves in normal use are all worth noting. Do not remove hardware to inspect it if the door would then be left unsecured.
Cylinders may be keyed on both sides or have a thumbturn on the inside. Check suitability before changing from one to the other, particularly on flat entrances, communal doors and fire doors, where safe escape and building requirements can shape the right hardware.
Get the door inspected if the cylinder is loose, seems wrongly sized or sits in damaged hardware, or if the key or thumbturn is stiff, the handle unstable, or the door hard to secure. These signs do not name the fault. A stiff key may involve the key, handle, spindle, multipoint mechanism or alignment, and a new cylinder will not fix a door that has dropped; the cylinder, handle and wider locking system should be checked together.
What Else Is Worth Doing to the Same Door
Once the cylinder is right, the hardware around it is where the remaining protection sits. An anti-snap cylinder is an important improvement to one vulnerable part, yet it works alongside the handle, the multipoint mechanism, hinges, frame and the door itself, and it does not make the complete door secure by itself. A weak point in any of those can reduce what a highly rated cylinder delivers.
What to check alongside it 1. The cylinder's fit within the handle, and the handle or protective plate itself: the plate covers the cylinder, and a rated handle is one of the routes to three stars. 2. The multipoint locking strip, gearbox, and the hooks, rollers and bolts with their frame keeps; the locking points should engage fully without excessive pressure on key or handle. 3. Hinges and door alignment, so the door closes without being lifted, pushed or pulled, plus the frame and its fixings. 4. Any glazed panel close to the lock, especially near a thumbturn.
Whatever the mark, a TS 007 or SS 312 rating applies to the product that was tested. That rating does not automatically extend to the door, frame or locking system. A three-star cylinder may protect strongly against attacks on the cylinder, but it cannot compensate for a damaged handle, a loose frame, a failed multipoint mechanism or a door that was badly fitted. Some complete doorsets are certified as a system, and that is different from fitting a rated cylinder to a door you already have.
Reduced protection is possible from a suitable cylinder that is the wrong length, projects past the handle unnecessarily, is loose in the mechanism, sits beside damaged or unsuitable hardware, or is in a door that does not close or lock correctly. Assess the whole door; if you can only do one thing, start with the cylinder, then let rating, size, installation and hardware work together.
Ask Us Which Cylinder You Have
Send us a description or a photograph and we will tell you what cylinder you have, what its markings mean, and what a change would cost if you want one. That is the whole offer: identification first, a quote only on request.
It helps to know what counts: a cylinder sold as anti-snap earns consideration when its TS 007 or SS 312 rating is verified, it fits the door properly and it works with suitable protective hardware. The wording on the packaging is not enough by itself, which is why the exact product matters, and the cylinder is only one part of the entrance alongside the handle, multipoint mechanism, hinges, frame and alignment.
Reasons people ask us - no identifiable rating or manufacturer on the cylinder - the cylinder stands noticeably proud of the handle - the cylinder or handle moves during normal use - a key that sticks, turns poorly or needs a particular angle - a handle that does not operate all the locking points, or a door that is fine open but stiff when shut - a dropped door, visible damage to handle, escutcheon or frame, a lost or copied key, or an attempted break-in
An inspection can also help when the cylinder looks suitable but its size, fitting or surrounding hardware raises doubts. If the property cannot be secured right now, tell us when you get in touch.
What to have to hand: the door material, a clear photo of the cylinder face and body, whether it sits flush or proud, the visible markings, and photos of the handles and door edge.
When we look, we cover the cylinder's type, size, condition and markings, the handle or plate, the multipoint mechanism, how the locking points meet the frame, any door or hinge adjustment, and whether a cylinder alone would solve it. Ask us which part needs attention and why, and whether that means adjustment, an upgrade, new protective hardware or mechanism work. There is never a call-out charge, emergency calls are taken around the clock every day of the year, and you get a price on the call.
Ask What Cylinder You Have: 01928 611001
You can also call or message Eds Locksmiths Runcorn with your photos.
Anti-Snap Lock Questions
How can I tell if my door lock is anti-snap?
Check for independent certification, including a Kitemark at the TS 007 three-star level or certification to SS 312 Diamond. These are recognised ratings to look for when identifying an anti-snap cylinder. A description that merely calls the lock “anti-snap” does not establish that independent testing has taken place.
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 universal advantage follows just from the rating’s name. Both certifications offer evidence of enhanced cylinder security beyond an “anti-snap” description, but SS 312 Diamond is separate from TS 007 three-star. The systems have different test requirements: TS 007 has star levels, while SS 312 has Sold Secure grades. Only the exact product tested is covered by its rating. Although some products carry both, certification under either system does not automatically demonstrate certification under the other.
Can I replace the euro cylinder in my uPVC door with an anti-snap cylinder?
An anti-snap cylinder can often replace the existing euro cylinder. Before choosing one, establish the required operating arrangement and check compatibility with the hardware on the door. The replacement must also have the correct euro-profile design, with dimensions suited to both the internal and external sides.
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?
You cannot confirm TS 007 at three stars merely by counting stars where the relevant Kitemark is absent. Write out the whole marking, then consult an official product record for a check of the exact manufacturer and model. Use those details to verify the claim.
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 door may be sitting out of alignment with its frame, or the locking points may be out of position. Inspect the bolts and keeps as well as the latch and hinges before changing the cylinder. A replacement cylinder leaves an alignment problem unresolved.
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?
There is no standard period after which every anti-snap cylinder must be replaced. Instead, organise an inspection or replacement when it is damaged, poorly fitted, unreliable or affected by an attempted attack. Take the same step if your security needs now require something different.