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
Checking Your Cylinder in Thirty Seconds
Look at the outside of your door before you read anything about lock ratings. The cylinder, its position against the handle and the markings on its face tell you most of what you need, and checking them means removing nothing. A product called “anti-snap” is built to resist a particular attack, yet that wording proves nothing about how it was tested.
| Step | Where to look | What to note |
|---|---|---|
| 1 | The outside keyhole | A rounded keyway section with a narrower part below is a euro cylinder |
| 2 | Side-on to the handle | Close fit, noticeable projection, sitting too deep, covered by a security handle or escutcheon, or damaged |
| 3 | The cylinder face | One or three stars, a Diamond symbol, the manufacturer, other product marks |
| 4 | The handle or surround | Two stars or another mark, recorded separately |
Euro cylinders are widely used on uPVC, composite and aluminium doors, and some timber doors have them; if yours has a mortice lock or nightlatch, this may not apply. Projection is judged by eye, because no single measurement suits every door. A star on the handle belongs to the handle, never to the cylinder.
Hands off the hardware: avoid pushing, shortening or repositioning the cylinder, and resist removing fittings in search of a mark. The packaging, receipt or original documents might hold the details instead. Photograph the cylinder alongside its outside handle, its profile from the side, every marking, the inside handle, keyway or thumbturn, and the locking strip if the door is open anyway. Someone can then help identify the product with the lock intact.
Your result - Kitemark with three stars on the cylinder: write down the manufacturer and verify that exact cylinder. - Diamond marking: the exact product should be checked in the Sold Secure directory. - One-star cylinder, two-star handle or escutcheon: verify both pieces and both ratings. - “Anti-snap” and nothing recognised: the rating is unverified. - Blank face: look at the original documents or have the cylinder identified. - Noticeable projection: get the size, fit and protection around it assessed.
A cylinder sitting flush with a genuine mark is the outcome you hope for, while a proud cylinder with no mark is the one to deal with. The check cannot confirm the full door is secure, but it narrows down what to look at next.
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.
Anti-Snap Is a Marketing Word and Not a Standard
Anti-snap is freely used sales wording, not certification. A reliable claim connects a product marking with testing of that exact model by a certification body. Packaging and online descriptions cannot establish that connection themselves. Check the evidence behind the term before choosing a cylinder.
Distinguish the Schemes
TS 007 awards stars; SS 312 uses Sold Secure grades. SS 312 Diamond is recognised for door cylinders and awarded through Sold Secure after the exact model passes testing. Diamond currently tops its cylinder directory. It is separate from TS 007 three-star: some cylinders hold both, but neither proves the other.
Match the Evidence
A star, diamond or Kitemark alone may not establish an exact rating. Without dismantling, inspect both cylinder ends; record maker, model, TS 007 stars, SS 312 Diamond marking and certification or licence number. Photograph unclear details. TS 007 stars may concern cylinders or protective furniture; handle and cylinder ratings are not interchangeable.
Search the Sold Secure approved cylinder directory using those details. Compare identification, appearance and rating. Secured by Design's product search also helps check products awarded its police-preferred specification. Missing entries can reflect discontinued models, alternative names or older certificates. Seek manufacturer or qualified locksmith clarification; leave unmatched claims unconfirmed. Where possible, consult certification records or manufacturer technical information.
SS 312 Diamond does not establish correct sizing, installation, separately rated handles or covers, multipoint condition or whole-door insurance compliance. A rated cylinder still needs suitable surrounding hardware and proper fitting.
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.
The Two Schemes That Do Mean Something
Two marks on a cylinder are worth recognising: TS 007, which rates in stars, and SS 312 Diamond, published by Sold Secure. Both are recognised measures of cylinder security, they are run by different bodies, and a cylinder may carry one, both or neither. Neither is presented here as better than the other.
TS 007 and the Star Rating
Stars appear alongside a Kitemark. Three stars on the cylinder reach the top level alone; one star on the cylinder needs a two-star handle or cover to make the same level.
Sold Secure and SS 312 Diamond
A Diamond mark is awarded to the exact cylinder model that passed Sold Secure's tests, and it can be looked up in their directory.
A rating is only part of the picture
Even a highly rated cylinder can offer less protection if it is the wrong size, sticks out further than it needs to, or sits in damaged or unsuitable door furniture. Check how far it extends past the outside handle or plate, which is called cylinder projection. It should be sized to the door's thickness and its hardware, but handles, plates and cylinder designs vary too much for one projection figure to apply everywhere. A cylinder that looks too long may be easier to grip or attack, yet appearance cannot prove a poor fit; accurate measurements come before any replacement. The escutcheon, the protective plate around the key opening, adds its own layer, so look for cracks, impact damage, loose fixings, gaps around the cylinder, a plate that has shifted or a cylinder that moves in use, without removing anything that would leave the door unsecured. Some cylinders take a key on both sides and others have a thumbturn; do not switch type without checking suitability, especially on flat entrances, communal doors and fire doors where safe escape matters. A loose, oversized or poorly housed cylinder, a stiff key or thumbturn, an unstable handle or a door that will not secure reliably all justify an inspection. Those signs do not pinpoint the fault: a stiff key could be the key, handle, spindle, multipoint mechanism or door alignment, and a new cylinder will not cure a misaligned door. They mean the cylinder, handle and locking system should be checked together. For the full standards picture, see what BS 3621, TS 007 and insurance approved really mean.
What Else Is Worth Doing to the Same Door
Treat the door as a system rather than a single lock. A good anti-snap cylinder improves one vulnerable part, but the protection it gives depends on the handle, multipoint mechanism, hinges, frame and door around it, and a weak spot in any of them can cut into the benefit of a highly rated cylinder.
Handle and escutcheon
the plate covers the cylinder, and a rated handle is one of the two ways to reach three stars.
Keeps and alignment
a door that needs lifting, pushing or pulling to close, or locking points that need force on the key or handle, is not fully protected by anything fitted to it.
Hinges, frame and its fixings
a door that has dropped or a frame that moves weakens the lock's position.
Nearby glazing
a glazed panel close to a thumbturn deserves a mention.
Four places to look next
Ratings are specific. A TS 007 or SS 312 rating applies to the product that was tested, not automatically to the complete door, frame or locking system. A three-star cylinder may offer strong protection against attacks aimed at it, but it cannot compensate for a damaged handle, loose frame, failed multipoint mechanism or poorly fitted door. A doorset tested and certified as a complete system is a separate category from an existing door with a rated cylinder added.
The right cylinder can still under-perform when it is the wrong length, stands out past the handle without need, is loose within the mechanism, is fitted beside damaged or unsuitable hardware, or is in a door that does not close or lock correctly. Should you do one thing only, make it the cylinder, then work outwards: rating, size, installation and hardware all have to work together.
Ask Us Which Cylinder You Have
The simplest next step is to let someone read the cylinder for you. Describe it or send a photo, and we will say what it is, what its markings mean and, only if you want it, what replacing it would cost.
Have this ready
The door material; a photograph of the cylinder face and body; whether the cylinder sits flush or proud; any markings; photos of the handles and door edge; and a short description of the problem. Tell us too whether the property can be secured right now.
When it is worth getting it looked at
- you cannot match the cylinder to a rating or manufacturer
- it sticks out noticeably beyond the outside handle
- the cylinder or handle moves when you use it
- the key sticks, turns poorly or only works at an angle
- the handle does not operate all the locking points
- the door is fine when open but stiff when closed, or has dropped
- the handle, escutcheon or frame is damaged
- a key is lost, stolen or may have been copied, or there has been an attempted break-in
A look can be worthwhile even where the cylinder seems suitable but its size, fit or hardware is in doubt. During an inspection we check the cylinder's type, size, condition and certification marks, the handle or protective plate, the multipoint mechanism, how the locking points meet the frame, any door or hinge adjustment needed, and whether a new cylinder alone would do. You should be told which component needs attention and why, and whether that means adjustment, an upgrade, new protective hardware or wider mechanism work.
Three things make an anti-snap cylinder worth considering: a verified TS 007 or SS 312 rating, a correct fit for the door, and suitable protective hardware working with it. A label is not proof, and the handle, multipoint mechanism, hinges, frame and alignment must stay sound. There is no call-out charge whatever the hour, emergency calls are taken day and night all year, and the price is given on the call.
Ask What Cylinder You Have: 01252 493213
You are welcome to call or message Wilds Locksmiths Farnborough instead.
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, that verified rating includes testing against snapping. A TS 007 cylinder certified at three stars is also tested for other recognised forms of attack. Its marking should combine the relevant Kitemark and three stars on the cylinder, reflecting the certification level.
Is SS 312 Diamond better than TS 007 three-star?
There is no universal ranking between these separate ratings. Enhanced cylinder security is indicated by both SS 312 Diamond and TS 007 at three stars, and either provides better evidence than the description “anti-snap” alone. Their test requirements are different: Sold Secure grades apply within SS 312, whereas TS 007 employs stars. Certification relates to the exact tested product. Some products earn both ratings, but either one by itself cannot establish that the other is held.
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?
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?
Three stars are insufficient evidence of TS 007 three-star certification if the appropriate Kitemark is missing. Copy the marking in full and use an official product record to check the exact model and its manufacturer. The star symbols by themselves do not establish that rating.
Does an anti-snap cylinder stop every type of break-in?
No, its protection is aimed at attacks on the cylinder. It cannot cover every way of gaining entry. Consider the rest of the door too: the glazing and frame, hinges, multipoint lock and handle all affect security, as does how well everything has been installed.
Why does my lock work with the door open but not when closed?
A possible explanation is that the door or locking points are misaligned relative to the frame. Cylinder replacement will not fix that mismatch. Before replacing it, examine the hinges along with the latch, bolts and keeps to check how the door and locking points align.
Should I replace the cylinder after losing a key?
Consider having the cylinder replaced promptly if someone could connect the missing key with your property, or if it might have been copied. A change stops that lost key from operating the door, removing its continued use in that lock.
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.