Guide
Anti-Snap Locks, Lock Snapping and How to Check Your Own Door
Questions about a cylinder? Call 01483 377197, any hour of any day.
Go to your front door and look at the keyhole from outside: if the cylinder stands out beyond the handle on a uPVC or composite door, that is the part this guide is about. Lock snapping is aimed at the euro cylinder, the replaceable barrel the key goes into, and specifically at a cylinder that is exposed.
The word "anti-snap" on a product listing tells you what a seller intends, not what has been tested. Two certification schemes do carry real weight, and this guide from Woking Locksmith shows you how to recognise both, how to check the door you already have, and what a genuine upgrade involves.
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Check Your Cylinder in Thirty Seconds
The quickest test needs no tools: stand outside, look at the cylinder, and see how far it reaches past the handle or the escutcheon (the plate around the keyhole). Many uPVC, composite and aluminium doors have replaceable euro cylinders; these are the main focus of this guide.
Go outside.
Look at the key side of the door rather than the inside thumbturn or key.
Look at how it sits.
Is the face of the cylinder level with the handle plate, or does it stand proud of it?
If it stands proud, measure it.
Use a ruler, a tape or a coin for scale. The Crime Prevention Website observes that on some doors a cylinder sticks out from the door surface by as much as 10mm.
Look for a marking.
Check the cylinder face and the visible part of its body for stars or a diamond symbol. A mark is the only evidence of certification; if you are not sure what kind of lock you have at all, our guide to identifying door lock types will help.
Three stars beside a «Kitemark»
write down the manufacturer, then verify that exact cylinder.
A Diamond symbol
look up the exact product in the «Sold Secure» directory.
The four-step check
What you find tells you what to do next:
Reading the result: a cylinder that sits flush and carries a recognised mark is in good order. A cylinder that stands proud and carries no marking is the one worth acting on.
A protective handle or cover around the cylinder can add to what the cylinder alone provides, so note that too. For uPVC door lock work, your measurement is the first thing a locksmith will ask for.
Why the Euro Cylinder Is the Weak Point
The metal at the centre of a euro cylinder, just below the cam that drives the lock, is thin, and the Crime Prevention Website identifies that as the weak point. Because the narrowing is built into the profile, the answer is either a cylinder designed to fail safely at that point or hardware that keeps the cylinder out of reach.
Where the Weakness Sits in the Cylinder
The euro profile narrows in the middle, around the cam, and this is a feature of the shape rather than a fault in manufacture. A cylinder designed with that in mind answers it in layers:
- A sacrificial section built to break in a controlled place, so that the part left in the door still operates the lock.
- Hardened inserts and pins inside the body that resist drilling.
- Pin designs that resist other approaches, which is why a certified cylinder is tested against several things together rather than one.
This explains how two cylinders that look identical on a shelf can differ in price by a factor of three, and why the marking counts for more than the product description. If you are thinking about having a cylinder replaced, ask what the marking is before you ask what it costs.
Why This Is a uPVC and Composite Door Subject
To be clear about scope: this is a euro cylinder issue, so it concerns uPVC, composite and aluminium doors and largely passes by a timber door secured with a mortice lock.
- Applies: doors with a euro cylinder, which covers most uPVC, composite and aluminium entrance doors.
- Largely does not apply: timber doors with a mortice lock, which have no euro cylinder and whose security is judged against a different standard.
uPVC and composite doors are widely fitted to UK homes, so a cylinder question is relevant to a large share of households rather than a niche. The section on schemes below explains what to look for.
That is why the «TS 007» scheme rates two things: the door cylinder and the protective handle or cover that surrounds it. Its stars carry a different meaning depending on where you find them:
| Marking | Usually found on | What it tells you |
|---|---|---|
| One star | The cylinder | Has to be paired with a two-star handle or protective cover to make up the recognised three-star combination |
| Two stars | A security handle or protective cover | Shields the cylinder and can be paired with a one-star cylinder |
| Three stars | The cylinder | Reaches the three-star level by itself |
The stars «should» be accompanied by a «Kitemark», which shows that the product falls under the certification scheme. Before you rely on a claim, note the «Kitemark», the number of stars, the manufacturer and the product details. The Door and Hardware Federation’s guidance on «TS 007» sets out the two recognised routes to the three-star level.
Anti-Snap Is a Marketing Word, Not a Standard
A seller can attach "anti-snap" to any cylinder they like, because it is a description and not a certification. The claim worth trusting is a mark on the product, awarded by a certification body after testing; everything else is copy. The same discipline applies to tradespeople, and our guide to choosing a locksmith covers how to check what someone is actually claiming.
The Features Behind the Phrase
Anti-snap is normally shorthand for several separate features that get sold together under one label:
- Sacrificial section: engineered to break at a set point and leave the lock working.
- Anti-drill inserts: hardened parts that resist drilling.
- Anti-pick pins: pin designs that defend against picking.
- Anti-bump measures: a defence against a different approach again.
A cylinder with just one of these can be listed as anti-snap. So can a cylinder with all four and a certification behind them, and the two listings often read almost the same. The question to put to a seller or a locksmith is simple: which of these features does this cylinder have, and is it certified?
What a Listing Does and Does Not Prove
The rule is short: a product title is a claim, and a mark on the cylinder is evidence. When reading a listing:
- Look past the phrase. Find out whether a scheme and a rating are actually named.
- Check which part is rated. Is the rating for the cylinder, or for a handle sold alongside it?
- Look for the Kitemark. Is the marking described as Kitemarked?
One trap deserves naming. A two-star handle can be listed next to an uncertified cylinder, and the star rating in the headline then belongs to the handle rather than the cylinder. Ask for the certification mark that will be on the product in your hand, not the wording on the page. For what lock work tends to cost, see locksmith prices in Woking.
The marks themselves are distinct. «SS 312 Diamond» is a recognised security rating for door cylinders, awarded through «Sold Secure» once the exact cylinder model has passed the tests. Diamond is the top cylinder rating currently listed in the «Sold Secure» directory. «TS 007» uses stars. «SS 312 Diamond» and «TS 007» three-star are separate ratings, not two names for one thing.
Each rating covers only the exact product tested, and one does not prove the other, so never assume a three-star cylinder is Diamond rated or the reverse. Either is far better evidence than "anti-snap" alone. A claim needs checking for the particular model from the named manufacturer.
The Two Schemes That Do Mean Something
The two marks to recognise are «TS 007», which rates in stars, and «SS 312 Diamond», published by «Sold Secure». Both are recognised marks for cylinder security, they are run by different bodies, and any given cylinder may carry one, both or neither. For the wider picture of door lock standards, read what BS 3621, TS 007 and insurance approved really mean.
TS 007 and the Star Rating
«TS 007» is the cylinder and door hardware specification developed by Secured by Design with the Door and Hardware Federation and the Glass and Glazing Federation, and it rates products in stars. What changes a buying decision is that three stars can be reached two ways:
- Route one: a «TS 007» three-star cylinder on its own.
- Route two: a Kitemarked one-star cylinder combined with a «TS 007» two-star Kitemarked armoured handle or lock surround.
The scheme rates the assembled defence, because a cylinder can be reached through the handle and escutcheon as well as directly. For the combination to count, both parts have to be «TS 007» rated and Kitemarked. If you need new hardware supplied and fitted, either route can be specified.
When choosing, look for a recognised rating such as a «TS 007» three-star «Kitemark» or «SS 312 Diamond» certification. A verified «TS 007» three-star cylinder is tested to resist snapping and other recognised attack methods, and it «should» display the relevant «Kitemark» alongside its three stars. As separate systems with different test requirements, neither scheme can be called better from its name alone, and some products hold both.
SS 312 Diamond and Sold Secure
«SS 312 Diamond» is a cylinder security standard published by «Sold Secure», and it is the second mark a UK buyer is likely to come across. It is an independent scheme with its own testing, so a Diamond-marked cylinder has been assessed against that standard rather than against TS 007.
- Where to look: the cylinder face or body, the same place you would find a star rating.
- What to record: copy the marking in full. Use an official product record to confirm that it matches the specific model and manufacturer.
Remember that three stars without the relevant «Kitemark» are not enough to verify a «TS 007» three-star rating. Comparing the two schemes' test regimes in detail goes beyond what a householder needs: a mark from either is meaningful, and no mark is not. A rated cylinder is designed to resist attacks on the cylinder itself, but it cannot defend against every way into a property.
A rating is only part of the answer. A highly rated cylinder protects less well if it is the wrong length, sticks out more than it needs to (its projection), or sits in damaged hardware. It must suit the door's thickness, and because hardware varies, no single projection figure fits every door.
The Crime Prevention Website advises replacing an exposed cylinder with a BSI Kitemarked or SS 312 cylinder that resists bumping and snapping, together with the door handle or other protective hardware.
| TS 007 | SS 312 Diamond | |
|---|---|---|
| Rating style | Stars | Diamond |
| Run by | Scheme developed with the Door and Hardware Federation | Sold Secure |
| What it covers | Cylinders and protective hardware | Security cylinders |
| Where to look | Cylinder face or body, and on the handle | Cylinder face or body |
What Upgrading Actually Involves
On most uPVC and composite doors this is a cylinder swap, held by one screw and finished in a few minutes, not a new door or a new mechanism. A euro cylinder is normally a separate part, so it can usually be changed without touching the complete multipoint lock. "Anti-snap" refers to protection in or around the cylinder, not to the whole mechanism inside the door.
What changes
the old cylinder comes out and a rated one goes in, sized so it sits flush rather than proud.
What stays
the multipoint mechanism, the handle and the door itself, unless the handle is being upgraded at the same time.
What comes first
measurement. The replacement has to match the door's thickness and the existing geometry, so you measure before you buy. Our guide to how a replacement lock is measured and fitted walks through it.
A cylinder-only change may make sense when a key has been lost, stolen or possibly copied, or when the cylinder is worn or damaged. One honest limit: a rated cylinder in a door with a failing mechanism is still a door with a failing mechanism, and those are separate jobs.
What Else Is Worth Doing on the Same Door
The cylinder is one part of the door's defence, and the hardware around it does the rest. A good cylinder strengthens one weak spot, but a weakness in the handle, mechanism, hinges, frame or door reduces what it can do, so look at the door as a complete system.
The handle and escutcheon
a rated handle is one of the two routes to a three-star result, and it covers the cylinder.
The keep and alignment
a door that does not close properly is not protected by anything fitted to it.
The hinges
worth checking on an outward-opening door.
The glazing beside the door
a thumbturn within reach of a glass panel changes the picture.
Keep in mind that a «TS 007» or «SS 312» rating belongs to the product that was tested, not to the door as a whole. If only one thing gets done, do the cylinder first: it is usually the simplest change with the clearest effect.
Ask Us What Your Cylinder Is
Tell us what is on your door and we will read the markings with you, explain what the cylinder is, and give you a price for a change if you want one.
Have ready: the door material, a photograph of the cylinder face and body, and whether it sits flush or proud.
There is no call-out charge at any hour, emergency calls are answered 24 hours a day every day of the year, and every job is priced on the call from what you describe. [PROVIDER PACK: DBS check status of technicians] [PROVIDER PACK: public liability insurance details] [CLIENT TO CONFIRM: whether TS 007 or SS 312 rated cylinders are stocked and fitted as standard]
Ask What Cylinder You Have: 01483 377197
Arrange an inspection if you cannot verify the rating, the cylinder has no identifiable maker, it projects well past the handle, it moves in normal use, or the key sticks. An anti-snap cylinder is worth considering when it carries a verified «TS 007» or «SS 312» rating, fits the door properly and works with suitable protective hardware.
Anti-Snap Lock Questions
What does anti-snap actually mean?
An anti-snap cylinder aims to protect the lock when an attacker tries to break the section left exposed. The phrase names an intended feature but says nothing about how the product was tested.
Is anti-snap the same as high security?
Not necessarily. "Anti-snap", "snap-resistant" and "high-security" are product descriptions unless a recognised rating backs them up, and designs differ from one product to the next. A cylinder may include a section designed to break in a controlled position, along with other protective features.
Can I keep my existing handles?
If your handles are undamaged, secure and compatible with the replacement cylinder, you can usually keep them.
Which standard does my insurer mean?
Policies word this differently. Some ask for a lock that meets a particular «British Standard», others «may» refer to a multipoint locking system or to minimum security precautions. The relevant standards are «BS 3621» for certain key-operated locks, «TS 007» for replaceable cylinders and protective hardware, and «SS 312 Diamond» for security cylinders. «These standards apply» to different products and door arrangements, so read your policy wording and check with your insurer.
Does a rated cylinder make my door secure?
It strengthens one important part. The handle, mechanism, hinges and frame still matter. For lock work across Woking, see our.