How to Measure a Euro Cylinder

A euro cylinder is sold by its total length and by how that length is split across the two sides of the door. The standard way to express this is as two numbers — for example, 35/45 — where the first number is the measurement from the outside face of the door to the centre of the fixing screw, and the second is from that same screw to the inside face. The two numbers added together give you the total cylinder length. If you buy a cylinder that is even a few millimetres too long on the outside, the excess barrel protrudes beyond the door furniture, and that exposed section can be snapped off with a pair of grips in seconds. Cylinder snapping is one of the most common forced-entry methods used in the Midlands, and it works precisely because so many doors have an oversized cylinder fitted — often the original builder's choice rather than a security-conscious one.

Buying a cylinder that is too short creates a different problem: it may not engage the locking mechanism correctly, leaving the door insecure in a less obvious way. Getting the right size is therefore not just about the lock fitting neatly — it is about the door actually doing its job.

Open your door fully and look at the edge of the door — the narrow strip of wood, uPVC, or composite you see when the door is ajar. You will see the cylinder sitting inside the door, held in place by a single screw that runs through the door edge into the cylinder body. That screw is your reference point for everything that follows. First, measure from the outer face of the door (the side that faces the street) to the centre of that fixing screw. Write this number down — this is your external measurement. Next, measure from the centre of the same screw to the inner face of the door. This is your internal measurement. Add both together to get your total cylinder length. For a standard uPVC door you might find something like 35mm outside and 45mm inside, giving a total of 80mm — written as 35/45.

If your cylinder has a thumb-turn on the inside rather than a second keyhole, the measurement method is identical; the thumb-turn cylinder is simply a different style of the same format. Once you have your two numbers, check whether the external measurement is the same as, or less than, the internal one. If the outside number is significantly larger — particularly if the cylinder visibly protrudes past the door furniture when the door is closed — that is a red flag. A well-fitted anti-snap cylinder should sit flush with, or just slightly recessed into, the door furniture on the outside. If yours sticks out, it is worth speaking to a locksmith Kenilworth residents trust before the problem is exploited rather than after.

Cylinder snapping became widely reported across the UK about fifteen years ago and has remained a persistent method of entry in residential burglaries. The technique requires no specialist skill and takes only moments, which is why police forces and insurance companies across the country have encouraged homeowners to upgrade to TS007 3-star rated anti-snap cylinders. The TS007 3-star standard (which can be achieved by a 1-star cylinder combined with a 2-star door handle, or by a standalone 3-star cylinder) means the cylinder is designed to sacrifice a sacrificial section before the attack reaches the cam that operates the latch — buying time and defeating the method entirely.

Fitting the right size cylinder is the essential first step, because even a 3-star cylinder is vulnerable if it protrudes far enough to give an attacker something to grip. Many insurers, including those offering standard home contents policies in the CV8 postcode area, now specify TS007 3-star or equivalent protection as a condition of cover for uPVC and composite doors. If you are unsure whether your current cylinder meets that standard, calling a locksmith before your next renewal is a sensible move — not least because a lock change Kenilworth homes require is straightforward when planned, and far less stressful than dealing with a break-in. If you would like a quick assessment, call 01926 567506 and we will talk you through your options before anyone even sets off.

Once you have your measurement — say 40/45 — you can either source a replacement cylinder yourself or ask a locksmith to supply and fit one. If you are sourcing it yourself, look for a cylinder stamped or described as TS007 3-star, anti-snap, and anti-pick. Avoid cylinders with no visible security rating, as basic cylinders offer little more resistance than the original builder's fit. If you want a cylinder that also resists key-bumping and picking, look for one that also carries anti-bump and anti-drill ratings — these are increasingly standard on quality cylinders at no significant extra cost.

A professional door lock replacement Kenilworth service does more than simply unscrew the old cylinder and screw in the new one. A trained locksmith will check that the cam aligns correctly with the multipoint lock mechanism, test all locking points, check the door alignment and compression against the frame, and confirm the cylinder sits flush with the furniture. A poorly hung door — common in older uPVC frames that have dropped slightly over the years — can cause a correctly sized cylinder to feel stiff or fail to operate smoothly. That is worth diagnosing at the same time rather than discovering later. For uPVC door lock repair Kenilworth, the same visit often covers a full mechanism check, including the multipoint hooks, rollers, and locking points that run up and down the door edge.

If you are locked out rather than simply planning a cylinder upgrade, there are a few sensible checks worth making before anything else. Try all other external doors — back doors, French doors, any door you do not use as your main entrance. Check whether a trusted neighbour holds a spare key. If you live in a flat, speak to the building manager or letting agent, as a communal entrance lock may be their responsibility. If you are a tenant, your landlord or managing agent may hold a spare set. Only once these options are genuinely exhausted is it time to call for help.

When you do need a 24 hour locksmith Kenilworth, the process should be straightforward and transparent. Any reputable locksmith will confirm an exact price before starting work — the factors that shape that quote include the time of day (evenings, weekends, and bank holidays carry different rates), the type of lock and door, the parts required, and travel distance. You should never be surprised by the final amount. We will confirm the exact price on the phone before we set off, so you know exactly where you stand. We cover Kenilworth and the surrounding villages — including Leamington Spa, Warwick, Stoneleigh, and Burton Green — and as a 24 hour locksmith Kenilworth residents rely on, we send a locksmith straight away and are usually with you in about 30 minutes. For urgent help, call 01926 567506 at any time — day or night, including bank holidays.

Measuring and replacing a euro cylinder is the most common task we handle for uPVC and composite doors, but it is far from the only one. For properties with traditional timber front doors, the standard fit is a Yale-type nightlatch combined with a 5-lever mortice deadlock — the type insurers typically specify must meet BS3621 for home contents cover to remain valid. We carry out lock changes on both types, as well as emergency boarding when a door or window frame has been damaged during a break-in and needs to be secured before a joiner or glazier can be booked. Emergency boarding services are available around the clock for exactly these situations — a compromised door or window cannot wait until Monday morning.

For commercial properties in and around Kenilworth — offices, retail units, workshops — we also cover commercial lock changes, access point assessments, and emergency call-outs when a business cannot be secured at the end of the trading day. Whether it is a cylinder change on a residential flat in town or a full lock replacement on a workshop unit on the Kenilworth industrial estate, the approach is the same: measure correctly, fit the right grade of hardware, and leave the property properly secured. If you have been wondering how to change a lock or simply want a professional opinion on whether your current locks are up to scratch, we are available whenever you need us.

Kenilworth is a relatively compact town, but its housing stock is genuinely varied — Victorian and Edwardian terraces close to the Castle ruins, 1960s and 1970s estates further out, newer build developments on the edges of town, and a mix of flats, semis, and detached homes in between. Each type of property tends to have different door furniture, different lock grades, and sometimes quite different cylinder sizes, so local knowledge does matter when arriving with the right parts. We know the area well, and we keep a range of cylinder sizes and lock types in the van so that the most common replacements can be completed on a single visit without a return trip.

Our team covers Kenilworth and the surrounding villages and towns — including Balsall Common, Cheswick Green, Wroxall, and across into south Warwickshire — as a fully insured, mobile locksmith service operating every day of the year. There is no job too small and no hour too awkward. If you need a locksmith Kenilworth residents can call with confidence at 2am on a Sunday or at noon on a Tuesday, we are ready. Ring 01926 567506 and we will confirm your options and your price before anyone leaves.