What Is a Euro Cylinder Lock? A Complete Guide

What Is a Euro Cylinder Lock? A Complete Guide

Euro cylinder locks are among the most common locking mechanisms used in doors and some window systems across the UK. They are a modular, replaceable cylinder that operates the bolt within a lock case or multipoint mechanism when the key is turned. This post explains how euro cylinder locks work, the types you will encounter, how to measure and fit them, plus trade and DIY tips to ensure correct and secure installation.

How a euro cylinder lock works

A euro cylinder is a cylindrical barrel that sits through the door from one handle or escutcheon to the other. Turning the key rotates a central cam which operates the lock mechanism inside the door: retracting or extending deadbolts or engaging multipoint gearboxes. Because the cylinder is a discrete component, it can be replaced without changing the entire lock body; this makes maintenance, upgrades and rekeying straightforward for both homeowners and installers.

Common types of euro cylinder

• Single cylinder: keyed on one side only; usually used where access is only required from one side.
• Double cylinder: keyed on both sides; common on front and back doors where no thumbturn is needed.
• Thumbturn cylinder: keyed on the outside and has a thumbturn on the inside for easy egress.
• Half cylinder: one-sided cylinder for applications such as letterplates, some garage doors or certain window locks.
• Modular or adjustable cylinders: can be adjusted to suit a range of door thicknesses; useful for installers carrying stock.

Security features and standards

Not all euro cylinders offer the same level of protection. Key security features include anti-snap brass segments, anti-drill pins, mushroom pins to resist picking and anti-bump profiles. British insurance providers commonly require a TS007 three-star rated cylinder or equivalent; TS007 indicates resistance to common attack methods including snapping. Look for cylinders that meet BS EN 1303 for performance ratings and check for Sold Secure approval where enhanced burglary resistance is required.

Measuring a euro cylinder correctly

Accurate measurement is essential when ordering a replacement cylinder. Remove the fixing screw from the edge of the door, insert the key and turn slightly to allow the cylinder to slide out. Measure from the centre of the fixing screw hole to the outer face on each side. Record both measurements; cylinders are sold in paired lengths, for example 30/45 mm. If the cylinder protrudes too far beyond the face of the door it is more vulnerable to attack; choose a length that sits flush or close to flush with the external face.

Practical DIY replacement steps

• Tools needed: screwdriver, replacement cylinder, cloth, light penetrating oil if the fixing screw is stuck.
• Unlock the door and remove the centre fixing screw from the edge of the door.
• Insert the key, turn it slightly and gently pull the cylinder out; for stuck cylinders apply a small amount of oil and try again.
• Check the cam position on the new cylinder aligns with the gearbox; slight rotation may be required during insertion.
• Slide the new cylinder into place, replace the fixing screw and test operation with the door open: ensure the multipoint bolts operate and the key turns smoothly without binding.
• Fit escutcheons or handle trims and check clearance so the cylinder does not protrude excessively.

If the lock is part of a multipoint mechanism, operate the gearbox (thumbturn or key) while fitting to ensure the cam engages correctly; some multipoint locks require the door to be locked or unlocked before the cylinder will withdraw.

Trade tips for professionals

• Carry a range of cylinder lengths or use modular cylinders to avoid return visits; measure door thickness and the distance either side of the fixing screw before ordering where possible.
• For new builds or replacements specify TS007 three-star or Sold Secure cylinders on external doors to meet insurance expectations and to reduce callbacks.
• Check the product specification for cam types; some gearboxes require a particular cam profile or centring position. Matching the cam ensures smooth operation and prevents damage to the gearbox.
• Specify restricted key systems or master keying for communal and multiple occupancy sites to control key duplication and improve security management.
• For retrofit upgrades consider anti-snap cylinders specifically designed to protect against common snapping attacks; fitting an anti-snap cylinder and reinforced escutcheon will significantly raise security levels.

When to call a locksmith

Replacing a cylinder is straightforward for many doors, but call a professional if: the cylinder will not withdraw despite following procedures; the door is misaligned or binding; you suspect the multipoint gearbox is damaged; or the lock is part of an alarmed or special-purpose system. A locksmith can also advise on certified upgrade options to satisfy insurer requirements.

Compatibility with windows and different door types

Euro cylinders are widely used in uPVC, composite and aluminium doors, and in some aluminium or timber windows that use locking handles. Check the lock case or handle spindle alignment when fitting to windows; the cylinder cam must engage the internal locking mechanism. For patio doors the cylinder often operates a central multipoint gearbox; ensure any replacement is compatible with the multi-point mechanism and keeps the door secure.

Recommended Products

Based on this article, you may find these products helpful:

• TL Thumb Turn Euro Cylinder
• Ultion Plus TS007 3* Kitemarked Euro Key & Turn Cylinder
• ERAB Espagnolette Window Lock Universal Lock Replacement
• Multipoint Gearbox GU Old Style
• Patio Door Handle Set - 92PZ White

Conclusion and next steps

Euro cylinder locks are a versatile, replaceable component that supplyers and installers can use to tailor security to property needs. Choose a cylinder with the correct length, cam profile and security rating for the door type. For homeowners consider upgrading to an anti-snap, TS007 three-star cylinder where appropriate; for trade professionals carry modular options and confirm cam compatibility before fitting. For more detailed specifications, product recommendations and measuring guides visit our pillar page: /guides/euro-cylinders or contact our trade desk for assistance with orders and technical queries.