Phase 1: Removing the Old Euro Cylinder Lock
Step 1: Release the Cylinder Open your door and look at the face edge (the metal strip where the door latches into the frame). You will see a central retaining screw located roughly in line with the bottom of the cylinder lock. Use a Phillips head screwdriver to unscrew and remove this central screw.
🖼️ [Image: Close-up of a screwdriver unscrewing the central retaining screw located on the thin edge of an open uPVC/composite door.]
Step 2: Align the Cam and Remove the Cylinder The lock is held inside the door by a central rotating mechanism called a "cam." You need to align this cam flush with the lock body to slide it out.
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If you have a keyed lock: Insert your key into the lock. Turn the key slightly—approximately 45 degrees to the left or right. Apply gentle pulling pressure as you turn until you feel the lock slide free, then pull the cylinder entirely out of the door.
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If you have a thumb-turn lock: Turn the thumb-turn slightly to align the cam and gently pull the cylinder out.
🖼️ [Image: A hand turning the key in the cylinder at a 45-degree angle while simultaneously pulling the lock cylinder horizontally out of the door handle socket.]
Phase 2: Measuring for the Replacement Lock
Crucial Tip: If a cylinder protrudes too much from the handle, it becomes a major security risk (vulnerable to "lock snapping"). Ensure your measurements are exact.
Step 3: Measure the Cylinder Place your removed cylinder flat on a table. You need to take two measurements starting from the central screw hole (the threaded hole in the middle where the retaining screw went in):
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Measurement A (External size to centre): Measure from the outside-facing end of the cylinder to the dead-centre of the screw hole.
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Measurement B (Internal size to centre): Measure from the inside-facing end of the cylinder to the dead-centre of the screw hole.
🖼️ [Image: A euro cylinder lying flat against a ruler. Arrows labelled 'A' and 'B' indicate the distance from each end of the barrel to the centre of the middle screw hole.]
Step 4: Double Check Your Measurements Measure the overall length of the cylinder from end to end. This total length should exactly equal the sum of Measurement A and Measurement B. (For example: If A is 40mm and B is 50mm, the total length must be 90mm, and you will need to purchase a 40/50 offset cylinder).
🖼️ [Image: A ruler measuring the full length of the cylinder from the absolute left edge to the absolute right edge, confirming the total length.]
Phase 3: Choosing and Installing the New Lock
Step 5: Insert the New Cylinder Take your new euro cylinder and insert the key (or grip the thumb-turn). Turn it slightly to about 45 degrees so that the central black cam sits flush and hidden inside the cylinder body.
🖼️ [Image: The new shiny euro cylinder held in hand. The key is turned so the black cam in the middle is perfectly aligned with the rest of the lock body.]
Step 6: Slide into the Door Slide the new cylinder into the hole in the door handle. Ensure that the correct side is facing outwards (if you bought an offset cylinder, make sure the specific external dimension faces the outside of the door to sit flush with the handle).
🖼️ [Image: The new lock being slid back into the empty keyhole of the door handle. The lock is shown sitting flush against the handle plate, not sticking out.]
Step 7: Secure the Lock Once the cylinder is in place, test the locking mechanism with the key to ensure the cam engages with the door's internal locking points correctly. Finally, reinsert the central retaining screw into the face edge of the door and tighten it securely.
🖼️ [Image: A screwdriver tightening the central retaining screw back into the side edge of the door to secure the new lock in place.]
Test the lock a few times while the door is open to ensure smooth operation before closing the door.