Replacing a cylinder lock: DIY or call a locksmith?
A euro-profile cylinder is simpler to replace than most people think — but there are two pitfalls that can make the difference between a secure door and a security risk.
How a cylinder lock works
Almost every Dutch front door has a euro-profile cylinder: an oval cylinder held in place by a single set screw on the edge of the door. You can remove it with a screwdriver and a key — no special tools required.
When replacing a cylinder there are two things that matter above all else: the correct size and a certified (SKG) cylinder.
DIY: when it's fine to do it yourself
- You know the exact size of the current cylinder (inside and outside measurement).
- You are replacing like-for-like with an equivalent or higher SKG rating.
- The door frame and lock housing are undamaged.
- You want to use keyed-alike cylinders (multiple doors, one key) — that requires careful advance planning.
Better to call a professional when
- You are unsure of the size and do not want to risk buying the wrong one.
- The old cylinder was drilled out or shows damage from a break-in attempt.
- You want to upgrade your security class (e.g. from SKG★★ to SKG★★★).
- Multiple doors need to be keyed alike — a locksmith orders matching cylinders from the same series.
- You want certainty that old keys no longer work and the new cylinder is correctly fitted.
Pay attention to the size
A cylinder that is too long sticks out beyond the door fitting. That creates a core-pull risk: a burglar can snap off the protruding part with a pair of pliers and turn the lock open. A cylinder that is too short prevents the door from closing properly.
Common sizes are 30/30, 30/35 and 35/40 mm — but many other sizes exist. Measure from the centre of the set screw to each end of the cylinder. Note both figures.
Do you want keyed alike cylinders — one key for the front door, back door and shed? Then order all cylinders from the same series in advance. A locksmith can handle this for you.
Frequently asked questions — cylinder replacement
Can I replace a cylinder lock myself?
Technically yes — replacing a euro-profile cylinder involves removing one set screw and sliding out the old cylinder. The main pitfall is choosing the correct size. Too long a cylinder creates a core-pull risk; too short and the door will not close properly. Also make sure you choose an SKG-certified cylinder for your security class.
How do I know what size cylinder I need?
Measure from the centre of the set screw to both ends of the cylinder. Note both measurements: for example 30/35 mm means 30 mm on the outside and 35 mm on the inside. If in doubt, send a photo via WhatsApp — I can often tell the size at a glance.
When is cylinder replacement advisable?
Replace your cylinder when: you have lost a key and cannot rule out that it has fallen into the wrong hands; you have moved into a new home and do not know how many keys are in circulation; the lock is stiff or difficult to operate; or there has been a break-in attempt and the cylinder shows signs of damage.
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