An anti snap lock is a cylinder, or a cylinder and security fitting combined, built so that the core cannot be pulled or snapped out of the door with a screw and pulling tool; in Dutch this protection is called kerntrekbeveiliging.
Ask a burglar how they get through a Dutch front door and the answer is rarely picking the lock. It is core pulling: a screw into the cylinder, a sharp tug, and the front of the lock comes out. It takes seconds and makes little noise. An anti snap lock is designed to make that impossible. This blog explains the attack, the protection and how to see which one your Amsterdam door has.
How core pulling works
A standard euro cylinder is held in the door by one screw in the middle, and the thin section around that screw is the weak point. A burglar drives a hardened screw into the keyway, fixes a pulling tool to it and pulls. The front half breaks off or is drawn out whole, leaving the cam exposed. A screwdriver then turns the lock as if it were a key.
On older cylinders this works on the first try, which is why it is the most common attack on Dutch front doors.
What an anti snap lock does differently
- The cylinder has a sacrificial front section that breaks off in a controlled way, leaving the locking part inside the door and the cam out of reach.
- Hardened pins and plates inside the cylinder stop a screw from biting and a drill from getting through.
- A security fitting with a core pull protection plate covers the cylinder face, so there is nothing to grip or screw into. Only the keyway is exposed.
The fitting and the cylinder work together. A protected cylinder in a weak fitting can still be attacked through the fitting. A protection plate on an unprotected cylinder still leaves the core exposed through the keyway. In practice the upgrade is a set, and that set is what the lock security page describes.
How to check your own door
Stand outside. If the cylinder face is visible and sticks out beyond the handle plate, your door has no core pull protection. If the cylinder sits behind a solid plate with only the keyway showing, look for the SKG shield with stars on that plate. Two or three stars means tested protection. Older doors in Amsterdam almost always fall in the first group.
Which doors need it first
Every door that can be reached from the street or from a shared hallway: the front door, a basement door, a back door onto a courtyard and the shared entrance of a portiek. Inside doors do not need it. If you are replacing a cylinder anyway, this is the moment to add it.
What we do
Locksmith Amsterdam checks the cylinder and the fitting together, tells you whether one or both need replacing and fits an anti snap lock that matches your door thickness and your existing handles through our lock replacement service. Everything is done in one visit and you hear the price before we start. See our locksmith services for what else we can do at the same time.
Frequently asked questions
What is core pulling?
A burglary method where a screw is driven into the cylinder and the core is pulled out with a tool, after which the lock can be turned with a screwdriver.
What is kerntrekbeveiliging?
The Dutch term for core pull protection: a cylinder, a security plate or both, designed so the core cannot be pulled or snapped out of the door.
Is an anti snap lock the same as an SKG lock?
Not always. SKG stars show tested burglary resistance; core pull protection is one of the features tested. A two or three star cylinder with a matching plate has it.
Do I need to replace the whole lock for anti snap protection?
Usually only the cylinder and the outside fitting. The lock case in the door normally stays.
Does Locksmith Amsterdam fit anti snap locks?
Yes. Call +31 (0)20 210 1986, describe your door and we fit a matching cylinder and plate in one visit, with the price confirmed before we start.
Not sure whether your door can be snapped? Call Locksmith Amsterdam on +31 (0)20 210 1986. We check the cylinder and fitting on site and confirm the price before we start.
