Anti-snap cylinders snap. That is the whole idea.

Lock snapping works because a euro cylinder is a long brass casting with a screw hole through the middle of it. Grip the part sticking out past the handle, lever it, and it breaks at the weakest section — which on a cheap cylinder is right at the cam, the piece that actually throws the bolt. Break it there and the cam falls out and the door opens.

What “anti-snap” does

It moves the break. A three-star cylinder has a sacrificial section cut into it outboard of the cam, so the casting fails there first. The attacker is left holding two inches of brass, the cam is still in the lock, and the lock still works. Some patterns add a hardened pin through the middle so the second half cannot be gripped either.

The mechanism is deliberately dumb, and that is why it is reliable. It is not a material that resists force; it is a shape that decides where force wins.

The two things that undo it

It sticks out. A cylinder should sit within about 3 mm of the handle plate. Every millimetre past that is a millimetre of leverage, and we have pulled cylinders standing 12 mm proud on doors whose owners had paid for three-star hardware. It is measured with a ruler and it takes fifteen seconds.

It is a one-star cylinder behind two-star furniture. TS 007 lets you reach three stars two ways: a three-star cylinder on its own, or a one-star cylinder behind a two-star handle. The second is legitimate and it is also fragile, because the handle is the part that gets changed by the next person who redecorates. We fit the first.

What we charge

£95 fitted, one cylinder, keyed to your existing key where the profile allows it, and keyed alike across every door on the same visit at no extra labour. If you have three doors and three keys, that last part is usually the real reason to do it.