Invisible Child Safety Locks for Cabinets: Fitting Magnetic Locks and Push-to-Open Latches

An invisible child safety lock consists of an internal magnetic lock that is unlocked from the outside using a magnetic key, ensuring cabinet fronts remain secure without visible catches.

When it comes to protecting cabinet contents from toddlers, external plastic latches often compromise the appearance of high-quality furniture. A technically clean and completely concealed solution is combining internal magnetic locks with a mechanical push-to-open system (touch latch). This method is suitable for almost all furniture units made of chipboard, MDF, or solid wood – from handleless fronts in living areas to sensitive storage spaces in humid rooms.

This guide is aimed at fitters and experienced DIY enthusiasts. It explains the exact positioning, installation, and fine adjustment of the fittings. The installation requires precise work to the millimetre, but with proper preparation takes only about 15 to 20 minutes per door.

The Technology Behind the System

A magnetic locking system acts like an invisible switch inside the cabinet carcass. The lock consists of a spring-loaded locking bolt that engages with a striker plate (the latch catch) mounted on the carcass. When the magnetic key is brought close to the front from the outside, the magnetic pull draws the bolt back against the spring pressure – unlocking the door.

For handleless doors, this system must strictly be combined with a push-to-open latch. Essential for technical understanding: push-to-open and soft-close (damping) are opposing mechanisms. A push-to-open latch requires the momentum of the spring to push the door open. Damped hinges would block this movement. Therefore, handleless fronts with a magnetic lock require unsprung hinges or specialised hinges with an opening spring.

Required Tools and Materials

The following tools and hardware components are required for professional installation:

• Cordless drill with torque control
• Wood drill bits (Ø 2 mm for pilot holes, Ø 5 mm for System 32 with push-to-open latches)
• Depth stop for the drill bit (prevents drilling through the front)
• Pozi screwdriver (PZ size 2)
• Joiner's square, tape measure, and pencil
• Magnetic lock system (comprising lock body, striker plate, and magnetic key)
• Push-to-open latch (spring plunger with adapter plate)
• Chipboard screws (countersunk, typically 3.5 x 16 mm)

Step-by-Step Guide: Fitting the Magnetic Lock

The greatest challenge during installation is the exact alignment between the striker plate (on the carcass) and the lock body (on the door). A deviation of more than 1.5 mm often causes the bolt to jam.

1. Determine the Position

Choose a position out of reach of children, for example in the top third of the door. The lock should be mounted on the side opposite the concealed hinge (the closing edge). When working on units such as bathroom cabinets, ensure that the lock does not collide with internal shelves or shelf supports. Measure at least 50 mm down from the top edge of the door.

2. Mount the Striker Plate on the Carcass

The striker plate is fixed to the inside of the carcass.

1. Measure the thickness of the door front (e.g. 19 mm).
2. Add the required gap dimension (strictly 2 mm to 3 mm for push-to-open systems).
3. Position the striker plate at this total distance (e.g. 21 mm) from the front edge of the carcass.
4. Mark the drilling holes and pre-drill with the 2 mm bit to a maximum depth of 10 mm.
5. Secure the striker plate using the supplied chipboard screws.

3. Transfer the Position to the Door

Many manufacturers supply an installation template. If this is not provided, use a simple trick: apply a piece of double-sided tape to the back of the lock body, click it into the mounted striker plate, and close the door firmly. The lock body will now adhere to the exact position on the inside of the door.

4. Secure the Lock Body to the Front

1. Carefully open the door. The lock body will remain stuck to the front.
2. Mark the fixing holes with a pencil.
3. Remove the lock and pre-drill the holes with the 2 mm drill bit. Caution: Always use a depth stop to avoid drilling right through the front.
4. Screw the lock body into place. Take care not to strip the PZ drive on the screws.

5. Functional Test and Deactivation

Test the mechanism with the door open by holding the magnetic key against the corresponding spot on the outside. The bolt should retract audibly. Most high-quality magnetic locks have a small switch on the housing. This allows the locking bolt to be permanently retracted – useful once children are older and the safety lock is temporarily unneeded.

Step-by-Step Guide: Fitting the Push-to-Open Latch

To ensure the door pops open after being unlocked by the magnet, install the push-to-open latch.

1. Choose the Mounting Method

Push-to-open latches can either be inserted directly into a 5 mm hole in the carcass side panel (where a System 32 hole pattern exists) or screwed on using a linear or cruciform adapter plate. Position it close to the magnetic lock for optimal force transmission.

2. Screw on the Adapter Plate

Align the adapter plate flush with the front edge on the inside of the carcass. Pre-drill the holes and secure the plate with chipboard screws (3.5 x 16 mm). For tall wardrobes, mounting at standard handle height (even if no handle is fitted) provides the optimum leverage point.

3. Clip in the Plunger and Adjust the Gap

Clip the push-to-open cylinder into the adapter plate. The plunger tip can be adjusted in length by rotating it. Adjust the plunger so that a gap of exactly 2 mm to 3 mm remains between the carcass and the closed front. This travel is essential to allow the door to be pressed inward slightly to activate the latch release.

Common Faults and Expert Advice

Even with careful installation, operational issues can occur. Here are the technical causes and remedies:

• The door cannot be pushed inward: The gap is too narrow. If the door sits tightly against the carcass, the push-to-open mechanism lacks the travel needed to trigger. Rotate the plunger inward slightly to widen the gap to 2.5 mm.
• The magnetic lock does not open reliably: This is usually caused by an excessively thick door front. Standard magnetic locks operate through material thicknesses up to 25 mm to 30 mm maximum. On thicker solid wood doors, the magnetic pull is insufficient to overcome the bolt spring.
• Incorrect hinge selection: As mentioned, a concealed hinge with an integrated soft-close damper blocks the push-to-open action. The plunger presses against the damper, leaving the door slightly ajar without swinging open. Replace the hinges with unsprung or standard mechanical models.
• Collisions with runners: When installing magnetic locks on drawers, pay attention to the slide mechanisms. With a full extension slide or single extension runner, the lock must be mounted high enough on the drawer side so it does not strike the roller or ball bearing track when closing.

Alternatives for Specific Furniture Types

An invisible magnetic lock is not the best choice for every unit. When the primary requirement is securing valuables or documents rather than childproofing, traditional mechanical systems are preferable.

For cupboard doors in offices or media units, key-operated furniture locks are standard. If a tall cabinet such as a filing cupboard needs securing along its entire height, an espagnolette lock is ideal. For single drawers or small compartments, a compact cylinder cam lock is often sufficient. In hallway furniture such as shoe cabinets and drop-front shoe tippers with flap mechanisms, fitting magnetic locks is tricky due to the opening angle; side-mounted push-button cylinder locks provide a more technically reliable option.

FAQ – Frequently Asked Questions About Installation

Can I use magnetic locks on full overlay and inset doors? Yes, the system functions regardless of hinge crank. For inset doors (where the front sits flush inside the carcass frame), the striker plate simply needs to be set further back into the carcass by the exact thickness of the front plus a 2 mm gap.

What happens if the magnetic key is lost? The lock stays locked. However, any standard strong neodymium magnet can be used from the outside to retract the bolt. Replacement magnetic keys can also be sourced easily from hardware specialists.

What torque setting should be used when driving screws? Set the cordless drill to a very low torque level (setting 2 or 3). Because the screws are typically only 16 mm long and fix into soft chipboard, they strip easily. A stripped thread provides no purchase, causing the lock to tear out under load.

How can I pinpoint the lock position from the outside? After installation, place a small, discreet sticker on the outside of the door precisely where the internal lock body is situated. This ensures authorised users always know where to place the magnetic key.