Dismantling a Cam Lock: Removing the Lock Cylinder and Retaining Nuts Without Scratching Veneer

May 2, 2026

A cam lock in furniture is usually secured by a rear retaining nut on an M19 or M22 thread and can be removed without damage by counter-holding and precisely loosening this nut.

Replacing or dismantling a furniture lock requires precision. Whether dealing with a classic office cabinet, a metal locker, or lockable base cabinets for a kitchen run without appliances: the mechanics are often identical, yet the surfaces leave no room for error. High-quality veneer such as oak, beech, or wenge splinters quickly if tools slip or if the lock cylinder rotates uncontrolled during removal.

This guide is aimed at fitters and experienced tradespeople. It explains the professional dismantling of a cam lock, the differences between timber and sheet steel fronts, and how to protect sensitive surfaces.

Preparation: Difficulty Level and Time Required

Time required: approx. 10 to 15 minutes per lock.
Difficulty level: Medium. The mechanical solution is simple; the challenge lies in protecting the surface.
Area of application: Cabinets, chests of drawers, desks, and steel cupboards.

Required Tools and Materials

For professional dismantling without damaging the front or the cylinder housing, you will need the following tools:

Open-ended spanner or socket spanner: Sized to fit the rear retaining nut (commonly spanner size 22 mm, 24 mm, or 27 mm).
Cross-head screwdriver: Size PH2 or PZ2 (for the cam retaining screw).
Slotted screwdriver: Narrow blade (approx. 3 mm) for releasing any retaining clips (horseshoe clips).
Masking tape: Residue-free painters tape to mask the front surface.
Penetrating oil: Only for heavily corroded threads (e.g. on old steel lockers).

Never use water pump pliers or combination pliers to loosen the large lock nut. The teeth of the pliers will inevitably damage the soft brass or zinc die-cast thread of the cylinder.

Step-by-Step Guide: Dismantling a Cam Lock

The following guide walks you through the standard process for a cam lock or furniture lock secured with a nut.

Step 1: Secure and Mask the Surface

Before applying any tools, the surrounding veneer must be protected. Much like a scalpel in surgery, the open-ended spanner must be applied accurately to avoid damaging the delicate wood veneer. Generously mask the timber or decorative front around the cylinder head with masking tape. On a steel cupboard, the tape protects the powder coating from scratches. Also mask the inside of the door around the lock, as the spanner can easily slip when loosening the nut.

Step 2: Remove the Cam (Latching Arm)

On the back of the lock (inside the cabinet) sits the cam. This is usually fastened to the cylinder core with a small screw.

Insert the key into the lock to keep the cylinder steady.
Loosen the cam screw using the appropriate screwdriver.
Remove the screw, any spring washer (flat washer) present, and the cam, then set them aside.

Step 3: Loosen the Retaining Nut or Retaining Clip

The main fixing mechanism is now exposed. There are two common systems:

Variant A: The Retaining Nut (Standard) The lock housing features an external thread holding a flat hexagonal nut. Place the open-ended spanner flat and flush against the nut. With your other hand, hold the cylinder head firmly on the front of the door (or leave the key inserted and hold it). This is crucial: if you turn the nut and the entire cylinder rotates with it, the anti-twist lug (a small metal pin or tooth on the cylinder head) will gouge into the veneer, leaving deep, irreparable grooves. Turn the nut anticlockwise to unscrew it.

Variant B: The Retaining Clip (Common on Sheet Metal Lockers) On some models, particularly in a steel cupboard, the lock is not threaded but held under tension by a U-shaped retaining clip (fork spring). Place the narrow slotted screwdriver into the eyelet or bend of the clip and carefully lever it sideways off the cylinder housing. Ensure the spring steel clip does not spring away uncontrollably.

Step 4: Pull Out the Lock Cylinder

Once the nut or clip is removed, you can pull the lock cylinder forwards out of the hole. If the cylinder is tight in the wood, apply gentle pressure from behind. Do not strike the thread with a hammer, as this will deform it. Pull the cylinder straight out so that the edges of the hole in the veneer do not fray.

Step 5: Clean the Hole and Remove the Tape

Peel the masking tape off carefully at a flat angle to prevent wood fibres from lifting on older oak or beech veneer. Clean dust and residue from the edges of the hole (usually 19 mm or 22 mm in diameter).

Specific Considerations for Different Materials

The dismantling process differs in detail depending on the base material of the furniture front.

Real Wood Veneer (Oak, Beech, Wenge)

Real wood veneers are often only 0.6 mm to 1.5 mm thick. They are extremely sensitive to torsional forces. If the lock's anti-twist lug was pressed too deeply into the wood during installation, a piece of veneer may chip off when pulling out the cylinder. Work with utmost care and press lightly on the surrounding veneer with your thumb while removing the lock to stabilise it.

Steel Cupboards and Lockers

A cam lock for a steel cupboard often features flattened sides on the thread (double D-profile) that fit into a punched, non-round opening in the sheet metal. This acts as an integrated anti-twist protection. Here, the cylinder cannot rotate when loosening the nut. However, nuts on metal-to-metal connections tend to seize. A drop of penetrating oil left to work for 10 minutes makes removal considerably easier.

Retro-Fitted Furniture in Functional Spaces

When adapting units for commercial use or integrating a lock into a kitchen run without appliances, you will often encounter melamine-faced chipboard. These coatings are harder than natural wood veneer, but they chip with sharp edges under point loads (e.g. from slipping tools). Comprehensive masking is essential here as well.

Common Mistakes During Dismantling

Using Pliers: As mentioned, pliers ruin the fine thread. The lock cannot be reinstalled afterwards, and a new nut cannot be threaded on.
Forgetting the Cam: Forcing the lock through the hole with the cam still attached will cause severe damage to the inside of the door.
Failing to Counter-Hold: If the cylinder is not held firmly on the front side, it will turn along with the tool. The sharp edges of the cylinder collar will scratch the lacquer or veneer in a circle.

FAQ: Frequently Asked Questions

How do I dismantle the cam lock if the key is missing? If the cabinet is open, you can remove the lock as described above. If the cabinet is locked, the cylinder core must be drilled out. To do this, position an HSS drill bit (Ø 5 mm or 6 mm) centrally below the keyway and drill through the pin tumblers. The core can then be turned with a screwdriver to open the cupboard.

What is the standard hole diameter for a furniture lock? Industry standards for furniture locks are generally a mounting diameter of 19 mm (for thin materials and sheet metal) or 22 mm (for timber doors from 16 mm thickness). Measure the thread diameter of the old lock accurately with a vernier caliper before ordering a replacement.

What should I do if the veneer tears slightly during removal? Small cracks in wood veneer can be filled with matching hard wax (furniture wax). For dark woods such as wenge, a touch-up pen is often sufficient to darken the pale substrate (chipboard or MDF) exposed under the scratch. For larger damage, covering the entire front with self-adhesive veneer can be a solution, though it requires experience in surface bonding.

Can I replace a clip-fixed lock with a nut-fixed lock? Yes, provided the hole diameter (e.g. 19 mm) and the anti-twist shape (the flat section in the hole) match. A retaining nut often provides a firmer and more uniform hold on timber materials than a clip, which can press into soft wood.