Blanking Plugs & Cover Caps: Self-Adhesive vs Push-Fit (Dimensions & Types)

January 28, 2026

Blanking plugs and cover caps are functional hardware fittings that visually conceal open drill holes, screw heads, or cam connectors while protecting them from dust and moisture. Whilst push-fit caps grip mechanically inside the hole or screw drive via a pin, self-adhesive caps adhere flat to the surrounding substrate.

What exactly are blanking plugs and cover caps?

After assembling carcases using wood screws and furniture screws or fitting furniture connector systems, recesses inevitably remain on the panel surface. Cover caps serve to conceal these technically necessary openings. They act like a visual dressing over the structural marks of furniture assembly, restoring a seamless surface. At the same time, they prevent dirt from accumulating in holes, such as unused hole lines, and stop moisture from penetrating the unprotected core of a chipboard.

Types and variants: Self-adhesive vs push-fit

Depending on the type of fixing and the underlying hardware fitting, fitters distinguish between two fundamental systems:

Push-fit cover caps (Blanking plugs)

These caps are generally manufactured from injection-moulded plastic. They feature a pin or ring on the underside that is pressed precisely into the matching component.

Screw caps: The pin is shaped to engage directly with the screw drive (e.g. PZ or TX). This requires an exact match with the screw head, for instance with wood screws PZ1.
Hole plugs: These are pressed directly into unused drill holes, such as in a System 32 grid for shelf supports.
Cam caps: These clip over the outer edge of the round cam lock housing.

Self-adhesive cover caps

These flat discs are made of melamine resin or thin PVC and are coated on the reverse with a strong acrylic adhesive. Rather than being pushed into the opening, they are stuck flat over the drill hole onto the decorative surface. They are exceptionally discreet and available in countless finishes, from self-adhesive cover caps wood to solid colours such as self-adhesive cover caps white or self-adhesive cover caps black.

Dimensions, standards, and typical values

When selecting caps, exact millimetre measurements are crucial for a precise fit and a flush finish:

Diameter (self-adhesive): The standard is 14 mm for conventional screw heads and 20 mm for larger drill holes or cam connectors.
Material thickness (self-adhesive): Typically 0.3 mm to 0.5 mm to ensure an almost imperceptible profile.
Drill hole diameter (push-fit plugs): Common dimensions for blanking plugs in carcase construction are 3 mm, 5 mm, 8 mm, and 10 mm.
Cam diameter: Caps for standard Minifix connectors usually have an internal diameter of 15 mm.

Usage and selection during installation

The choice between push-fit and adhesive caps depends on the installation scenario. If a countersunk screw is driven completely flush or slightly recessed into the wood, a self-adhesive cap is the flattest solution. In this case, the surface must be entirely free of dust and grease so that the adhesive achieves its full bonding strength. With a broad selection of decors, such as self-adhesive cover caps oak or self-adhesive cover caps grey, screws on melamine panels can be rendered practically invisible.

Push-fit caps are used when deeper cavities need closing or when round-headed screws are fitted, over which a flat adhesive pad cannot be applied smoothly.

Related terms

Cam connector: A two-piece carcase fitting whose round housing is often concealed with a 15 mm cap.
System 32: Standardised line drilling pattern (usually 5 mm diameter spaced at 32 mm intervals) whose unused holes can be sealed with blanking plugs.
Countersunk head: A screw head shape that sits flush within the material, making it ideal for self-adhesive caps.