Cam Lock vs Biscuit Joint vs Wooden Dowel: Furniture Connectors Compared

November 16, 2025

Cam lock fittings provide a detachable clamping force between panels, whereas biscuit joints and traditional wooden dowels are designed for permanently glued constructions.

Which Furniture Connector for Which Project?

When building a cabinet carcass, joiners and fitters must decide how individual board materials will be joined. Selecting the correct system affects not only the stability and shear strength of the structure, but also whether the furniture can be disassembled at a later stage. A cam lock fitting acts like a mechanical lock that can be opened again at any time, whereas glued dowels join wood permanently and inseparable.

Each system requires specific tools, different machining tolerances, and offers its own mechanical advantages. This technical comparison examines the properties of the three most common furniture connectors to help you make the best choice for your specific construction scenario.

What Is a Cam Lock Fitting?

A cam lock fitting (eccentric connector) is a two-part fitting primarily used in industrial furniture manufacturing and flat-pack carcasses. It consists of a round cam casing (usually made of die-cast zinc) and a connecting bolt/pin (made of steel, often with a thread for wood or for an insert socket).

The mechanism relies on tensile force. The casing is inserted into a blind hole drilled into the face of one panel. The connecting bolt sits in the edge or face of the opposing panel. When turning the cam using a cross-head or Torx screwdriver, the head of the bolt is pulled in. This clamps the two components firmly together.

Typical dimensions for machining:

Hole for the cam casing: usually 15 mm diameter (drilled with a Forstner bit).
Drilling depth: dependent on panel thickness, typically 12 mm for a 16 mm thick panel or 14 mm for a 19 mm thick panel.
Hole for the bolt: 5 mm diameter.
Drilling distance (distance from edge to the centre of the cam): frequently 24 mm or 34 mm.

To increase stability against lateral shear forces, cam lock fittings are in practice almost always combined with traditional wooden dowels.

What Is a Biscuit Joint?

A biscuit joint, often referred to by trade professionals as a Lamello after the original inventor, is an oval jointing wafer. It is manufactured from compressed beech wood, or less commonly from plastic. The wafers feature a diagonal wood grain pattern to ensure high break resistance.

Biscuits are inserted into routed slots and glued. Water-based wood glue (PVAc adhesive) causes the compressed beech wood to swell inside the slot. This creates an extremely strong, form-fitting, and permanent joint. The greatest technical advantage of this carcass connector type is its lateral tolerance. Because the routed groove is slightly longer than the biscuit itself, panels can still be adjusted sideways by a few millimetres during glue-up to align them perfectly flush.

Machining strictly requires a biscuit jointer. The standard cutter blade thickness is 4 mm.

What Is a Wooden Dowel?

The classic wooden dowel (fluted dowel pin) is the oldest and most widely used connector in furniture making. It is mostly made of beech wood and features longitudinal fluting. This fluting is technically essential: it allows excess glue to escape from the drill hole when driving the dowel in. Without these channels, the glue would become compressed, which in the worst-case scenario leads to hydraulic splitting of the chipboard or solid wood.

Standard diameters in cabinet making are 6 mm, 8 mm, and 10 mm, with lengths between 30 mm - 40 mm. Drill holes must be positioned with absolute precision and squareness. Even an offset of 0.5 mm prevents panels from sitting flush or stops the dowel from inserting cleanly.

Direct Comparison of the Differences

To evaluate these systems for a specific application, several mechanical and processing parameters must be compared:

Demountability of the joint:
Cam lock fitting: Completely and repeatedly demountable without damage.
Biscuit joint: Permanently glued, non-demountable.
Wooden dowel: Permanently glued, non-demountable (unless used dry merely as an alignment pin).
Machining tolerance:
Cam lock fitting: Low. Holes must sit precisely to the millimetre, otherwise the bolt will not engage with the casing.
Biscuit joint: High along the length of the slot. Panels can be adjusted perfectly flush during glue-up. However, height tolerance (panel thickness) is zero.
Wooden dowel: Zero tolerance in all directions. Requires exact marking out or the use of drilling jigs.
Required tools:
Cam lock fitting: Drill, wood drill bit (5 mm), Forstner bit (15 mm).
Biscuit joint: Dedicated biscuit jointer machine strictly required.
Wooden dowel: Drill, brad-point wood drill bit, depth stop, dowel centres/jig.
Load bearing:
Cam lock fitting: Absorbs high tensile forces (holds panels together), but only limited shear forces.
Biscuit joint: Absorbs very high shear forces, aligns panels. Tensile force is provided by the glue.
Wooden dowel: Absorbs shear forces in all directions exceptionally well.

Which Joint Suits Which Scenario?

The decision is typically made based on requirements for transport, assembly location, and available workshop machinery.

When should you choose a cam lock fitting? This fitting is the primary choice for large wardrobes that must be assembled flat on the floor and then stood upright, or for furniture that will be dismantled during a house move. It is the standard for flat-pack furniture. For panel alignment and taking up lateral forces, it should always be paired with wooden dowels.

When should you choose a biscuit joint? Biscuit joints excel along long carcass edges, mitred joints (e.g. panels cut at 45°), and when building bookcases that are permanently glued. The ability to shift and align panels slightly whilst clamping makes them indispensable for joiners.

When should you choose a wooden dowel? Round dowels are ideal for smaller cabinets, drawer boxes, chairs, and tables. They are cost-effective and do not require expensive specialist machinery. In combination with modern connectors and brackets, they frequently serve purely for alignment. For special tasks, such as joining thick kitchen worktops, neither dowels nor biscuits are used, but rather dedicated worktop connectors that generate immense clamping forces via threaded bolts.

Frequently Asked Questions (FAQ)

What are the dimensions of biscuit joints and when do I use each size?

The wafers are standardised and primarily used in three standard sizes, which depend on the board thickness:

Size 0 (47 x 15 x 4 mm): For narrow components and panel thicknesses of 10 mm - 12 mm.
Size 10 (53 x 19 x 4 mm): For panel thicknesses of 13 mm - 15 mm.
Size 20 (56 x 23 x 4 mm): The most common size for standard furniture construction from a panel thickness of 16 mm upwards (e.g. 19 mm MFC).

Are plastic carcass connectors just as strong as metal versions?

For load-bearing joints in large wardrobes, die-cast zinc cam casings and steel bolts are the technical standard. Plastic connectors are mainly used in lightweight constructions, as back panel fittings, or in innovative clip-on systems that assemble without tools. When handling high tensile forces, metal provides significantly higher pull-out resistance.

Can cam lock fittings and biscuit joints be combined?

Yes, this combination is frequently used in professional cabinet making when a carcass needs to remain demountable whilst requiring high precision during alignment. The cam lock provides the clamping force (replacing sash clamps during assembly), while the biscuit (used dry without glue in this case) keeps panels perfectly flush on one plane and prevents twisting.